AU691938B2

AU691938B2 - Process of and apparatus for providing at least a partial barrier to moisture vapour transfer through the surface of a material and/or for removing moisture from a material

Info

Publication number: AU691938B2
Application number: AU29170/95A
Authority: AU
Inventors: Howard Bracken; Donald Sanderson Thomas
Original assignee: Microwave Processing Technologies Pty Ltd
Current assignee: SUSTAINABLE WORLD TECHNOLOGIES Pty Ltd
Priority date: 1994-07-11
Filing date: 1995-07-11
Publication date: 1998-05-28
Anticipated expiration: 2015-07-11
Also published as: AU2917095A

Description

WO 96/02153 PCT/AU95/00418 1 PROCESS OF AND APPARATUS FOR PROVIDING AT LEAST A PARTIAL BARRIER TO MOISTURE VAPOUR TRANSFER THROUGH THE SURFACE OF A MATERIAL AND/OR FOR REMOVING MOISTURE FROM A MATERIAL Technical Field This invention relates to a process of and apparatus for providing at least a partial barrier to moisture vapour transfer through the surface of a material without substantially spoiling the material, a process of and apparatus for removing moisture from a material without substantially spoiling the material, and a process of and apparatus for providing at least a partial barrier to moisture vapour transfer through the surface of a material and for removing moisture from the material without substantially spoiling the material.

Background of the Present Invention In the snack food and home microwaveable prepared food sectors of the food processing industry are of major world wide economic importance and are rapidly expanding in response to the demand of community changing lifestyles. However, the nutritional and diet value of many of such products and in particular snack foods is widely criticised and is the subject of increasing public concern and market awareness.

A major reason for the low nutritional quality of many of the products in the snack food sector is due to the production difficulties which are experienced in the processing of many of the wholesome, basic food products, such as for example, cheeses, meats, fruits, vegetables and berries, into high quality, long shelf life, nutritious, non-chewy, flavoursome products having consumer appeal. Of the many basic food products affected in this manner, cheese is one of the most important due to its availability for processing on a year round basis and because of its high nutritional and energy properties and important contribution to balanced food diets. As a consequence of these processing difficulties, many of the cheese snack products in the market are bland and of poor nutritional value and lack customer appeal. These products often consist of a cereal or similar core material finished in a cheese flavouring or cheese coating. The processed quality of other dried snack food products, such as for example, meats, fruits, vegetables and berries which could be considered as nutritious additives to cheese based snack food products are themselves typically characterised after processing as having tough skins, chewy texture and bland taste devoid of any WO 96/02153 PCT/AU95/00418 2 significant distinguishing flavour or taste. Some processes used in the cooking of foods, and particularly for example that relating to boiling, stewing, baking, leavening, frying, grilling and toasting have been observed and practised for centuries.

Notwithstanding the development of the industrial food processing industry and the introduction of more sophisticated cooking and drying methods and the advent of microwave heating, the food cooking and food processing methods and technologies and operating techniques in use today still remain more of an art than an inventive science. It is known that the processing of cheeses, fruits, meats, vegetables, spices and other agricultural produce having a distinctive taste, texture and aroma, by the use of conventional heating, cooking and drying technologies and methods and processes such as convection ovens, hot air cooking and drying systems, radiant heating and conductance heating systems, all cause changes to the surface properties of the product and volatilise to a greater or lesser degree the low molecular weight compounds which give rise to much of the distinctive properties of the fresh product. It is apparent that there is a need for a processes for of removing moisture from a material without substantially spoiling the material.

Object of Invention Objects of the invention are to provide a process of and apparatus for providing at least a partial barrier to moisture vapour transfer through the surface of a material without substantially spoiling the material, a process of and apparatus for removing moisture from a material without substantially spoiling the material, and a process of and apparatus for providing at least a partial barrier to moisture vapour transfer through the surface of a material and for removing moisture from the material without substantially spoiling the material.

Disclosure of Invention According to a first embodiment of this invention there is provided a process of providing at least a partial barrier to moisture vapour transfer through the surface of a material without substantially spoiling the material, said process comprising: subjecting the material to a controlled temperature and humidity environment, said environment being at a temperature and partial vapour pressure of water which do not spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation: WO 96/02153 PCT/AU95/00418 3 irradiating the material in the environment with infra red radiation, said amount of infra red radiation being sufficient to at least partially seal the surface of the material to provide at least a partial barrier to moisture vapour transfer through the surface of the material without spoiling the material; and maintaining the temperature of the environment, and, (ii) the partial vapour pressure of water of said.environment below saturation, whereby the material whereby the material is not spoilt during step According to a second embodiment of this invention there is provided a process for removing moisture from a material without substantially spoiling the material, said process comprising: subjecting the material to a controlled humidity environment, said environment being at a temperature and partial vapour pressure of water which do not spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation; irradiating the material in the environment with an amount of microwave irradiation effective to increase the moisture at the surface of the material whereby the vapour pressure at the surface is greater than the vapour pressure of the environment whereby moisture is transferred from the surface to the environment, wherein the amount of said microwave irradiation is not sufficient to spoil the material; and maintaining the temperature of the environment, and, (ii) the partial vapour pressure of water of said environment below saturation, whereby the material is not spoiled during step said amount of microwave irradiation being sufficient to substantially maintain said vapour pressure at the surface, until a required amount of moisture has been removed from said material, without reducing the surface temperature of the material more than of the wet bulb depression of the environment.

According to a third embodiment of this invention there is provided a process of providing at least a partial barrier to moisture vapour transfer through the surface of a material and for removing moisture from the material without substantially spoiling the material, said process comprising: providing at least a partial barrier to moisture vapour transfer through the surface of a material without substantially spoiling the material, said process comprising:

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WO 96/02153 PCT/AU95/00418 4 subjecting the material to a controlled temperature and humidity environment, said environment being at a temperature and partial vapour pressure of water which do not spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation; irradiating the material in the environment with infra red radiation, said amount of infra red radiation being sufficient to at least partially seal the surface of the material to provide at least a partial barrier to moisture vapour transfer through the surface of the material without spoiling the material; and maintaining the temperature of the environment, and, (ii) the partial vapour pressure of water of said environment below saturation, whereby the material whereby the material is not spoilt during step and removing moisture from a material without substantially spoiling the material, said process comprising: subjecting the material to a controlled humidity environment, said environment being at a temperature and partial vapour pressure of water which do not spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation; irradiating the material in the environment with an amount of microwave irradiation effective to increase the moisture at the surface of the material whereby the vapour pressure at the surface is greater than the vapour pressure of the environment whereby moisture is transferred from the surface to the environment, wherein the amount of said microwave irradiation is not su!icient to spoil the material; and maintaining the temperature of t:l environment, and. (ii) the partial vapour pressure of water of said environment below saturation, whereby the material is not spoiled during step said amount of microwave irradiaion being :,ufficient to substantially maintain said vapour pressure at the surface, until a required amount of moisture has been removed from said material, without reducing the surface temperature of the material more than of the wet bulb depression of the environment.

Advantageously in the process of the first or third embodiments step comprises:

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WO 96/02153 PCT/AU95/00418 simultaneously or sequentially irradiating the material in the environment with infra red radiation and microwave irradiation, said amount of infra red radiation being sufficient to at least partially seal the surface of the material to provide at least a partial barrier to moisture vapour transfer through the surface of the material without spoiling the material, and said amount of microwave irradiation being sufficient to cause a slight positive vapour pressure within the material to prevent the material from deflating, wherein the amount of said microwave irradiation is not sufficient to spoil the material.

Typicah'y in the process of the first or third embodiments step comprises: subjecting the material to a controlled pressure, temperature and humidity environment, said environment being at a said environment being at a pressure which does not spoil the material.

Typically in the process of the second or third embodiments: said amount of microwave irradiation being sufficient to substantially maintain said vapour pressure at the surface, until a required amount of moisture has been removed from said material, without reducing the surface temperature of the material more than of the wet bulb depression of the environment.

More typically in the process of the second or third embodiments: said amount of microwave irradiation is sufficient to substantially maintain said vapour pressure at the surface, until a required amount of moisture has been removed from said material, without substantial reduction of the surface temperature of the material.

Typically in the process of the second or third embodiments step comprises: subjecting the material to a controlled temperature and humidity environment, said environment being at a temperature and partial vapour pressure of water which do not spoil the material, and. in which the partial vapour pressure of water of said environment is below saturation: More typically in the process of the second or third embodiments step comprises: subjecting the material to a controlled pressure and humidity environment, said environment being at a pressure, temperature and partial vapour pressure of water which do not spoil the material, and. in which the partial vapour pressure of water of said environment is below saturation.

,LI~ II WO 96/02153 PCT/AU95/00418 6 Even more typically in the process of the second or third embodiments step (a) comprises: subjecting the material to a controlled pressure, temperature and humidity environment, said environment being at a pressure, temperature and partial vapour pressure of water which do not spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation.

Typically in the process of the second or third embodiments in step the temperature of the surface of the material is substantially the same as the dry bulb temperature of the environment.

According to another embodiment of this invention there is provided a process of providing at least a partial barrier to moisture vapour transfer through the surface of a material without substantially spoiling the material, said process comprising: subjecting the material to a controlled temperature and humidity environment, said e.vironment being at a temperature which is less than that which would spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation; irradiating the material in the environment with infra red radiation, said amount of infra red radiation being sufficient to at least partially seal the surface of the material to provide at least a partial barrier to moisture vapour transfer through the surface of the material without burning, cooking, or causing surface damage io the material so as to spoil the material; and simultaneously maintaining the temperature of the environment, and, (ii) the partial vapour pressure of water of said environment below saturation, whereby the material does not burn, cook or incur surface damage during step so as to spoil the material.

Typically step comprises: simultaneously or sequentially irradiating the material in the environment with infra red radiation and microwave irradiation, said amount of infra red radiation being sufficient to at least partially seal the surface of the material to provide at least a partial barrier to moisture vapour transfer through the surface of the material without burning, cooking, or causing surface damage to the material so as to spoil the material, and said amount of microwave irradiation being sufficient to cause a slight positive vapour -I WO 96/02153 PCT/AU95/00418 7 pressure within the material to prevent the material from deflating, wherein the amount of said microwave irradiation is not sufficient to remove a substantial amount of moisture from the material, burn, cook, or cause surface damage to the material so as to spoil the material.

The material may be irradiated sequentially once or a plurality of times, e.g. 2-10,000, more typically 2 to 5,000, even more typically 2 to 1,000, yet even more typically 2- 100 and even more typically 2 to 10 (or even more typically 2 to 50, 2 to 25, 5 to times).

Typically in the step comprises: subjecting the material to a controlled pressure, temperature and humidity environment, said environment being at a temperature which is less than that which would spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation.

According to a further embodiment of this invention there is provided a process for removing moisture from a material without substantially spoiling the material, said process comprising: subjecting the material to a controlled humidity environment, said environment being at a temperature which is less than that which would spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation; irradiating the material in the environment with an amount of microwave irradiation effective to increase the moisture at the surface of the material whereby the vapour pressure at the surface is greater than the vapour pressure of the environment whereby moisture is transferred from the surface to the environment, wherein the amount of said microwave irradiation is not sufficient to spoil the material; and simultaneously maintaining the temperature of the environment, and, (ii) the partial vapour pressure of water of said environment below saturation, whereby the material is not spoiled during irradiation of the material in the environment with microwave irradiation; said amount of microwave irradiation being sufficient to substantially maintain said vapour pressure at the surface, until a required amount of moisture has been removed from said material, without reducing the surface temperature of the material more than of the wet bulb depression of the environment.

ill WO 96/02153 PCT/AU95/00418 8 Typically said amount of microwave irradiation being sufficient to substantially maintain said vapour pressure at the surface, until a required amount of moisture has been removed from said material, without reducing the surface temperature of the material more than 30% of the wet bulb depression of the environment.

More typically, said amount of microwave irradiation is sufficient to substantially maintain said vapour pressure at the surface, until a required amount of moisture has been removed from said material, without substantial reduction of the surface temperature of the material.

Even more typically the surface temperature of the material is reduced from a% to b% of the wet bulb depression of the environment where a is selected from the group consisting of a value presented in the column headed in Table A* below at one of entries 1-20, and b is selected from the group of the values presented in the column headed adjacent the corresponding entry.

Table A* Entry a b 1 0 0.5, 0.75, 1, 1.5, 2. 2.5, 3, 3.5, 4, 5, 7.5, 10, 25. 30, 35, 40. 45, 2 0.5 0.75, 1. 1.5, 2, 2.5, 3, 3.5, 4, 5, 7.5, 10, 15, 30. 35. 40. 45. 3 0.75 1, 1.5, 2. 2.5, 3. 3.5, 4, 5, 7.5, 10, 15, 20, 25, 40, 45, 4 1 1.5, 2.2.5, 3, 3.5 4 5, 7.5, 10. 15, 20, 25, 40, 45, 1.5 2, 2.5, 3. 3.5. 4. 5. 7.5. 10, 15, 20, 25, 30, 35, 6 2 2.5, 3 3.5, 4. 5, 7.5, 10, 15. 20. 25, 30, 35, 7 8 9 2.5 3 3, 3.5. 5. 7.5. 10, 15, 20. 25. 30, 35. 40, 4.5, 3.5, 4. 5. 7.5. 10, 15, 20, 25, 30. 35, 40, 45, I I 4. 5. 7.5. 10. 15. 20. 25. 30. 35. 40, 45, I 1 WO 96/02153 PCT/AU95/00418 4 5. 7.5. 10. 15, 20. 25, 30. 35. 40. 45, 11 5 7.5, 10. 15,20, 25. 30. 35. 40. 45, 12 7.5 10, 15, 20. 25. 30. 35, 40, 45, 13 10 15, 20, 25, 30, 35, 40, 45, 14 15 20 25. 30, 35, 40, 45. 20 25. 30, 35, 40, 45, 16 25 30, 35, 40, 45, 17 30 35, 40, 45, 18 35 40, 45. 19 40 45. 45 Typically step comprises: subjecting the material to a cuntrolled temperature and humidity environment, said environment being at a temperature which is less than that which would spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation.

Step may comprise: subjecting the material to a controlled pressure and humidity environment, said environment being at a temperature which is less than that which would spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation.

Step may comprise: subjecting the material to a controlled pressure, temperature and humidity environment, said environment being at a temperature which is less than that which would spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation.

Typically the temperature of the surface of the material is substantially the same as the dry bulb temperature of the environment.

Typically step is preceded by: I I L d I WO 96/02153 PCT/AU95/00418 preparing the material in a suitable form for processing by the process of the first or third embodiments; and (II) heating or cooling the material of to a preselected temperature said temperature being less than that which would spoil the material and being equal to or less than the temperature of step Typically step is preceded by: preparing the material in a suitable form for processing by the process of the second embodiment; and (11) heating or cooling the material of to a preselected temperature said temperature being less than that which would spoil the material and being equal to or less than the temperature of step Typically step is followed by: optionally cooling the material; sterilising the material; and optionally packaging the material.

In the preferred form a microwave sterilisation process is combined with packaging by the use of microwaveable packaging materials suitable for stable long shelf life food products. In another preferred process the sterilisation process is carried out as part of step followed by a cooling process if required prior to packaging in controlled atmosphere packaging materials commonly used in the food packaging industry.

According to another aspect of the invention there is provided as an integral part of the method of production a process for end product sterilisation by microwave radiation. In the preferred embodiment in the invention the sterilisation stage is carried out as an integral part of the final production stage immediately prior to packaging but sterilisation can equally be carried out as an integral part of the product packaging stage by the use of microwaveable long shelf life packaging materials in common use in the industry.

According to a preferred form of the invention there is provided a process of production incorporating the preferred process stages of: starting material preparation and process presentation delivery stage; II I le- WO 96/02153 PCT/AU395/00418 1 1 An initial processing stage in which thie presented starting material is processed under a controlled temperature andi pressure environment (atmospheric or vacuum) using a combination of infra-red radiant heating and microwave irradiation and vapour extraction/condensing closed cycle heat pump drying and controlled product temperature; A final cooking/drying/puffing/foaming/processing stage as applicable to meet the end product specifications and incorporating continuously variable product feed back controlled microwave irradiation in a temperature and pressure controlled (atmospheric or sub-at"' ,eric) environment complete with vapour extraction/condensing system and e, ission control; Product microwave sterilisation and packaging and cooling stage.

According to a fourth embodiment of this invention there is provided an apparatus for providing at least a partial barrier to moisture vapour transfer through the surface of a material without substantially spoiling the material, said apparatus comprising: means for subjecting the material to a controlled temperature and humidity environment, said environment being at a temperature and partial vapour pressure of water which do not spoil the material, and. in which the partial vapour pressure of water of said environment is below saturation; means for irradiating the material in the environment with infra red radiation, said amount of infra red radiation being sufficient to at least partially seal the surface of the material to provide at least a partial barrier to moisture vapour transfer through the surface of the material without spoiling the material; and means for maintaining the temperature of the environment, and, (ii) the partial vapour pressure of water of said environment below saturation, whereby the material whereby the material is not spoiled.

According to a fifth embodiment of this invention there is providled an apparatus for removing moisture from a material without substantially spoiling the material, said apparatus comprising: means for subjecting the material to a controlled humidity environment, said environment being at a temperature and partial vapour pressure of water which do not spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation: aa.arr- lmrr l ~-l---arsl rrr~.- WO 96/02153 W CIVAU95/004 I 8 12 means for irradiating the material in the environment with an amount of microwave irradiation effective to increase the moisture at the surface of the material whereby the vapour pressure at the surface is greater than the vapour pressure of the environment whereby moisture is transferred from the surface to the environment, wherein the amount of said microwave irradiation is not sufficient to spoil the material; and means for maintaining the temperature of the environment, and, (ii) the partial vapour pressure of water of said environment below saturation, whereby the material is not spoiled; said amount of microwave irradiation being sufficient to substantially maintain said vapour pressure at the surface. unltil a required amount of moisture has been removed from said material, without reducing the surface temperature of the material more than of the wet bulb depression of the environment.

According to a sixth embodiment of this invention there is provided an apparatus for providing at least a partial barrier to moisture vapour transfer through the surface of a material and for removing moisture from the material without substantially spoiling the material, said apparatus comprising in combination: an apparatus for providing at least a partial barrier to moisture vapour transfer through the surface of a material without substantially spoiling the material, said apparatus for providing at least a partial barrier to moisture vapour transfer comprising: means for subjecting the material to a controlled temperature and humidity environment, said environment being at a temperature and partial vapour pressure of water which do not spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation: means for irradiating the material in the environment with infra red radiation, said amount of infra red radiation being sufficient to at least partially seal the surface of the material to provide at least a partial barrier to moisture vapour transfer through the surface of the material without spoiling the material: and means for maintaining the temperature of the environment, and, (ii) the partial vapour pressure of water of said environment below saturation, whereby the material whereby the material is not spoiled: and ILL ~I WO 96/02153 PCT/AIU5/00418 13 apparatus for removing moisture from a materiil thout substantially spoiling the material, said apparatus for removing moisture comilpnsing means for subjecting the material to a controlled humidity environment, said environment being at a temperature and partial vapour pressure of water which do not spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation: means for irradiating the material in the environment with an amount of microwave irradiation effective to increase the moisture at the surface of the material whereby the vapour pressure :t the surface is greater than the vapour pressure of the environment whereby moisture is transferred froml the surface to the environment, wherein the amount of said microwave irradiation is not sufficient to spoil the material; and means for maintaining the temperature of the environment, and, (ii) the partial vapour pressure of water of said environment below saturation, whereby the material is not spoiled; said amount of microwave irradiation being sufficient to substantially maintain said vapour pressure at the surface, until a required amount of moisture has been removed from said material, without reducing the surface temperature of the material more than of the wet bulb depression of the environment.

Advantageously in the apparatus of fourth or sixth embodiments comprises: means for simultaneously or sequentially irradiating the material in the environment with infra red radiation and microwave irradiation, said amount of infra red radiation being sufficient to at least partially seal the surface of the material to provide at least a partial barrier to moisture vapour transfer through the surface of the material without spoiling the material. and said amount of microwave irradiation being sufficient to cause a slight positive vapour pressure within the material to prevent the material from deflating, wherein the amount of said microwave irradiation is not sufficient to spoil the material.

Typically in the apparatus of fourth or sixth embodiments comprises: means for subjecting the material to a controlled pressure, temperature and humidity environment, said environment being at a said environment being at a pressure which does not spoil the material.

I _1 WO 96/02153 PCT/AU95/00418 14 Typically in the apparatus of fifth or sixth embodilmenIs comprises: means for subjecting the material to a controlled temperature and humidity environment, said environment being at a temperature and partial vapour pressure of water which do not spoil the material, and. in which the partial vapour pressure of water of said environment is below saturation; Typically in the apparatus of fifth or sixth embodiments comprises: means for subjecting the material to a controlled pressure and humidity environment, said environment being at a pressure, temperature and partial vapour pressure of water which do not spoil the material. and. in which the partial vapour pressure of water of said environment is below saturation.

Typically in the apparatus of fifth or sixth embodiments comprises: means for subjecting the material to a controlled pressure, temperature and humidity environment, said environment being at a pressure. temperature and partial vapour pressure of water which do not spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation.

According to another embodiment of this invention there is provided an apparatus for providing at least a partial barrier to moisture vapour transfer through the surface of a material without substantially spoiling the material, said apparatus comprising: means for subjecting the material to a controlled temperature and humidity environment, said environment being at a temperature which is less than that which would spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation; means for irradiating the material in the environment with infra red radiation, said amount of infra red radiation being sufficient to at least partially seal the surface of the material to provide at least a partial barrier to moisture vapour transfer through the surface of the material without burning, cooking, or causing surface damage to the material so as to spoil the material: and means for simultaneously maintaining the temperature of the environment, and, (ii) the partial vapour pressure ol" water of said environment below saturation, whereby the material is not burnt cooked or surface damaged during irradiation of the material in the environment with infra red radiation so as to spoil the material, said r I WO 96/02153 PCT/AU95/00418 means for irradiating the material in the environment with infra red radiation being operatively associated with said means for simultaneously maintaining the temperature of the environment, and, (ii) partial vapour pressure of water of said environment below saturation whereby the material is not burnt cooked .r surface damaged during irradiation of the material in the environment with infra red radiation so as to spoil the material.

Typically and comprise: means for simultaneously or sequentially irradiating the material in the environment with infra red radiation and microwave irradiation, said amount of infra red radiation being sufficient to at least partially seal the surface of the material to provide at least a partial barrier to moisture vapour transfer through the surface of the material without burning. cooking, or causing surface damage to the material so as to spoil the material, and said amount of microwave irradiation being sufficient to cause a slight positive vapour pressure within the material to prevent the material from deflating, wherein the amount of said microwave irradiation is not sufficient to substantially remove moisture from the material. burn. cook, or cause surface damage to the material so as to spoil the material: and means for simultaneously maintaining the temperature of the environment, and, (ii) the partial vapour pressure of water of said environment below saturation, whereby the material does not burn, cook, or experience surface damage so as to spoil the material during simultaneous irradiation of the material in the environment with infra red radiation and microwave irradiation, said means for simultaneously or sequentially irradiating the material in the environment with infra red radiation and microwave irradiation being operatively associated with said means for simultaneously maintaining the temperature of the environment, and, (ii) the partial vapour pressure of water of said environment below saturation, whereby the material does not burn, cook, or experience surface d(amage so as to spoil the material during simultaneous irradiation of the material in the environment with infra red radiation and microwave irradiation.

Typically comprises: means for subjecting the material to a controlled pressure, temperature and humidity environment, said environment being at a temperature which is less than that

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WO 96/02153 PCT/AU95/00418 Ib which would spoil the material. and. in which the partial vapour pressure of water of said environment is below saturation.

According to a further embodiment of this invention there is provided an apparatus for removing moisture from a material without substantially spoiling the material, said apparatus comprising: means for subjecting the material to a controlled humidity environment, said environment being at a temperature which is less than that which would spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation; means for irradiating the material in the environment with an amount of microwave irradiation effective to increase the moisture at the surface of the material whereby the vapour pressure at the surface is greater than the vapour pressure of the environment whereby moisture is translerred Ifrom the surface to the environment, wherein the amount of said microwave irradiation is not sufficient to spoil the material; and means for simultaneously maintaining the temperature of the environment, and, (ii) the partial vapour pressure of water of said environment below saturation whereby the material is not spoilt during irradiation of the material in the environment with microwave irradiation, said means for irradiating the material being operatively associated with said means for simultaneously maintaining the temperature of the environment, and, (ii) the partial vapour pressure of water of said environment below saturation whereby the material is not spoilt during irradiation of the material in the environment with microwave irradiation; said amount of microwave irradiation being sufficient to substantially maintain said vapour pressure at tlie surfce, until a required amount ol moisture has been removed from said material, without reducing the surface temperature of the material more than of the wet bulb depression of the environment.

Typically said amount of microwave irradiation being sufficient to substantially maintain said vapour pressure at the surface, until a required amount of moisture has been removed from said material, without reducing the surface temperature of the material more than 30% of the wet bulb depression of the environment.

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WO 96/02153 PCT/AU95/00418 17 More typically, said amoun of microwave irradiation is su fficient to substantially maintain said vapour pressure at the surface, until a required amount of moisture has been removed from said material. without substantial reduction of the surface temperature of the material.

Even more typically the surface temperature of the material is reduced from a% to b% of the wet bulb depression of the environment where a is selected from the group consisting of a value presented in the column headed in Table A above at one of entries 1-20, and b is selected from the group of tile values presented in the column headed adjacent the corresponding entry.

Typically comprises: means for subjecting the material to a controlled temperature and humidity environment, said environment being at a temperature which is less than that which would spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation.

More typically may comprise: means for subjecting the material to a controlled pressure and humidity environment, said environment being at a temperature which is less than that which would spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation.

Typically comprises: means for subjecting the material to a controlled pressure, temperature and humidity environment, said environment being at a temperature which is less than that which would spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation.

Typically includes or in addition to there is: means for preparing the material in a suitable forn for processing; and (11) means for heating or cooling the material of to a preselected temperature said temperature being less than that which would spoil the material and being equal to or less than the temperature of

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WO 96102153 PCT/AU95/00418 18 Typically includes or in addition to there is: means tor preparing the material in a suitable form for processing; and (II) heating or cooling the material of to a preselected temperature said temperature being less than that which would spoil the material and being equal to or less than the temperature of Typically includes or in addition to there is: optionally means for cooling the material: means for sterilising the material: and optionally means for packaging the material.

In the preferred form a microwave sterilisation process is combined with packaging by the use of microwaveable packaging materials suitable for stable long shelf life food products. In another preferred process the sterilisation process is carried out as part of step of the second or third embodiments followed by a cooling process if required prior to packaging in controlled atmosphere packaging materials commonly used in the food packaging industry.

The processes of the invention may be carried out under continuous environmental and product control and do not incorporate convection heating, cooking or baking or any conventionally understood baking process. The infra red radiation used in the processes and apparatus of the present invention do not heat the atmosphere through which they pass. For heat transfer they rely on the absorption of their radiant energy by the surface of the product which is being radiated. Infra-red rays have only a very minor penetration through the surface of most products. The heat transfer characteristics and efficiency can be calculated by the application of recognised engineering formulae.

In the methods of the second and third embodiments and apparatus of the fifth and sixth embodiments "puffing" of some food products including cheeses can be achieved by microwave processing without recourse to the conventional baking process and high air temperatures or the use of leavening agents. This is due to the fact that suitable internal vapour pressures can be generated within the product by controlling the intensity of microwave energy and the processing time. Further by controlling the temperature of the product by microwave energy and controlling the processing atmosphere temperature. pressure and humidity the puffing process can be further controlled due to WO 96/02153 PCTAU95100418 19 the surface conditioning of the product. It should be noted that in the invention the processing atmosphere will be maintained at a temperature not exceeding tQvie product temperature and no sensible heating energy passes from the air to the product. This is precisely the reverse of convection cooking.

Some cheeses require additional "surface conditioning" to increase the extent of puffing. This is typically achieved by an infra-red radiant heating process which again eliminates the need for heating energy to pass from the processing atmosphere into the product as would be the case with convection baking.

The use of infra-red radiation in conjunction with microwave processing and integrated temperature control of the product and the processing atmospheric conditions, enables surface conditioning of the product to be achieved without a "cooking and baking step.

The processing steps defined in the embodiments of the invention relate to continuous flow processing. The steps are sequential but may be operated in part or in whole sequentially or simultaneously depending on the specific processing application. The processing apparatus of the invention provides for this flexibility of operation.

The inclusion of electro-magnetic infra-red radiant heating in combination with microwaves and the integrated control of product temperature and the processing atmospheric pressure, temperature and humidity in the first embodiment is not a convection heating, cooking or baking step.

Using the processes of the invention it is possible in many instances to establish and maintain optimum processing conditions for the repetitious commercial production of high quality snack foods, such as for example. the range of cheese and cheese based products referred to in this invention.

Factors which influence the processing of specific products include: The physical form of the product which is presented for processing, including for example, the unit surface area versus product volume and mass, product consistency, texture, colour and aroma and trmin and temperature of the presented product and conveying platform characteristics The chemical composition of the presented product and the compatibility of the ingredients of a product mixture for simultaneous processing and quality control or otherwise requiring independent pre-treatment.

WO 96/02153 WCT/AU95/004 18 The environment in which the product is to be processed, for example, in a natural ambient atmospheric pressure environment having no control of dry bulb and wet bulb temperature or alternatively in a'controlled ambient environment in which the dry bulb and wet bulb temperatures are controlled or alternatively in a fully controlled environment in which the dry bulb and wet bulb temperatures and operating pressure is controlled at atmospheric pressure or sub-atmospheric (vacuum) pressure as determined principally by the product temperature sensitivities.

The impact of the selected form of process heating and drying at each stage of the production process, including for example, the process impact on the surface condition of the product and its internal structure, the volatilisation of aromatic compounds and the formation and control of product puffing and progressive rate of removal of the product water vapour and product sterilisation to meet the final product specifications on a continuous process basis.

In the processes of the invention the relationship between the process environment temperature and vapour pressure and the product surface temperature and surface vapour pressure is an important relationship and influencing factor in product processing quality control and energy efficiency of the production process.

Puffing of products during processing, as for example, in the production of some cheese products described in this invention, can he induced and controlled by the process of the invention having regard to such factors as for example: the surface area of the presented product with respect to the volume and mass of material contained.

the method and form and physical and chemical properties and ingredients of the material as presented for processing including for example temperature, viscosity if applicable, containment if any, surface area available for sensible heat transfer and moisture evaporation and starting moisture content.

the processing ambient air dry bulb and wet bulb temperatures and operating pressure throughout the manufacturing process.

the relationship between the processing ambient air conditions noted in and the product moisture content and surface temperature and su ace vapour pressure throughout the production process.

I WO 96102153 5IPCT/AU9/00418% 21 the processing potential for the induced formation of a product surface skin or preferably a light glazing to increase the surface permeability resistance to the transfer or product vapours and hence in one aspect assist in the control of puffing.

the respective processing sub-system time/performance proliles and performance characteristics.

Typically the apparatus of the invention includes a surface temperature sensor a fibre optic temperature sensing device or an infra red sensing device) to measure the surface temperature of the material.

The microwave electromagnetic heating frequencies typically used in the processes of the invention 896, 915, 922 and 2450MHz permitted deviations which have been allocated by international agreement for this purpose. More typically the microwave frequency used is in the range 915 25 to 22.125 125 megacycles/second more typically 915 25 to 7,500 50 megacycles/second.

The preferred frequency is 2450MHz having regard to the process requirements for product penetration, energy intensity capacity, operational control flexibility and high on-line production availability and maintenance.

According to a further aspect of the preferred embodiments of the present invention there is provided a means whereby a microwave energy heating system incorporated in the production process described in the second embodiment is used in whole or in part to control the product internal and surface temperature to a pre-determined processing temperature which may for example be controlled to the wet bulb temperature of the ambient air/vapour or held at the dry bulb temperature of the ambient air/vapour or at any pre-determined surface temperature above the ambient wet bulb temperature but preferably not higher than 100"C and more preferably lower than 80 0 C and most preferably lower than 60 0

C.

It should be appreciated that the invention has industrial applicability to a wide variety of food manufacturing processes where the preferred embodiments of the invention may be used in part or in whole or as independent processing sub-systems or as a combination of processes operating sequentially or simultaneously depending on the specific processing application.

PIII I WO 96102153 PC/rAUI95/04 18 In its preferred form for the production of cheese and cheese based products for example, there is provided in the starting material preparation stage fully controllable means for: receiving hot viscous cheese from a cheese processing cooker or other prior processing plant or storage facility at a temperature in the range 400 to 90°C and preferably in the range 40° to Receiving cold pieces or links of processed or other cheeses or cheese mixtures which have been pre-formed or sliced or diced or cut or pressed to a predetermined size and shape and/or weight relative to the end product specification.

The preparation of the starting material into its preferred form for subsequent processing and including for example such preparation processes as grinding, mixing, adding of condiments, emulsifiers, flavours, and other additives in standard proportions in accordance with the recipe of the particular product and blended for uniformity of the starting material for presentation for production processing.

The controlled delivery and presentation for processing of the prepared starting material for example in extruded viscous cheese form as continuous strips or drops or other shapes or as cold links of processed cheese or other cheeses and cheese mixtures all to predetermined size. shape and unit weight deposited onto a microwave transparent conveyor belt or other conveying system designed to suit the subsequent processing energy system and the characteristics of the product material and end product specifications and quality control.

In its preferred form the starting material delivery and presentation sub-system described in above there is provided a means for product heating and cooling to enable the temperature of the product to be automatically controlled to an adjustable pre-determined temperature of the product at the point of presentation for processing by the processes of the first and/or second embodiments.

According to a further aspect of the preferred embodiment of the present invention there is provided a means whereby the dry bulb and wet bulb temperatures of the recirculating ambient air/vapour mixture in the product processing chamber in the preferred form of the method of production described in the second embodiment is controllable relative to the surface temperature of the product being processed such that rJII WO 96/02153 PCT/AU95/00418 23 the drying process is engineered to operate ais ian adinbatic or isothermal process or at any pre-determined combined process between these two specific conditions.

The processes of the invention are suited 10 the manufacture of a wide range of food products and in particular snack food products and consumer shelfl products and for the processing of agricultural products having similar processing requirements. Examples include snack food products including puffed snack food products and dried products from the following starting materials: All-natural cheeses and processed cheese (which may include other additives such as carbohydrates, cereals, proteins, meats, fruits, nuts, minerals, vegetables. colouring, flavouring, sodium and non-sodium emulsifiers, condiments. eggs, spices. and smallgoods. and other additives. may be included), including low fat cheeses and cheese based mixtures and including for example all cheddars, Colby, Swiss processed cheese, condiments, spices, marine algae, marine plants including seaweed, protein sources such as egg protein, soy protein, milk protein, gluten or caseinate which may optionally be emulsified with plant or animal fat or oils such as soybean, sunflower, peanut, olive, canola, safflower or palm oil, together with other components and water, cereals including wheat, rye, corn, rice, millet, sorghum, maize, barley and oats, nuts including peanuts, almonds, cashews, hazel nuts, maccadamia nuts, walnuts, flesh of prawns, shrimps, yabbies, Balmain bugs, pippies, flesh of turtles, flesh of tortoises, eels. octopus, id, squidflesh of lobsters, flesh of crayfish, flesh of crabs, marine mammals and fish including hardiheads, white bait, mullet, sardines, salmon. tuna, trout, bream, black fish, flathead, tailer, John Dory, schnapper, trevally, sweep, shark. garfish, pike, leatherjacket, wrasse, mulloway, dolphin fish, kingfish, blennies, gobies, toad fish and other like fish, plant proteins and/or polypeptides from rice, barley, out, rye, corn. wheat, animal meats and poultry including, beef, chicken, pork. rabbit and turkey, flowering plants such as rose, iris, carnation, daffodil. lily. vegetables such as cabbage, cauliflower, peas, beans, such as soyabeans, lentils, mung beans. lima beans, kidney beans, adzuki beans, and broad beans, broccoli. brussel sprouts, peanuts. chickpeas, asparagus, soya extracts, natural processed dairy products, fruits including apples, bananas, apricots, plums, cherries, pears, pineapple. vine products including grapes and dates, fruit skins including orange and mandarin skins, and fruit seeds including grape seeds, berries, herbs spices raw material, vegetable produce natural semi-processed, oil seed, seeds, nodular and granular products, agricultural produce waste products: chemical WO 96/02153 WOICrIAU95/04 I t0 24 compound recovery-citrus fruits, grape waste. paper pulp products, wood chips, wood shavings, sawdust, dehydration of chemical ipowdelr comlpounds. honey. treacle, sugar cane and molasses including sugar beet process molasses, tor example.

The processes of the invention are capable of processing a wide range of starting materials which typically are cheese and cheese based mixed products which may vary in moisture content from-20-60% and in 'at content from 15-55% in dry matter. The method of production is not limited to these typical analyses and would satisfactorily process starting materials having higher or lower moisture and fat contents than those indicated, the main variable in the process being the product residence time.

According to another aspect of the invention there is provided a range of snack food products manufactured from natural cheeses or processed cheeses or cheese based mixed ingredient starting materials and including for example such ingredients and additives as fruits, vegetables, cereals, berries, nuts, meats, eggs, smallgoods and herbs and spices to provide added flavour and/or nutritional value and variety of products when prepared by a process of the invention.

According to another aspect of the invention there is provided a range of manufactured wholesome cheese based snack food products characterised by their dry, crisp, crunchy, open cellular properties and high nutritional and energy value and palate appeal when prepared by a process of the invention.

By way of example only, these products include: A range of cheese based. dry. crisp, crunchy snack food products for example in the form of biscuits, crackers and wafers of various sizes, shapes and flavours, and of full cheese or mixed cheese and other ingredients content.

A range of dry, crisp, crunchy snack food products for example in the form of snaps, curls, twists, crisps. balls, chips and sticks of various flavours and of full cheese or mixed chees, and other ingredients content.

A range of light puffed or foamed snack lood lprodlucts in the form for example of cookies, cakes, puffs, buns and loaves of various flavours and of full cheese or more preferably mixed cheese and other ingredients content.

According to another aspect of the invention there is provided a range of long shelf life snack food products as described above for example and pre-processed and sterilised 1. I I 1 WO 96/02153 PCT AU95/00418 and packaged in microwaveable packaging ready for final home microwave heating for serving as hot savoury snack foods.

According to another aspect o' the invention there is provided a range for example of stable long shelf life, dried, ground, packaged and sterilised cheese and cheese based mixed ingredients for use as flavouring and cooking additives, spiced cheese condiments and cheese fruit and cheese nut additives, fillings and spreads when prepared by a process of the invention.

According to another aspect of the invention there is provided a process of the invention in which the moisture content of the processer' ma.erial is dried to a predetermined specification requirement which is determined for the particular product having regard to shelf life, stable physical condition and consumler appeal but typically being between 1.5% and The process is not limited to processing within this range and higher or lower moisture contents are provided.

Also provided is a process of production and a process suitable for the manufacture of vegetable and animal fat and protein based food products which exhibit similar processing requirements to that of the cheese based products covered by this invention.

TABLE A: Examples of Types of Product Applications Typical Physical Form of Input Product Liquid Viscuus Natural Sliced Diced Granular Extruded fori Natural processed cheeses and dairy products Meats. fish.

V

poultry Fruits, berries. v vine products Herbs. condiments spices raw material i WO 96/02153 WO 96/2153 T/AU95/0041~8 Veg".etable produce naturlf $m-fcse indlud ing marine algae and plant, produICtS Cereal grains, oil seed, nu~ts, seeds.

nodular and granular proiducts AgricultUratl/ produLce waSte products: chemnical compound recovery-citrus truitS. grapHIe waste etc.

Paper pulp prOductS. woodI chips. wood shavings, sawdust Dehydration of chemnical P)owder compounds Sugar cane and Sugar heet process molases WO, 96/02153 WO 9602153PC'IAU9SIOO4I S 27 TABLE B: Expected Maximum Ranges~ of a Number of Process Parameters Prod 11(1 I I IV( 11(3)* t Desig natlo Max Max Nlax Nlax Ilvplc NMa\ NMa.\ Iv MaxMa expect expetct expetct expect all\ e~ec expect expc I)C Ced~ expect ed td ed edL 11aLmuN md edI eI ed ed ratnee ritnie r1AInge rtmeeIZ phficl- tanflte fte raIlyc f'al11 fdve 0- 2- 10- 15- hum111id I- I I tirn I atml 0 C 60 0 C. SOOC 1 20iC t 0 1) 3 0 'It trn.. to toi I Li- humid himidIL Typic 0.9 0. I at 11111id alil MxMax Max Max Typic: Max Max Max Mla,\ Max expect \I expe expec uxct pe1 expect expIIi-CI e~tC expect e~xpect ed ed ed ed attutoS ed ed Ced ed ed malitle iatui.' C III I I V aLu pluericw ie. raneeot raline ranuec ramnIle 4- 20- htiid I I5- oi.5- I I atml I atml 3L 0 C 30)'C 25 0 C 50"C' it\ 9 Qt) I 30L/ Wilatt.. to, to IL) htiinid hutmid Typic 0.9Q 0. hit 9LCI itv itv all", IM m III humuid latml it), Mutx Max Max Max TyIc Max Max Max Max Max expect expect expect eIxpect ally expectl expecltexpecl expect e~xpect ed ed ed ed Itmlt~s td L e d td ed ed raiw ranuv~ t'aum.v itit~ Ihf I Illee, iailm1-e male.1 UV Ia 1e 4- 4- I5- lI- huitid to- 2- 0.5-1 t atml I atml 300C 30i'C 5L0"C 7Lt"C tI I.t\ Q( 30t l/ atml.. tII to ILU- huiid hlumlid Typic. U.

9 at 0. lat 901/ iv t alk I III III aii) WO 96/02153 WO 9602153PC'T/AU95/00418 NMax expect ed ran cc 0

C

M ax cxilpei ed rancI'e 60 0

C

Niax" cx pee tii rangeI! I5- 8011C M ax ex peev eLI m'acle 15- I 000'C humid I) 5 111 LIl lI LI it\ N'ax M ax cxpect expect vJ ed 309 huklillid l h iliii It\ I[\ Ma.\ M ax C eL I CLx1CI 0.5-I I atnn Tpc 0.9 ait ill M ax expect

CLI

ran cc I atml to)- 0. imt Ill MIax expct aed 0

C

M ax expect ce I 40 0

C

M ax expect eLI raIILce I5S-

SOIC

MIax expect

CLI

I'ai c I5- 100t1 C aliiild phe11lid itv I I huiimid it\ M~ax expect

I-

expectl cd 0.5-I kit iii.

Typic atl In ed ra n cc I aitiii toi 0.9 atml Max expect ed rangcc I Him toi- 0. 1lat Ill Max expect

CLI

Max expetct rarii.! 45 0

C

Max expect

CLI

r1012 ma x to- 12LI lypic I 0_ kit lii M~ax hiumid NMax vxp~ 30 V, 1111111LI its' MIax all\ I attnl Ma x expect:

CLI

0.9 atil Max expect e d ran c1Vc I atmI tol 0. 1lat Ill WO 96/02153 WO 9602153PCT/AU95/004 18 Max\ Ox pect cii ran cc 0- 0

C

Max elxperct cii ranvc 5I- 70"C ex pect aed 80C) bLid 5 1h1 111 L 9)0E-1 Its haiUllIi ivy 2- 30 V ILIlt ii Ii' Max cil 0.5-1 Ty'pic allY I I ain ill 0.9 atilt NMax expect t::i range I atilt to- 0. Ill Ill M ax expect cii ran,-,e 0_- 9UIC NM ax expect ra nue 4- M ax cxpect tIi rance- 10(tm-ct expcect Itt Typic ;1I.

phctuc Its I 0_ 1) 0C/I hun.1idi its Niax cx ~cct cii ran cc it,.

liLiflhtil it) M ax 30 Qt hu'lu, Its Max ran w, at Ill..

Typic all\, I illi M'lax cx pect CIi 01.9 Htimi Max expect cii ranllce I atill to)- 0. Itat Ill Max expect cii ran cc 0- 950C Ma ax expect cii ra ncle 4- 90 0 c, Max expect tii ran cc I10- 90 0

C

Max Typic cii atita.

120'C its' It0- IILItiLI Its expect It Max expe-ct eii 30 c/ Max expect Max expet cii rangec I attn t- Max expect ran cc I attnl tot hLitnIII I TI pc ity Iially I WO 96/02153 PCTAU9SI 04 18 Max Cd ra nuI e Max CX 1p,,:i ed rang~e 10- 600uC MIax expeto 15- 950C Maxl.

v~il'I

CLI

ranuc 25- 1 20"C TyPIC .111) LII Ill IS pheiic hIlnhld It) Cthiinid It'.

90 11twilld M ux 2- 30'li 111111lid ita NI. Lx v cxlI expect expic: xpc d e~i d Ced rL 111111 lane Ifl1e a c: ac In-U 2- I I ati al n Y ~t~q 3 I4 L Ill. I I h t tll I lL~hhd ypic 0,9 UIL LIX 11% III~ I Ltifll HIM l Max expeo ed 0 !ill

JI

#For the list of Table C.

Products (orrespondi no to the Product De,'ip tation refer to columin 2 of TABLE C: Expected Maximum Ranges of a Number of Process Parameters Product P~roduct 1* Designation Natural ptIIce~sed NI ML IV C MaelelLx expected cl~eeLs aLI dii~ iII),il-.tLll'e 0II httlk ieilptati-Hr Lit hu~lk Pro d u ct Ltl I Irn maial II d Lirinug pIICC~i~g- )0'C prIcessing 120'C Meats. f'ish, pIttty.. MLi\ expcted MaIx expected (tiatral ttiilpvralute III hlk temlpeiattire 1)1 hUlk pro cessed) ihLtCILIL Ii gfllitt LIlI duLmrwn ptIocessitg 600C7 Processing I Lluit. hi. I'n LIN eetdN'ax expected P I-OLILI t 1t~t l tenlperittrl II l ha k [Ciniperal ure n t'ha1k Il-occ~sng 00C prcssn 120'C b Hrh. ~tniletts MaIX CXpeteh Max expcted spc, raCC Idw tenIlpe IL tare I) 1111L1k t oea iI t hutlk materi al hIl lertaL dl I n fI'teri LII d Liri nu prot.-.liv I 0 0 C. prccssng I1200C7 WO096/02153 PC T/AU95/00418 \'egelahle prmlmucc NIiNx keXCIed Max expected narturalt Senli telflperaIIII-C IdI bulk telfpeflIILII Ill hulk nulr ti at~a~and pILoce'SS111! 60-C pri wessl ng, I I 0,C r Cereal Lnrins. oil NMat\ e:Xpected Max. expected seed, nuts. seeds. temjperaIluic ut 1111k telipeI"ItLure ot hulk nodular arnd 11.1te-1.11 duLIT1- material duitrn C~a1L~~IIp11 I LI1~ prIwcts"I ii, 600C prolcessing, 120 0

'C

'I ~Actclua Max CNxpecleLl Mtax expected 111I)LdCc WvI.Skc tLII~piX~amvc ofl hulk tel"lipelatulIIIOf hulk pitOIdurCES: chemical Ill11CAtL LlIInI- ma11trial d~u~r CMPUld C Cv provc.SSinl Q) 0 C proicesstiny 15 0

C

citrus frtuits. g.raple waste etc.

Paper pulp Max\ vxps cIed Max expected pro d ucts. \voo d IC m1pera Ill.I l hul1k temperatre o f* bulk chis. oodmatialI' durimnu material duirnnu proicessing 1 Deliyd rat ion of' Max expecd Max expected Chemical plowder tI1ljIIIILIEC of~ hulk temnperaturle of' hulk compt iui~lsiiitlial duL111i material durniu.

pIILe.Iu~ t)C prot.cessin--! 150'C Sutr are nd Max expVCC-Le Matx expected Sugar~ h eel pro1 Ces~s t Ii ila ILIP I IIhLI 1k tempera ture of' bl k ITIIII isses maeral durIil, mal~terial durinu pr1Icessim1, 90,C pr~cesing 130'C +Miji-LjIfjj11 temperatUire Of hulk material (luring processing is typically P 0

C

*Processing Parameters Definitioins (see Tables B a-nd C for parameter entries): Step 1: T(O) Bulk material temperature at entry to Step I T( I) BLrl k tmateriat temnperat ure at e.\t Crom Step I HI)-Processi ng enlv Iron mentI R H P( 1) Processing environment atmlospheric pressuire WO 96/02153 WO 60153PT'/AU95/004 18 32 Step 2: H Processino env'ironment RH P(2 processing, en v ron nient at iospheric pressu re Processing environment DB temperature -Blk material temperature T(2) 2 Surtface temperature of material Step 3: TO3) Processing4 envi ronlment D13 temperature T(3)1 Bulk material temperature T(3 )2 Su rface tcII)lLI* Of pe ra a a .Cmae ru H(3) Processint, environment RH P(3) Processing equipment at mospheric pressure WBD(3) Processing environment DB temperature mlinuLs the processing environment W11 temperalure.

Note: DB dry bulb temperature WBz wet bulb) temnperatuLre RH =relativ I \eliii midit ypecntg Temperature inl deglrees CelSiulS Pressure inl relation to one I) at mosphere.

T( and T(3) have expected maximum temlperatUre ranges as listed in Table B. and and T(3)l have expected maximum temlperature ranges as listed in Table C. Preferred temperatutres or tem ptrat Lire ranges within these ex pectedllmaxi an tim temperature ranoes for each of* these parametcrs are listed in Table D. ThuLs to Choose a particularly preterredl temperature range e"C( f"C Ior at particular T, e is selected fromn the grouIp conSiStillu Ot a value pr-eSentedl in the column headed in Table D below at one or more of' entries 1-25 (where e the minilum temperature listed in Table B for the particlar T) and f is selected Froml the 0group1 Of the values presented inl the COILII1 headed adjacent the corresponding entry (where the mlaximum1.11 temperature listed in Table B for the particular WO 96/02153 PCT/AU95/00418 33 TABLE Temlperaltim- ranglSi 0l' I'iiri rler. 1S T(3)' Entry e f 1 0 5, 10. 15. 20. 25. 3U., 35, 40. 45, 50. 55. 60, 75, 80, 85, 90, 95. 100, 110, 120, 130, 140.

150 2 5 10. 15. 20. 25. 30. 35. 40, 45, 50, 55. 60. 65, 80. 85, 90, 95, 100. 110, )20, 130, 140. 150 3 10 15. 20. 25. 30, 35, 40. 45, 50, 55, 60, 65. 70, 85. 90. 95. 100. 110. 120, 130, 140, 150 4 15 20. 25, 30, 35. 40. 45, 50. 55, 60, 65, 70, 75, 90. 95. 100. 110. 120. 130. 140. 150 2 25, 30, 35. 40, 45, 50. 55. 60, 65. 70, 75, 80, 95, 100, 110, 120. 130, 140, 150 6 25 30. 35. 40. 45. 50. 55, 60, 65, 70, 75. 80, 85, 100. 1 10, 120. 130, 140, 150 7 30 35. 40. 45. 50. 55. 60, 65. 70. 75. 80, 85. 90. 100. 110. 120. 130. 140, 150 8 35 40. 45. 50. 55. 60, 65. 70, 75, 80, 85, 90, 95, 100, 1 10, 120. 130, 140, 150 9 40 45. 50, 55, 60, 65, 70, 75, 80, 85. 90, 95. 100, 110. 120. 130. 140. 150 45 50, 55. 60. 65. 70. 75. 80. 85. 90, 95. 100, 110.

120. 130. 140. 150 11 50 55, 60, 65. 70, 75, 80. 85. 90. 95, 100. 110. 120, 130, 140, 150 12 55 60. 65, 70, 75. 80, 85. 90, 95. 10t0. 1 10. 120. 130, 140. 150 13 60 65. 70. 75. 80. 85. 90. 95, 100. 110. 120. 130, 140, 150 WO 96/02153 W096/2153PCT/AU95/00418 14 65 70. 75, 80, 85. 90. 95. 100. 1 10. 120, 130. 140, 150 70 75, 80. 85. 90, 95. 100. 110, 120. 130. 140, 150 16 75 80, 85 90. 95. IOU. 1 10. 120. 130. 140, 150 17 80 85, 90, 95, 100, 1101. 120, 130, 140, 150 18 85 90. 95. 100, 110, 120. 130, 140. 150 19 90 95, 100, 110, 120. 130, 140, 150 2)09 1.10.1013.1015 100 110. 120. 130. 140. 220 110 120. 130. 140. 23 120 130, 140, 150 24 130 140.150O 140 150 H( H and hav'e expected ma-IXillll mum humidity ranges as listed in Table B.

Preferred hum11idities Or humI~idlity' rn1ge0S wItliiii theL:sC expete imximumlll hum1idity ranges for each of these parameters are listed in Table E. ThuLS to choose a particularly preferred hu1.midity range g%01 1 h 'or lmrIekir H. Lg is selected from the oLp consisting of a value presented in the coIlumn1 headed ''in Table E below at one or more of entries I1-1I8 (where L, the mliiiIIII1 mum hu idi ty listed in 'Fable B for the particular and hi is selected from thle aroul) ot* the values presented inl thle Column11 headed adjacent tile corresponding, entry (where h thle maximum humlidity listed in Table B for the p~articuilar H).

0 TA13LEE Hum~oidit y ia n es of' Par'ameter'is 11(I,11(2), 11(3) Ent r) g I 1 1 5. 10. 15, 20. 25,30, 35. 40, 45,50, 55, 60, 75. 80. 85. 2 5 10, IS. 25, 30, 35, 40. 45, 50, 55, 60, 65, 80. 85. WO 96/02153 PCT/AU 95/00418 3 10 15. 2U. 25. 30. 35. 40. 45. 50. 55. 60, 65. 70, 85. 4 15 20, 25, 30. 35. 40. 45, 50, 55. 60. 65, 70. 75, 20 25. 30. 35, 40. 45. 50. 55. 60. 65. 70. 75. 80. 6 25 30. 35. 40. 45. 50. 55. 60. 65. 70. 75. 80, 85. 7 30 35. 40. 45. 50. 55. 60. 65. 70. 75. 80. 85, 8 35 40. 45. 50. 55. 60. 65. 70. 75. 80. 85. 9 40 45. 50. 55. O. o5. 70. 75. 80. 85, 45 50. 55. 60. 65. 70. 75. 80. 85. 11 50 55, 60. 65. 70. 75. 80. 85. 90. 95. 100, 1 10, 120, 130, 140, 150 12 55 60. 65. 70. 75, 80, 85. 13 60 65, 70, 75. 80., 85, 14 65 70. 75. 80. 85. 70 75. 80. 85, 16 75 80, 85. 17 80 85. 18 85 and P(3) have expected maximumll pressure ranges as listed in Table B.

Preferred pressures or pressure ranges within these expected maximum pressure ranges for each of these parameters are listed in Table F. Thus to choose a particularly preferred pressure range i atm j aim for a particular P, i is selected from the group consisting of a value presented in the colunn headed in Table F below at one or more of entries 1-27 (where i 2 the minimumn humidity listed in Table B for the particular and j is selected from the group of the values presented in the column headed adjacent the corresponding entry (where j tile maximum humidity listed in Table B for the particular

I

WO 96/02153 PCT/AU95!00418 3 b TABLE F: Alini rangesl.' olf' Parlalitel., 11(3) Entry i .i 1 0.1 0. 15. 0.20. 0.25. 0.30. 0.35. 0.40, 0.45. 0.50, 0.55, 0.60, 0.65. 0.70, 0.75, 0,80, 0.85. 0.875, 0.90, 0.91, 0.92, 0.93. 0.94, 0.95. 0.96, 0.97, 0.98, 0.99, 1 0.15 0. 20, 0.,5 0.30, 0.35. 0.40, 0.45. 0.50. 0.55, 0.60, 0.65. 0.70. 0.75, 0.80, 0.85, 0.875, 0.90, 0.91. 0.92. 0.93. 0.94. 0.95. 0.96, 0.97, 0.98, 0()C9, 1 3 0.20 0.25, 0.30. 0.35. 0.40. 0.45. 0.50, 0.55. 0.60, 5. 0.70. 0.75. 0.80. 0.85. 0.875. 0.90. 0.91.

0.92, 0.93. 0.94, 0.9Q5. 0.96. 0.97, 0.98. 0.99, 1 4 0.25 0.30. 0.35, 0.40, 0.45., 0.50. 0.55. 0.60, 0.65, 0.70. 0.75, 0.80. 0.85. 0.875. 0.90. 0.91, 0.92.

0.93, 0.94, 0.95, 0.96, 0.97, 0.98. 0.99, 1 0.3 0.35. 0.40. 0.45. 0.50. 0.55, 0.60. 0.65, 0.70, 0.75. 0.80. 0.85. 0.875. 0.90. 0.91. 0.92. 0.93, 0.904, 0.L)5. 0. 0 7, 0.98, 0.99, I 6 0.35 0.40, 0.45, 0.50, 0.55, 0.60, 0.65. 0.70, 0.75, 0.80, 0.85. 0.875, 0.90. 0.91, 0.92, 0.93 0.94, 0.95. 0.96, 0.97, 0.98. 0.99. 1 7 0.4 0.45. 0.50. 0.55. 0.00. 0.65. 0.70. 0.75. 0.80, 0.85. 0.875. 0.90, 0.91. 0.92, 0.93. 0.94, 0.95, 0.96. 0.97. 0.98. 0.99. 1 8 0.45 0.50. 0.55. 0.60. 0.65. 0.70, 0.75, 0.80. 0.85, 0.875. 0.90. 0.91, 0.92. 0.93. 0.94, 0.95. 0.96, 0.97, 0.98, 0.99, 1 9 0.5 0.55, 0.60. 0.65. 0.70, 0.75, 0.80, 0.85, 0.875, 0.90. 0.91. 0.92. 0.93, 0.94, 0.95, 0.96. 0.97, 0.98, 1 WO 96/02153 WO 9602153PCT/AU95/00418 0.55 0.60. 0.65, 0.70. 0.75. 0.80. 0.85. 0.875. 0.90, 0.91. 0.92. 0.9.3. 0.94, 0.L95. 0.9b. 0.97. 0.98.

0.,99.1 11 0.6 0.65, 0.70, 0.75, 0.80. 0.85, 0.875, 0.90. 0.91.

0.921 0.93, 0.94. 0.95. 0.96. 0.97. 0.98, 0.99, 1 0.65 0.70, 0.75, 0.80. 0,85, 0.875, 0.90. 0.91. 0.92, 0.9L)3. 0.94,I. 095. 0).96. 0.97, 0.98. 0.99. 1 13 0.7 0.75, 0.80, 0.85. 0.875, 0.90, 0.91. 0.92. 0.93, 0.94. 0.95, 0.96. 0.97. 0,98, 0.99. 1 14 0.75 0.80. 0.85. 0,875, 0>L)0. 0.91. 0.92. 0.93. 0.94, 0.95. 0.97. 0.98. 0.99. 1 0.8 0.85. 0.875. 0.90. 0.91. 0.92. 0.93. 0.94. 0.95, 0.9Q6. 0,98. 0.99. 1 16 0.85 0.875. 0.90. 0.91. 0.92. 0.93. 0.94. 0.95, 0.96, 0.98. 1 17 0.875 0.90, 0.91. 0.92, 0.94. 0.95. 0.96. 0.97, 0.98. 0..99, 1 18 0.9 .91. 0.92. (1.93. 0.144. (1.95. 0.96. 0.97. 0.98, 0.99.I 19 0.91 0.92, (1.93. 0.94. 0.95. 0.96. 0.97. 0.98, 0.99. 1 0. 921 0.93. 0.94. 0.95. 0.90. (1.97, 0.98, (1.99. 1 21 0.93 0.94. 0.95. 0.9o. 0.97. 0.98. 0.99. I 22 0.94 0.95, (1.96, (1.97. (1.98, (1.99. I 23 0.95 (1.96. (1.9L)7. 0.(1 (199. I 24 0.96 (1.97. 0.98) (1.99. 1 0.97 (1.98. I 26 (1.98 0.99. I 27 (1.99 1 WO 96/02153 PCT/AU95/00418 38 The present invention contemplates amongst other things methods and processes for the processing of cheese and the production ol cheese and cheese based snack foods and home microwaveable snack Iood products and cheese and cheese based stable long shelf life consumer products, and processes method and application of electromagnetic wave energy for food product processing including for example processes known as tempering. heating. glazing. puffing, cooking, browning, leavening, drying, vaporising, pasteurising and sierilising and usinlg for example microwave (MW) and radio frequency (RF) energy and infrai-red (IR) radiant energy.

The processes of present invention may be adapted to a method of production suitable for industrial commercial applicatilon Ior the production of the p)rodLucts either on a batch process basis and most preferablly on l continuous flow production basis.

The invention includes within its scope a method of plroduction in which the various processes involved in the overall production process are carried out in predetermined and programmable sequential steps either singly or in combination of more than one process proceeding concurrently and simultaneously and being at all times under the automatic control of a feedback control system which responds continuously to the condition of the product throulghout the course of' the overall production process.

The processes of the second and third embodiments may be adapted whereby the commonly known and observed prtoduct chatnges which occur during product processing including for example the phenomena of' leavening, puffing, glazing, skin effects, drying, browning, edge burning, striping and volatilising are pre-determined and quantified and controlled for each step or stage of the overall production process such as to enable a person reasonably skilled in the art to repeat the method and process for the continuous production of the product to a high standard of physical uniformity and product quality.

The processes of the first to third embodiments, may be adapted in many instances to operate at temperatures sufficiently low to eliminate or minimise the damage otherwise caused to the physical properties of the product luring processing and to reduce to a low value or to a minimum the volatilisation of aromatic substances and oils contained in the product.

The processes of the first and third embodiments may in many m/idiances be adapted to substantially reduce, or minimise or eliminate pr1lduct spoiling changes which typically I, WO 96/02153 P]CT/AJ95/O0418 occur in the product physical lormn aIl(d cllular 1t ructure and surailce conditin during processing using conventional technoloies, includiin for examnple the phenomena of product surlace changes, formation of hardened surface and skins, loss of colour, loss of flavour, glazing, browning, edge burning, chewiness, non-uniform processing, excessive drying and product exploding.

The processes of the first-and third embodiments may in nimany instances be adapted to provide relatively short product residence timcs and hence increases production throughput and energy efficiency.

The meaning of "spoil" throughout the specification and claims is to be taken as meaning that a material that is sooill is no longer suitable for its intended use because it has been spoilt. For example thIle undesirably altered appearance of processed material, tough skins on processed material, aInck of nutritional value of processed material.

chewy texture of processed material or bland taste devoid of any significant distinguishing flavour or taste of processed material may, depending on the intended use, constitute spoilt processed material.

Brief Description of Drawings Fig. I is a block dliagram depicting a preferred system of the invention; Fig. 2 is a Process Block Diaram Fig. 3 Process Step I Block Dtiarami: Fig. 4 Process Step 2 Block Diacrani: Fig. 5 Process Step 3 Block Diagram: Fig. 6 Process Step 4 Block Diagram: Fig. 7 Typical Microwave Processine Chamber Compolnents where I. Tuned Microwave processing chamber atmospheric or vacuum.

2. Microwave celerators (Magnetrons) and waveguides.

3. Dry air pressurised microwave launches with windows.

4. Controlled Temp./humidity supply air plelnulil inlets from heat pump.

Saturated vapour manifold outlets to heat pump.

6. Water load microwave emission choke sections.

WO 96i/0213 IPCT/AU95/004118 7, Variable speed r1)1-0(1 nt conveyor.

8. Processinig chamber equipment housing.

9. Retuiirn conveyor assembly; Figs Typical Microwave Processing Chamber Alternative sections; Fig. 9 Microwave Power Control System Schematic; Fig. 10 Integrated Processing System Microwave Power Control Schematic: Fig. I1(a) Microwave/Heat Pump System Schematic Diagram (Part Fig. I1(b) Microwave/Heat Pump System Schematic Diagram (Part Best Mode and Other Modes for Performing Invention Referring to Fig. I a system 100 for removing water from a material is depicted.

System 100 includes apparatus 101 which prepares a starting material to be processed into a suitable forim for processing. Tihe ype of iachine/mechanism/device/appliance employed for apparatus 101 dep(ends oin the nature of the starting material and the characteristics required of the processed plroduct from the starting material The starting material inputted into apparatus 100( Inay be solid, liquid or viscous form. for example.

Typically apparatus 100 receives pieces or links of material which have been preformed or sliced or diced or cut or pressed to a pre-deternined size and shape and/or weight relative to the end plrodluct specilIcation. Tihe preparation of the starting material into its preferred form for subseqluent processing includes for example such preparation processes as grinding. mixing. addinllg of condiments. emulsifiers. flavours. and other additives typically in standard proportions in accordance with the recipe of the particular product and blended for uniformity of thile starting material for presentation for production processing. Apparatus 101 is primarily concerned with the controlled delivery and presentation for processing of the prepared starting material at the appropriate temperature, in the appropriate orn. for example in extruded viscous form as continuous strips or drops or other shapes or as cold links of starting material all to predetermined size. shape and unit weilgh designedl to suit the subsequenllt proCessilg energy system and the characteristics o the )rodLuct material and end product specifications and quality control. For example. apparatus 101 could include: a steam kettle which heats the startinw material changing it into a viscous form and then drops predetermined amounts onto a conveyer system for subsequent processing; (ii) a WO 96/02153 PCT/AU95/00418 41 dicing machine that dices the starling niiaterial iad places the diced material in solid form onto a conveyer systemi: (iii) ;i slicing imachine that slices the :talring material and places the sliced material in solid Iorm onto a conveyer system: (iv) a de-seeding or destoning machine optionally in combination with (ii) or (iii): an extruder which deposits discreet predetermined amounts of viscout. starting material in a particular shape or into containers on a conveyer system: (vi) a hopper; or (vii) an auger/pump which deposits granular/ground/sliurry/viscou.s materials onto a conveyer system.

Starting material is fed into apparatus 101 via inpl)t con veyer system 102. the delivery capacity of which is governed by variable speed conveyer drive 103 which is connected to material presentation processor 107 via line 108. The temperature of the starting material passing into apparatus 101 i.s measured hy tcmpera ture sensing device 104, which is coupled to processor 107 via line 100. and the temperature of the material leaving apparatus 101 via output conveyer system 106 is measured by temperature sensing device 105. which is coupled to processor 107 via line 110. Heater/cooler III is coupled to processor 107 via line 112.

At least a partial barrier to moisture vapour transfer through the surface of the material is provided during processing in processing chamber 113. in which material inputted therein via conveyer system 106, is subjected to a controlled temperature and humidity environment which is maintained by heal pIlump 114 which is coupled to chamber 113 by lines 115 and 116. Heat pump 114 includes vapour exhaust I17 and is coupled to control processor 119 by line 118. Temlperaturc sensor 120, which is coupled to chamber 113, is coupled to processor 119 via line 121. Pressure sensor 122. which is coupled to chamber 113. is coupled to processor 119 via line 123. Humidity sensor 124, which is coupled to chamber 113, is coupled to processor 119 via line 125.

During processing, the environment in chamber 113 is maintained at a temperature, typically a predetermined temperature or range of temperatures. which is/are less than that which would spoil the material, and. in which the partial vapour pressure of water of said environment is below saturation whereby the material is not spoilt by burning or substantial cooking, for example. during simultaneous irradiation of the material in the environment with infra red radiation and microwave irradiation. which spoils the material. Infra red radiant heaters 126. which are coupled to chamber 113. are coupled to processor 119 via line 127. Microwave generators 128. which are coupled to chamber 113. are coupled to processor 119 via line 129. Infra red radiant heaters 126 c WO 96/02153 PCT/AU95/00418 and microwave generators 128 may be u.sed lt .siimulltaneuusly or sequentially irradiate the material in chamber 113 with infrui N red riliation and microwave irradiation, the amounlt of0 ifra red radiatioll beinlg suTficient to at least partially seal the surface of the material It provide at leasi a partial llbarrier t mollislure vapol)ur transfer through the surface of the material without spoiling the material by. lor example. burning or substantially cooking the. material, or forming a surface barrier which spoils the material, and said amount of microwave irradiation being sufficient to cause a slight positive vapour pressure within the material to prevent the material from deflating, wherein the amount of said licrowave iradiaion iria is Inot sufficient to spoil the material by, for example. substantially removingl moisture from the material, burning, substantially cooking or causing surface (damage which spoils the material. During processing in chamber 113 the following parameters of the environment therein are simultaneously maintained the temperature of the environment, and. (ii) the partial vapour pressure of water of the environment below saturation, whereby the material is not spoilt. during simultaneous irradiation of lhe material in the environment with infra red radiation and microwave irradiation. Typically. the pressure is also controlled during processing in chamber 113.

Material from chamber 113 is transported to processing chamber 130 via conveyer system 131 which is driven by variable speed drive 132 which in turn is coupled to processor 119 via line 133. During processing the material in chamber 130 is subjected to a controlled temperature, pressure and humidity environment, which are maintained by heat punmp 134 which is coupleld to chaamber 130 by lines 135 and 136. During processing moisture is removed from the material in chamber 130. Heat pump 134 includes vapour exhaust 137 and is coupld to control processor 139 by line 138.

Temperature sensor 140, which is coupled to chamber 130, is coupled to processor 139 via line 141. Pressure sensor 142. which is coupled to chamlber 130. is coupled to processor 139 via line 143. Humidity sensor 144. which is coupled to chamber 130, is coupled to processor 139 via line 145. Microwave generators 146. which are coupled to chamber 130, are coupled to iprocessor 139 via line 147. During processing microwave generators 146 irradiate the: material in chamber 130 with an amount of microwave irradiation effective to increase the moisture at the surface of the irradiated material whereby the vapour pressure at the surface is greater than the vapour pressure of the environment whereby moisture is transferred from the surface to the p-- WO 96/02153 PCT/AU95/00418 43 environment. wherein the amount of said microwave irradiation is not sufficient to spoil the material by. for example. burning, overcooking or causing surface damage.

During processing in chamber 130 the following par meters of the environment therein are simultaneously maintained: the temperature of the environment. and, (ii) the partial vapour pressure of water of the environment below saturation, whereby the material is not spoilt during irradiation of the material in the environment with microwave irradiation. During processing in chamber 130 the amount of microwave irradiation is sufficient to substantially mliaintain said vapour pressure at the surface, until a required amount of moisture has been removed from said material, without reducing the surface temperature of the nlaterial Ivore than 50% of the wet bulb depression of the environment.

Processed material from chamber 130 is transported to sterilising/finishing chamber 148 via conveyer system 149 which is driven by variable speed drive 150 which in turn is coupled to processor 139 via line 151. Temperature sensor 152, which is coupled to chamber 148, is coupled to processor 153 via line 154. Cooler 155 which is coupled to chamber 148, is coupled to processor 153 via line 156. Microwave generators 157, which are coupled to chamber 148, are coupled to processor 153 via line 158. During processing microwave generators 157 irradiate the material in chamber 148 with an amount of microwave irradiation effective to sterilise e e processed material from chamber 130. The sterilised product is transported 'from chamber 148 to storage container 159 via conveyer system 160 which is driven by variable speed conveyer drive 161 which, in turn, is coupled to processor 153 via line 162.

Processors 107, 119, 139 and 153 are coupled to integrated systems control processor 163, via lines 164, 165. 166 and 167 respectively.

In use, starting material is transported at an appropriate rate into apparatus 101 via conveyer system 102 which prepares the starting material into a suitable form for processing. The appropriate rate of conveyer system 102 which is determined by the downstream processing rate in chambers 113, 130 and 148 is governed by variable speed conveyer drive 103 the speed of which i. controlled by a signal from processor 107 via line 109. processor 107 being controlled by processor 163 via line 164. The temperature of the starting material passing into apparatus 101 and leaving apparatus 101 is measured by temperature .sensing devices 104 and 105. which send signals to I- I WO 96/02153 WO 96/2153 PCT/AU95/00418 44 processor 107 via lines 109 aind 110 resp~ectively, wiich III turnI Sends signals to heater/cooler I I I via line 11-2 to adJust thle tem plenutII re of tile mlaterial in al)lparat us 101 whereby the material leaving appatratuIs 101 is at at predetermined temperature.

At least a partial barrier to moisture vap)our tranSfer through41 the surface of' the material is provided during processing in 1)l1'ocessino chamiber 113. Material at a predetermined temperature from apparatuIs 101 is inpuitted into chamber 1 13 by conveyer system 106.

The control led temperature and humidity envi ron ment inI chamber 1 0h is maintai ned, during processing, by heat pompl~l 114 which is controlledl by processor 119, via line 118, (which inl turn is cotntrol led by proLce.ssorI- 103 via li ne 1 65). which receives signals from teniperature sensor 120. via I inc 12 I1. pre~SSUre SenlSOr 122. via line 123, umidity sensor 124, via line 125. at aI temperature. typically at p.redetermined temperature or range of temperatures. wliiCh isaele ssta t hat Wh Cli wool ciSpoil the material, and, in which the partial vapour pressumre of' water ot saiid envi ronment is bielow saturation whereby tile material is not spoilIt durIing0 i rrad i at Ion o01' the mllater-ial inl tilie en vi ron ment with niicrowave irradiation. During liroceSSiigL infra red radiant heaters 126 amid microwave oenerators 128 are controlled by) lprocessor 119 via lines 127 and 129 (Which ill turn is controlled byv processor 163 vli line 165) SiltllaneCously or sequentially irradiate the material in chamber 113 with infrat red radiation and microwave i rradiat ion, the amomit (11' infrIra red Iml iaiolid ugll 51 fiClint to at least partially seal thle Surface of the miaterial to provide at least at partial barrier to lIIiioSttre vapour tranisfer throughl the surhICe Of tilie mat.1erial1 so Ia1ce eun&It iou01 thle miaterial for later processint, such as ptiffing,. Ior exaimlile) without spoi Ii g the material, such as, for example. liv horning oi- cookinu the mnaterial, or datniaii hg thle Surface of the miaterial aid said allioulit oh' microwave irradiation bici h suL ff1icielit to cause a sI ighit positive vapour pressurIe Wi thi ile material to lreitthe material from cllating, wherein the aniount o1' said ini icrwve i rracilitionl is not SuffIicient to Sl)ii the material, Such as, for example, by burning, ort subistantially cooking tile mlaterial or damaging tie surface of tie material. Durino processimig inl chamber 113 the following p~aranieters of the enviromnmienit thiereini are si noltamiCOuIsh y Il iiied i) thle temperature of thle envi roilmnt. and, 0ii) the partial valiouur pressu re ot' water of the emivironmient below saturation. whereby the miaterial is not spoilIt during processing. Typically, the pressure is also control led during processing il chambher I113 typilcallhy sI ighitly less than atmospheric to avoid vapour eissionis from chiamiber 110.

WO 96/02153 PCT/AU95/00418 After processing in chambnher 11.3 material Iherel'froi i s transported i at controlled rate to processing chamber 13() via conveyer systell 131 which is driven by variable speed drive 132 which in turn is controlled by processor 139 via line 133 (which in turn is controlled by processor 163 via line 166). Thte wkntrolled temperature, pressure and humidity environment inll chamilber 130 is maintained. during processing. by heat pump 134 which in turn is controlled by processor 139 via line 138 (which in turn is controlled by processor 163 via line 166), which receives signals from temperature sensor 140, via line 141, pressure sensor 142. via line 143. humidity sensor 144, via line 145. During processing moisture is removed from the material in chamber 130.

Microwave generators 146. which are \whicii are controlled by processor 139 via line 147 (which in turn is controlled by processor 103 \via line 16). irradiate the material in chamber 130 with an amount otl minicrowave irradiaiou effective to increase the moisture at the surface of the irradiated matealllll \Vllhereby the vapour pressure at the surface is greater than the vapour pressure of the environment whereby moisture is transferred from the surface to Cthe environment wherein the .amount of said microwave irradiation is not sufficient to spoil the material by for example. burning, overcooking or causing surface damage, During processing in chamber 130 the following parameters of the environment therein are simultaneously maintained: the temperature of the environment, and, (ii) thile partial vapour pi-ressure of water of thile environment below saturation whereby thile material is not spoilt during irradiaion of the material in the environment with microwave irradiation. Durin2 processing in chlanber 130 the amount of microwave irradiation is sufficient to substantially maintain said vapour pressure at the surface, until a required ,amount of moisture has been removed from said material, without reducing lithe surlace teim perat ure of thile material more than of the wet bulb depression of the environment.

Processed material from chahmber 1.30 is transported to steriiisin2/finishing chamber 148 via conveyer system 149 which is drivenll by variabhle speed drive 5IO which in turn is controlled by processor 139 via line 151 (which in turn is controlled by processor 163 via line 167). The temperature in chamber 148 which is sensed by temperature sensor 152 and which sends a signal to processor 153 via line 154. is typically determined by cooler 155 which is controlled by processor 153 via line 156 and microwave generators 157. which are controlled by processor 153 via line 158 (which inll turn is controlled by processor 163 via line 167). Dluring processing microwave

L

WO 96/02153 PCT/AlJ95/00418 46 generators 157 irradiate the materina inll chamber 148 with an amount of microwave irradiation effective to sterilis the processed material 'roim chamber 130. The sterilised product which may be packaged inll chamber 148 is transported from chamber 148 to storage container 159 via conveyer system 160 which is driven by variable speed conveyer drive 161 which, in turn. is coupled to processor 153 via line 162 (which in turn is controlled by processor 163 via line 167).

As will be apparent from thile above description thile overriding control, coordination and integration of processors 107. 119. 139 and 153 are determined by integrated systenms control processor 163, via lines 164. 165. 166 and 167 respectively.

The processing systemn typically comprises four distinct steps as described above with reference to Fig, I and as is illustrated inll Fig. 2. These steps include: Step I. (Materl Ire-Processig) This step is as described above, and as sllhown in igs. 2 and 3, receives the starting material in natural or pre-processed form over a wide range of material temperattres and converts thile material into a physical form suitable for processing and delivery of the m'terial at a pre-determined temperatture to the initial processing Step 2.

The Step I process typically utilises standard industry product preparing machinery and standard industry heating a1d cooling Ns\stenm and cont01 equipment for this process. The end physical form of the product and method of delivery, and applications to the conveyor systems in stel) 2 is pecuCLliar to thile invention process.

The optimum physical form and temperature and method of preparation of the start material is determlined for each product as described above and having regard to whether thile raw miaterial is from bulk storae inll viscous or solid form or in a hot viscous form dlirect froml an upstrcll n process or in fresh or processed form.

The processing capacity and delivery rate of the product preparation and preparation apparatus is controlled by [e downstream plIrocessing capacity of Steps 2-4.

By way of example. the Step I apparatus lior the p)reparation and material sourced from alln Uipstream prodtuction process wouldl need only to comprise a positive displacement pump and applicator system with pipework heating and cooling means

I

WO96/02153 PCT/AU95/00418 47 to deliver the sinrt material hrough an extruder to the precise dimensions and temperature and pacing for entry to and processing in Step 2.

In other examnples. the apparatus of Step I may conprise standard industry slicing, dicing. peeling, cutting, skinning. stoning, honing. filleting type machinery fitted with specifically designed deliverl and presentation apparatus and/or microwaveable processing containers Air the transport of the product concerned.

By way of further examples. cheese products may be in solid folrm of natural and processed cheese- or cheese-based produLcs of various shapes and sizes and presented to Step 2 at various temlperatures.

The requirements speciied inll Step I also suit thile processing of many other materials. for exalmple those listed above. This list of examples shows that the potential range of products may be in liquid or viscous or solid form and in whole or reduced form, natural or pre-processed and across a wide range of raw product temperatures.

Typically, an "optimum" processing input tempetature and physical form of the product is first determined to establish Step 2. "process start conlition". These product requirements could normally be met by using standard industrial process machinery and control systems.

Step 2. (Initial Processing) The initial processing step. which is in accordance with the first embodiment and related clauses andl is described above, and shown in Figs. 2 and 4. is a process carried out under a controlled pJrocessing environment condition at atmospheric or sub-atmospheric pressure depending on the product.

The step incorporates infra-red radiation and optionally mnicrowave processes and a vacuum pump vapour extraction/condensing heat pump environmental control system to maintain the processing enironment pressure. temperature and saturation condition.

There is also provided an infr-a-red radiant healing system integrated with the heat pump drying and microwave systems whereby the surlface condition of the product may he pre-conditioned if requitred to increase tie resistance of the surface of the prodluc to the passage of water vapour and volatile compound vapours emanating fronm within the product.

I; WO 96/02153 PCT/AU95/00418 48 It should be appreciated that the product surface conditioning process which. by way of example. may include the brualion of a surface skin or glazing or melting or hardening or other formn of reduction in the surface porosity of the product and which does not spoil thile prioduct, is to create a barrier of resistance to the passage of vapours from within the product resulting in turn to an increase in the internal vapour pressures as heat is applied to thile product and especially invasive heating such as microwave heating and causes the phenomenon known as puffing" as the vapti rs undecr pressure break throuMh thile product surface barrier.

The processing ambient environilent for 1this processing stage is typically maintained at a pre-determilned adjustable pressure selected to best suit the processing needs of the product concented. By way of example the ambient environment pressure mayi be atmospherc but preferably sub-atimospheric and selected to take advantage of thile known reduction in vaporisation temperatures with reduction in ambient pressures.

In processing applications in which the processing environment is required to be maintained at sub-atmospheric (vacuum) conditions for example greater than 1000Pa negative, the product entry and leaving conveying apparatus incorporates a conveyor transfer mechlanism whereby the continuous product entry and exit from Step 2 is accomplished without significantly affecting the processing environment pressure in Step 2 processing chamber.

0 By way of example. for liquid, viscous and grainular or diced material, this transfer may be accompllished by the use of interlocked rotary valves in the inlet and discharge transport systems in Step 2 For other materials transported on conveyor belt or on pallets or in containers this trarsfer may be accomplished by a transparent transfer mechanism via can "air lock" neutral pressure zone having interlocked air sealed access doors or slides connecting between thile Step 2 transport system and thile respective feed and discharge conveyors.

By way of further example where the process in Step 2 is to be carried out at atmospheric pressure or sub-atmospheric pressures not exceeding 1000 Pa negative (to prevent vapour emission to tilhe surrounding atmospheric) the product WO 96/02153 PCT/AU9S/00418 49 conveyor transfer differential pressure mechanisms may be omitted and a Conltinliois single conI\CVo, Systeil usd (i l ajppropriare) fromn the delivery from Step I to the product entry at the finial packaingll stage Step 4.

L* 2 control system provides or two principal modes of operation.

miclrowave land IR Ipower control.

product temperature control.

Undler power control mode the power Clevels of the microwave magnetrons and I.R. heaters is set to a pre-determined set-point in the range 10-100% for microwave eneroy and 0- 100% in 10% steps tfor the I.R. heaers.

The control systemlls minrains the actual power inptl)ts relative to the set points.

Under this mode the product surface temperature is not controlled but is displayedl. The environmenil ta I cl to. isystcms operates independent of the power input levels and maiain s predetermined pre-sel \alues of enltry air temperature and saturation and pressure conditions.

Under product temperature control mode the leaving product surface temperature is set at a temperature relevant to the Iprocessing environment dry bulb and wet bulb temperature and pressure and maintained by controlling the miicrowave power input. Undler this mode the heat pump mai nains the pre-set operating conditions for the processing e nvi ron ment. The mllicrowave power input is continuously varied to mnaintan the set product temperature. This control mode provides a means whereby the dry bulb and wet bulb temrperatures of the recirculating ambient air/vapour mlixiure in the product processing chamber which incorporates integratedl mnicrowave assisted vapour extraction/condensing, closed cycle, heat pumnp heatiig and drying system operating in a controlled, adjustable temperature and pressure environment witl product temperature control is controllable relative to tile surface temperature of tle product being processed such that the drying process is engineered to operate as an adiabatic or isothermal process or at any pre-ldeteriniled comnbined process between these two specific conditions. and is particularly relevant to the processing of materials which are sensitive to hIlighler operating temperatures and potential vaporisation or aromatic compounds. Materials in this cateory include for example. some cheeses, meats, fish. fruits. herbs and spices.

I I WO 96/02153 WO 9602153PCTIAU95OO418 Step, 3. (Filial l),ocessi,I This process step. which is in accordnce with I 1w second embodiment and related clauISes and is describedl above, and shown in Figs. 2 and 5, is a final cookiing/dIryingf/puff-ingt/km),iuii,/priocessinii. stage isapptlllicable to meet the end product specifications and incorporating con1tinuLouS] y \'ariahle prodcIIt feed hack control led electromnaunetic wave heating inI, temperature and pressure control led (atmospheric or sub-at miospheric) environment comp~lete with vapour extraction/condensing system and emission control is thie mat n p~rodutction process by microwave heating. cooking. puttfing), drying" !IS reqJuired and (dli very of the finishedl prodLoct rea'dy 1'0r Steri I iltloll, pa1-steu ris-ittion. de-natutring andc cooling ready for packaging ill Step 4.

*Alternatively, Step 4 may for example inluLde ])rOdUCt de-natuiring", pasteulrisation or sterilisation cool in, and pitckaging as A SeparIate hut integrated p~rocess. This will depend onl thle nature 01 theC product being, processed aind whether these produIct processes are required, for example. as products for human conIsumIptionl or industrial proucLIts.

Step 3 may for example also include prov'ision for illfra-red radiation. browning of the finished lprodLuctS suchI as t"or lbiscui tS and Snack foods.

In general respects the apparatus Cor Step 3 process will he similar to Step 2 apparatus and inludII~e a1 WacLluII U)I11 puInpaour ext raction/coc~nlensiltg heat pumIIp system and prod uct conv\ey'or trans 'er mfechianlism it' requLired.

It should be appreciated that the influence ol' the processing ambient environment for example with respect to operatinig pressure and temperature and ambient saturation condition in the final production process is affected by tile microwave heating characteristics such as micromwve intensity and power/ti me control relative to the lrodLulCt mo1iSturte Contenlt. S(1 rtice telipIerature and end product speci tication.

*A Means maliy be iInel LIdld Whereby) theC pIlWC.SIIIL) ambient environmIfent for this final prod uc~tionl stage is mai nta11iied at a pre-determ ined ldi ulStable pressure to best stuit the final processing reqJUiremlents havinu regard to the entering product temnperature and moisture content arid final product specification with respect to such aspects for example as lillishedl prodlct mnoisture conitent. desired surface WO 96/02153 PCT/AU95/00418 51 texture condition and colour. 1degree of pu l1nin. iclemperat rC sensitivities of tilhe product being processed ant sterilisation/ti me characteristics. By way of1 example the ainbient environimnil pressur br m c 1 atlmospheric but preferably subatmospheric and more preferabl Iy a specitlley dletermined sub-atmospheric pressures to best suit the particular producl processing characteristics and end product specificatio., By way of further example typical preferred ambient environment sub-at mlospheric (partial vacIIuI11) processing pressures for the mllanu Ifacture of non-puffing products irefe rred to in this specification is in the range of 0.90 to 0.98 atm and for puffing products 0.30 to 0.90 atm and for Ioaming products 0. 10 to U.30 aili. uthr pressurc conditions are equally provided to suit specific proIduct needs.

Thile control System r Stel p 3 typically' prov lcs lir fourll operatinu modes. In its preferred form the control sub-system for thle microwave heating and processing sub-systems there is provided tr example: an operators control panel incorporating a series of keys and displays to indicate and control thile sub-system status, operating mode. timing, power set valves vs actual, temperature set point values vs actual and parameters which dlefine the behaviour of the PID controller.

Mode key or selecting any one of f-our operating modes or combination of niodes throuighout the complete productioil process and including thile preferred miodes of: power control temperature control power profile temperature proile, A SET KEY function inll whiclh tile prefe rrd cllbodimentll is that the set key is used to make or change the settings for power set point value. temperature set point value, proportional. initegratriv devative and Tf parameters of the temperature controller and the settings made can be changed at any time during the process withouit any shit-cl-down of tilhe colmplete process or any sub-system process.

Wo 96/02153 WO 9602153PCU/AU95/0041 8 52 Ini POWER CONTROL mnode user call set the power set point v'altie in the range from 0 to 100%,'1~oo~oaIitga Ce cntroller incorporated inl so ftware maintains the actual power valute relativ\e set point Valltie. The actual temperature of the heated product is displayed in this mode htit is ntot conl!rolled.

Ini TEM P CONTROL mode uiser can set thle temiperatureC Set point value inl the rang~e from 0 to, 200CC and rprtoa- teriy-en\a v controller maintains thle actual temperifturle arotin11d Set point value. Power set point and actual valute and tern peCrattireC set pMi it anld aHct11- til 'l te.s is dli splayed in thiis Mode.

Ini POWER PROFILE Mode tiser canl set tip1. to 99 timle periods (the duration of each time p~eriod Can11 tbe up1 to 999S9), Foi ech01 Se~ient tiser Canl Set start power set poiiit and final po0wer set point.

Ini TEM PERATU RF PROFI Lfl modte us~er can set ill) to 99 time periods (thle doration of each timle period can hC tip to 999s). For each segment tuser canl set temrperature set point and final temperature11 set point.

The operating modes provide for a wvide range of' set point conditions to suit the wide range of' potenial aplications of' the p~rocess.

0 In lower temperattire applications suIch ats for the processing of' cheeses, nmeats and fruits, thle temp lerattire control" and teinperat tuie protilec" thle settings and operation would typically relate to thle processing amibient conditions as noted for Step 2 'product temnperatture control".

a A PAUSE KEY operational control onl each selected magnetron or banks of magnetrons may be provided in which the operation of the PA USE KEY will suspend thle timinrg. function and IltOWel' supplY to tie mnagnetron(s) is switched off and the filaments remain onl f 6r anl adIJustabl lre-dletermlined period of typically I Os onl Comnplet ion of MIM 111Ci leXM\%ci. Sti I) Is a ti ton1itcl ly Switched off and operator alerted.

Step 4. (Eiad Product Packaglinug This step is as described above, and as Shown in Figs. 2 and 6, typically involves product tliicrowave sterilisation and packaging and cooling stage and as noted in the specification thle process of steri lisation and browning cain be incorporated in Step 3.

The end produtct wotuld theni pass thirotighl a cooling sectioii to the prodtict packaging machine. Induistry trend is for tile sterilisationl Of thle prOdtLict to lie incorporatedl in tile WO 90/02153 WO 96/0153 1'TIA U95/004 I 8 packaging stage, MIicrowave steri listi on is a proven process and appropriate packaging and control systemns 0rV col irilIWIW hc. TherL Ilay be provmcted as anl integral part of" the f'inal lproccssi no stage as described in Step 3 thle optional additional process of' product surfaice brownino± whiuL is atccomiplishied f'or example by control led in frared radiation of' thle product as a Ii na I pr-oCess. As an1 integral part o01 tile final processing stage as dlescribedl in Step 3 tihe optional additional process Of* prodcIIt sterilisation by microwave heating prior to coolingL andL/or )ackaoi ng of' thle finishied produict mlay be in acted. In its preferred formi there is provided in step) 3 anl integrated cooking. dIry i ng, p ffin mifoamlingt and if' r-eqa i rd prodIIC ac trO\Il i nl and sten Iisat ion stages operating in a cot arotle~d. adi Stat)C Ic enIIpLrtRI arnavd pr1e.ssLIre en Vil ron ment Conveyer System There is provided in thle initial and 'i nat p'ocessi ng stages of' thle Iethoct of' mnanufactUre a product processing, conveying, systeni or conveying arrangemlents incorporatinu as appi cabte tile *Ol lowin.au r: transparency to microwave radiation.

Incorp~orating by way ot* integral forming of' thle conveying platform speciftic shapes, indentations Or p -ceSSill ncontainers an1d attchnmen Es construicted of microwave tranlsparent miaterials in part or in whole.

Means for the automatic weparatioln of' theC produLct fromi the conveying platform or contai ner without recourse to the application ot' release agents.

Means for tile separation and dra(niing ot and reclaimfing ot' any oilIs formled in tile poesill L.ich a illanner ats to elimilinate tile recyngm of any oils which might give rise to burning and contaminationl of thie subsequent p~rodlucts being processed.

Variable speed coinveyor cointrol interlocked with the integrated process control systemn to provide a wide range Ot tprOCeSS reSiStIjlce tiillCS.

Microwave Control Feedback Mechanisms General Processing step 3 and typically processimg step~s 2, and 4 of ttle inlvention each incorporate a microwave jrocessing systei.

WO 96101153 WCTIAUI95I/00418 54 Thile microwave power cont rol rqiuremenis are different fOr each Step. The general fuinctional requirements of the control systems re described above I'for each of the Steps.

Microwave Energy Input Microwave energy is supplied to the separate processing chambers in process Steps 2, 3 and 4 by one or mIore microwave generators (nimgnetronls) for each Step as determined by the product processing reqluliremients. 'The i-agnetrons may he connected to the processing chambers directly via wav'eiuide launching sections or via a system of waveguides from remote rack mounted mane IllCtr'aS. There may he provided an electromagnetic wave heat generator and transmissionll system of wave±ulides and the like and generator cooling system indorriOted in Iand intcUgrated with the production machine in smiall capacity production machines or in preferred form as free standing microwave heating energy Imodules witlh energy transmission by wave guide connection to the processing chambers of larger cIapacity production machines. There may be an arrangement whereby the electro-magnetic wave heating energy may be transported by wave guides or the like to variousi lo!.l ions within the production machine and at energy input levels which may be varied utomatically to satisfy process heating and product surface temperatureIle conditions relative to Irel i red rates of cooking and dehydration throgihout thile pOdluction cycle.

In the preferred form the magnetrons will be water cooled and 1mounted in close proximity to the processino chamber and connected thertcio by puIIrpose-made lallunchin g pieces fitted with tuning stubs. matching flanges with RFI gaskets and PTFE or other microwave transparent windlow to separate tlie wavegllide lilaunchinrg piece atmlosphere firom the product processing compartment at mosphere.

The launching piece or waveguiide connection piece between the magnetron and the processing conmpartment is preferably fitted \\'iih an are detector and is slightly pressurised to above atmnospheric pressure with dry air so as to increase the breakdown voltage within the waveguide iundelr humiinid environments (see Fig. 7).

The geometry of each processing compartment and the disposition of the microwave connections in its preferred 1form is tuned and matched for h tigh efficiency microwave heating performance with the minimum of microwave radiation coupling between WO 96/02153 WO 9602153PCT/AU9500418 adjacent niagnietron n Pu isN 1( ensoeStIl ILab' 0l)e Riton 111d Sm1o011 Iia1ri ab e poWer control (see Fig. 8).

The geometry of the microwave processing comnpart ments inl its preferred form has anl equal sided pentagonal cross section to more eilecti\'ely and evenly distribute the microwave energy intensity with reSpect to tibe p)rHd act Om er geometrical formis of tuned microwave proceossint, chamlber designs are also suitable for tbe invention process.

The processing chambers f'or Steps 2 and 3 are designed ito operate either at atmospheric pressure or preterablN stb -atmospheric (partial vacuIn1) Conditlions, To further provide f*or stable aYICl crwae1.snoerationl and to enIsure the long life of mag~netrons, inl its preferred 1torirt thle ma1;11uet rons are fitted with isolators to absorb reflected energy and (lissipate1 this enlelg thr1oLugh a dummy1111 Water load.

Effective shielding against the eisiOnl Of ectomaei waves from [lhe microwave radiation processes carried ouit Within thec machine is generally provided stIChI shielding complying with internationally recounisecl health andl safety standards.

In all of the lprodUll process chamber1CIS anid con1l\ eying1 systems in all of their formis and con 1figuirations a level of allr tiolitness its typically required to mini misc air infiltration to the machine and to satisfy thle requirciments fbr suIb-atl mospheric pressure operation.

Microwave Power Control General Background i nlbrnation onl microwave power supply and other variables and operating modes and typical f eedback arrangements IfOr providing constant input power stabilisation is described below.

Magnetron Power Supply Background *The eff-iciency of' the mnicrowave niagnetrom is typically constant for a fixed load Linder all operating conditlions. To stabilIise the magnetron power it is only necessary to stabi lise the magnetron input power.

*The otput power of the magnietron (thle mnicrowave clenerator) can be influenced by: miains voltage variations (the major intluacng, factor).

WO 96102153 PCT/AU95/00418 56 an increase in temperature ot the ferricv mawlets. This weakening the magnetic field and lowers the nAde vOlitac.

changes in the RF load which al iters thlie anode volta-e at a given current. This influence is of lesser si gnificance whenII using± a tuned microwave system in continuing process applications having substantially fixedly load characteristics for example in the independent processing Steps 2. 3 and 4 of the invention.

The proposed control system in the invention caters for these load changes.

Mains Voltage Variations Power supply authorities do not guarantee the mains voltage will not be subject to voltage variations. power surges ori voltages spikes which are caused by varying loads and demands. faults and switching tranllsient.s inll the distribution system.

Typically the mains supply is delivered at 220() to 24() vols AC and at a frequency of 50 Hz or 60Hz depencling (oin the country and d istribution system ill place. Three phase power' supply may typically vary heiween 380 and 415 volts AC at 50 or 60Hz. again depending on the characteristics of the main supply system.

Typically, the mains voltage may 11ll 1 up to 5% even inll well regulated distribution systems. Unless compensated by the control system these mains voltage variations will cause wide fluct ouations in thile output power of the magnetrons, For example, thile output power of a connuonus wave milagnetron rated at 5KW at normal mains voltage can fall to 0.5 KW\ with a drolp in mains voltage of Typical comnmercially availahblc miagnet ron power control systems stabilise the output power against variations illn mains sulpplly voltage by varying thile magnetron electromagnet coil current and varying the filament voltage to maintain an acceptable cathode temperature. Providin tilhe internal impedance of the HV power supply is low, only small changes inll the electroimnnet coil current are needed to produce large changes in magnetnron outf)ut fowcr.

Figure 9 is a block diagram showi g a typical magnetronll Power Control system using the principle of constant input power stabilisation which by way of example could be incorporated in the basic microwave power control in the invention.

Magnetron Variable Power Control

I

WO 96/02153 PCT/AU95/00418 57 As already indicated the produulic n process typically inlcorporates four distinct processing steps as depicted inll Iig. 2.

Process step 3 and optionally process steps 2. and 4 incorporate microwave energy processing which is required to be independently controlled to respond to processing criteria relating to the particula r process step.

The optim'um microwive power input to the process will vary for diiterent products being processed and is inlluenced by the interaction of the lollowing processing parameters which will be sensed and electronicl ly processed as signals to provide for stable system Operation and conltilnuously variable miicrowave power control in coijunction willi the power stahilisation control noted on Fig. 9.

SThe processing inpltts inclutlde: I the surface tenlperatu re 01' the Iproduct beillng processed at entry and exit from each process Steps 2 to 4.

the dry bulb and wet bull temperature of the processillng eivironment inll Steps 2 3.

the respective processing chamber pressure inll Steps 2 3.

conveyor speed ill eaclh ste..

The control system described inll the invention provides for four basic operating modes which are applicable to Step 3. Two operating modes apply in Step 2 and Step 4.

The four mniodes are: (I)Magnetron power control.

(2)Produlct temperature c0ntrol.

(3)Microwave power profile.

(4)Product surface temperat reC proIC.

The most appropriate operating mode or combination of modes throughout the manitfacturing process will be dejpendent on the product characteristics and the end-product specification.

The product characteristics and end plroduct speciication will fundamentally determine the optimum processing environment e.g. whether at atmospheric g I WO 96/02153 WO 9602153PCT/AU95/00418 pressure or slight or substinti al I u-atIIOSphler-IC \',IciiLam) Jpresmires. Thle processing ambient pressure Will he Jpre-determilled I'r each lproCiLict anld pre-set at start 11 p0ol thle pairtiCa Il', prIOdLC ciNl-Od uctO1 on L 11. The olperatI n amIlb ien t temp~erature and processi ng at mOSphlere dr) bulb telln perit Lire and atmosphere saturatiOnl conditiOnlS Wi I Ibe- 11 1nti n1Med1C byN the) vacuum pump 1 1 ll vapour extract ion/conden si ng. heat pumpl system:,. indicated it, Figs. 2 and 3. Thllis control system maty use coin niercidly lV valiable cor11n0 rol cl)Ipent and temperature.

pressure and hum~lidity1 senlsors Mnd Ceedback controls. The environment control systemn could be exl)ected to operate reliably and in at stable thashion when the operating parameters are pre-set for thle partI-iCular prIO~eS.ss The con1tinul)Sy vaible~I J)~e ki' control of' th1C microwave magnretron energy Input to the process provides I rc-ad\ men \11I) 1ere C the tmpeIrature 01' the lrodLuct being p~rocessed can be accurattely controlled to at sl)ecitlc set point relationship to the dIry bulb temlleriltare Of 11te prI-0eS.Sij1 ugevi ron nentI atmnosphere. As noted previouIsly this Control 'Cfeature eniables isothermal and near isothermal moisture transfer to take p~lace between the produvt and the at mosphere without sensible heat exchange. This control Featuire of' the invent ion enables drying of* heat sensitive produIcts to be achieved in low temperature environment with appropriate vapour pressure diff-erences.

As the microwave processing requirements in each process Step will vary considerably across the range olf potential lprodLict al)l liCitionls the iniicr)\ave p~owAer control systemn in the invention p~rovides for thle continuiously v \ariable control of powver input of each magnietron. This enables the mic'omwe p)ower levels of' each magnietron and bank of' mnagnetrons serving each processing chamber to be either pre-set to provide a specific power output1 or alternatively at 1roille of' power outputs in each compartmlent to suit the processing needs of' that compartment. These p)re-set conditions may be set for continuIous p~erformanlce at thle selected p)ower Ouru~s I )O~er profile or mlay be conti iiuouIsly Varied by p~rouctLC tefflpeiatt are feedback imic roprocessor control.

In its preferred form the Control syISemI Will oplerate onl at cointiouIs flow lprodtction basis btit may also apply to batch typ~e processors with the introduction oft process-time (produIct residence time) control appliedl to the icirowve fixed power or power profile settings.

WO 96/02153 PCT/AU95/00418 9.

The nianufacture of microwi miuIagnetruns speCi fV part C)u; lar t m1e delays to be incorporated in various circuits oI the power control systeim tor saiet reasons during start-up and slhut-down of the system. These sa tety provisions form anll integral part of the power control system.

Magnetron Power Control System The magnetron power cintrol system ill the preerred form ol' the invention is depicted in Fig. 10 and provides the Ii low.\ing basic control features: good dynamic regulation.

accurate and stable pre-settimn of the RF Out put power in the range 10-100% of each magnetron for a wide range ol anode voltge anlid anode current conditions.

power related signal lor ilament voltage control.

Inagnetron outpuLIt powef disl)laV in watts.

incorporation ol* protectio cirints.

provision for incorporating integrated system feedback signal control of magnetron power settings.

Power Stabilisation As previously noted tilhe anode voltage of the inag netron depends on the AC mains voltage variations and the internal resistance of the p e\\'er SLIpply, the latter being tenmperature dependent. The anode current depends on the anode voltage. the electromagnet current (for some mnagnetron designs) and the minagnetron system load.

By way of example. the following description refers to the control supply for a typical continuous wave water cooled muagnetron. Other mniaginetron control systems will vary in control Cldetail but not in prillnciple.

Microwave Power Output Measurement The anode voltage signal is typically -7.2V and the anode current signial is 950mA.

Both signals are mnultiplied electronllicall such that the ou11pt X ia is proportional to the real RF power that is Xa k(-V a)hi where the proportionality constant k is used to limit Xa to 10V (where Va is the anode voltage and lia is the ainode current). A voltmeter connected to the output of the mul tiplir can be used to indicate the microwave power.

L I WO96/01is PCT/AU95/00418 b() Setting the Power An adjustable DC reference voltage of I to I0V rom a potential divider is used to set the input power level. The mdI inimum vollage is set by the permanent voltage divider comprising specific resistor ratings. During standby the input voltage to an impedance converter is kept at OV by a closing switch. When this switch is operated the input voltage rises to.the present value (time constant 1 0. 1 sec). An invertor is provided with a reference volhwae of IV to IV.

Control Amplifier A control amplifier with P. I characteristics keeps the microwave power constant at the set value even when large main s voltage Ifluct untions occur t at low alnode CLIrrents. The input signal is the difference between thle signal representig the desired power and that representing the instanianeous power. The signal output of the control amplifier is limited to I0V by zener anodes. The useu of' 1. I amplifier provides good dynamic regulation. If necessary this regulation can be imnproved by converting the amplifier to a P.1 D amplifier.

Power Amplifier For Electromagnet Supply The output of the control amplifier is the input lfor an iniegrated power amlplifier which has short circuit protection and a current limter. Tlhis aImplifier is stable in operation even at low input vol taes and prov\ides n .Nmooth transiion s. the enerisation of the electromagnet reverses. The electromancet can be turned off by a signal from the controller. Provision is tmade to prevent microwave energy being generated when anode voltage falls below the manuiftacturers recommendations.

Anode Current Control An impedance converter and coimparator monitor the peak anode current. The output of the comparator is used to shut clown the power supply if necessary.

Filament Voltage Control The control system for filament voltae control utilises a standard available control package which is imatched to the I'ilament operating requirements of the particular magnetron characteristics, When the anode current increases, the filament voltage is reduced to prevent overheating the cathode. Di1i n g war n-p with no anode voltage applied. the filament WO 96/02153 W096/02153PC7YAU9I1O4 18 61 voltage is 5 V at nominal mains voluLtgc I )u ng. operation. thle filament Voltage is reduIced to 4 V and thereafter contlrol ld heMVTw M' and1( 4 \1 (tleendl' gOn thle anodce current.

In a typical l'i lamen I voltage con trol Icir-cuit. I Signal1 proportional to thle map netron current is amnpli fied and p~hotoCotipled to thle inputLl of a TC'(A2-80A uised to control a triac which reguLlates the filamntt v'oltae accordincg to the cleratin, cuirve of the magnetron.

During warm-up, before thle anode voltage is appl ied the control circiti is by-p~assed and the triac is Shunted byI 2 Switch.

The maxilmum and mninimum111 filament voltagev are sct Wtthi the anlode voltaoe off, and a switch opened to activate the triac.

To set the maximumi fi lament volta-e, thle iniput sig nal is set to zero atnd aditustecl for a filament voltage of 4 .OV measmired -at Hte imignetronl.

To set the minimutm ftilament voltage1 at cu rent of dJS0n, A is S0t and alj USted for a filament voltage of 0.5 V.

Start-Up and Shut-Down Procedures These proceduires are specified by thle magnetronl 1mnufactut-ers and by way ot example typically incluide the following sedluences: Monitoring of the matmetron cooling circuit for satisfactory operation for abouit 3 sec befote operating the fi latment heatig.

2.Start cathode heatinkg with a fix~ed filament voltage of 5 V and allow a preheat Of ab)ot 15 sec before operating thie magnetron.

3. Before switchito onl the anode voltage, the electtromaonet cuirretit shouild be maxi mum (positive) to ptevetnt the magnetron oscilIlati nt when the anode voltage is outside thle operatling rnge of thle power stabilIisat ion circuit (i.e.

when the anode \'oltaoe is less than abouit 51NV).

4. Power stabilIisation and ti lament vol tagv conittol active. The r. f. otttpLt power increases to thle set value and is stabi lised at that vaile.

Integrated Systemn Control This control system (see Figs 4 and 5) p~rov'ides tor thle integrated control of the sttbsystemns in pro0cess Steps I to 4 it)o pettte init aC011ntIOItoS Seqluential produIctionl mode WO 96/02153 WO 9602153PCTAU95OO4 18 62 for the m'lan fi'-ct are Of prod acts Wc 'rred to in tile invent iona speci flcat on. The integrated process conltrol System inco rporiltes for exa Dlle italperatutre and( preSSuire sensing and power- and time contr'ol dev ics :iad couiterisedl program mable logic controllers and other control and 1eedi-back and monitoring devices and operators key board and ancilary eqluipmIent and devices accessaryv to control thle complete manlufacturing process throug11hout all stagems ol lprodultct p~reparation,. processing and packaging in accordance with a predetermlinled. aldiustable. progrmmni-able, processing time profile.

The control system incorporates thle f'ollowing basic f'eatures: 1 Mter Control inludII~i nl- ierL'lMCYc Shut~down o t1 111c malinls 1p\\'er- Stpply to the production mlchlinlc inludII~ing' theC supl)Iies to thle varOios sub-systemns electrical and control paincls in Steps I to 4.

2. Hard wired and signmal inputs from machi uc salfety interlocks and sequence interlocks for example from InaIIIIM1* mi ooling" systems. conveyors, product feed, acceSS d1ors. hci tilpl SYSicllI.

3. Input signals f'rom remote sensing devices inctiding produLct surface temp~erature measuirements, heat pumps drying air DB temperature and h ti city. processing chaimber prisu res. conveyor speeds as applicable.

4. Inpuit signal transi tiers and con Verter, to feedbamck signal formn to match thle particlakr still-SNsteml' Co1111-l reqtili lInent..

Programnmable microprocessors for thle pre-setting o1' stib-system controls and process operating' iloces, for cmi\ample mlagnetron ouLltput power and profile, produIct surface temlperat tire and processing chamber at mospheric dry btill[ teinperata rcs. htimiiditby and precsstires.

6. Feedlback signals from~ StIb-Systems and converters to) provide display of ndi viduial imagnet ron power and comapart ment miagnlet ronl power profilIe, procLICt surfIace tepria'sand processing environmnt dry bulb temperatures humidity and llreSStii'c relativef to pre-set conditions th rouighout the production process.

7. Central isedl f~atit inadicaition. di slpiv and alarms.

WO 96/02153 PTA9/01 PCT/AIJ95/00418 This control systemi may use comminercial 1V ialililhle COntrol0 equ~iliment Mid ancillary devices.

Vapour Extra ction/Condlensin g Heat Pump System Processing Steps 2 and 3 of the inven11 ClIoech inLorporate t vap)o(Ir evacuation heat PUMP systeml to aUtomatically control the processing en vi ronnment inl t hat Step to pre-set adjustable conditions of dry hulb inprtu chaminber in il irl hiumidity and processing chiamber pressure. i-an gint gfrom i nospheric pressuire to stib-atniosphieric pressures. Each inlde ick aiir/\apLir01 extract01 onSyStemI and heat recovery and transfer assembly of one or more ci rculati ng, fanls aind oile or miore heat recovery andl transfer heat excha&!oers to circulate and conltrol thle tempIIerat iire and~ hu m11id itY of thle return air/vapour1 returnied to the prod uction chiambers and ito thle vapo ir condensing heat pump assembly. Typically there is p~rov'ided a refrigeration coi Jensing heat pumlp assembly contprisi ng one or miore refrigeration k' m lres~sor. evaporators, condensers, circulating fanls, vapour by-pass dampers, heat exchangers and ancillary equipment and interconnecting pipeworks and coitrol systemi all borining anl integrated sub-systemi component of the pret'erred p~roduction systeili. T[his many comiprise a closed cycle vapour extraction/ condensingt refl-ioeration system to evacuiate moisture and other cooking and dryingO vap)ourS from11 the f~inal l)roeeL!SSIlk ng stagle Cookinrg and drying compartments designed to mlaintain thle pre-set process amibient pressuire and temperature conditions and to ehliinaIte -Cnly odours or other emnissions to atnmosphere.

There is envisaged a heat lutimp systemn inl which the heating energy to heat the dried recirculating" amibient air is reclaimied fromn the reject ion heat of the vapouir condensing cycle and elevated to its operational teniperat ire wholly or mainlly by the reclaii and Use of waste heat generated by the mlicrowave iilagnetrton units incorp~orated inl the process stag~es.

The eqtuipment componentry Of thle vapouMr extrac.tion heat puilil) systemi to process the range of lprodLtict applications described inl tile invention is shown inl Figs. I I(a) and By way of example typical refrigeration suIctionl teilerature ranges from to +5'C and condensing temperatures 40' to but lower suction temiperatures and higher condensig temiperatures mayt he uIsed.

WO 96/02153 PCT./AU95/0418 64 Hot drying air having evapora ted mfii re Irom the product bein t processed is evacuated from the processing chamber in a partly sat u rated Condition, typically above saturation and at a leavimn- temperainre TI typically 40-6tu'( for example in agricultural product processing.

In normal operation this air passes through a sensible heat transfer heat exchanger of the plate type or preferably of the rel'igeration heat pipe type where sensible heat is transferred from TI air sitreamn to T air stream when the former is at a higher temperature than TS.

Air at a reduced temperature T2 hbut with the same moisture content of T1 leaves the primary side otf the sensible heat tiransfer heiat xchnliaer. Depending on the temperature of this air. for examlple beig mllore han 5 above the climatic wet bulb temperature in the area or containing low temlerature condensable vapour compounds or particulate matter. passes throlugh a direct contacltt dehumidifyino heat exchange air scrubber or bypasses this equipment and enters thile heat piI)mp dehlumidifying air handling unit at temperature T3 at an increased saturated condition or at T2 temperature as applicable, The heat pump clehumidifying apparat ius incorporates a condensing evaporator coil preferably equipped with air to water run-around heat exchangers (recouperators) to reduce the evaporator coil air inlet temperature 'T4 to the lowest practical saturated temperature condition by by-passing a controlled proportiol n of tilhe air stream sensible heat around th le evaporator.

The refrigeration heat pump comnplressors Olper0ate under conventional capacity step control to maintain the discharge air temperatiure T5 from the evaporator coil to a fully saturated condition with a dry bull)lb temlperature typically being 5-8"C above the design refrigerant suction tem peratuITe.

Debum idified low temperature air T5 then passes thIirough the downstream run-around sensible heat transfer heat exchanger and(l leaves this heat exchanger at an increased temperature T6. typically 10 to above TI depending on thile enterin condition T2 or T3.

The required humidity of the recirculating air ultimately admitted to the processing chamber at temperature TI2 is controlled by by-passing a proportion of air T2 or T3, as the case may be. around the refrigeration evaporator and run-around heat I I II WO 96/02153 PCT/AU95/00418 exchangers. to nix with air T. his results K111 r bLI incrcased to a temperature T7 and havint, the required absolute humidity misture content required in TI2.

The dehumidified controlled moisture air '17 is dra\ n by a variable speed ft'an to discharge T7 air through thile prillmary air cooled c iIndenser after absorihing the fan heat.

The refrigerant heat energy in the' 1'0-rm of Ia refrigerantl gaU.,s generated by the condensation process on the evaporator coil is transferred via tie condenser to air T7 the temperattire otf which is increased to T. Load balancinu is achieved through the operation of the secondary condenser.

The heated dehumidified air TX then passes throung the secondary side of the sensible heat exchanger (primary side T) and depending on the timnperature of T2 relative to T8 will increase the temperature of TX to TY.

Air at T9 passes through a vacuumin pumup blo\\ er nllit. This apparatus controls the volu me of air delivered to the processing chambier and the bleed volnime delivered to atmosphere to maintain the processin chamber at thile pre-set pressure condition.

The air entering the vacuum blower at T19 absorbs the blower waste heat and emerges at an increased temperature 7TI() typically being a 1-2C(' increase above T9.

Air at TI0 then passes throu h ansii ar 1 start-up heaters (Iusing during start-p only) and then passes through alln air to water heat exchanger in which the waste heat generated by the microwave magnetroin cooling system raises thle temperature of TI0 air for example to 50-60' with low relative humidity typically being between 10 to by not limitedl to these temperature and inminidit ranges.

The refrigerant suction temperatures and condensing temperatures and processing atmospheric conditions stated are by way of examiple only and relate to typical processes involving cheeses. mlleats. fruits and other ag riciultural p)roducts. The heat pump and environ mental control system as described and shown inll Figs. I 1(a) and (b) can be used to satisfy widely varying process relu irei enis.

Heat Pump System Control and Feedback Mechanisms The heat pump evacuation/condensing sub-system described and indicated in Figs.

I1(a) and uses industry sta ndard sensiHnI ad siTnail transmitting devices for the measurement and, feedback ol' the process \ironllllient temperature. humidity and atmospheric pressure. Standardl indlusirN microprocessor control systems and Wo 96/02153 WO 9602153PCIT/AU95/004 18 controllers (Ind act uaors are uised Imw the cont rut o I vat \es. Ily-pass damnpers. variable speed fhn1s, pj)U npS and re frigerat01 i oncoinpreS.Sor Cill)aci~ IVconI rotS.

In practice thle optinmuiii environinent lrocesmiug conditions for the processing of a particular product will be pre-determined by thle physical, chemiical and dielectric properties and the processintg charactecrist ks and end product speci ticat ion of that product.

Thle control system enables the pre-set dry bullb temiperature and huniliny of the air entering thle processing chambner (T 12) and tile pre-set operating, atilmosphieric pressure of the chamber to be miaintained at Ole pre-set conditions. Feedback signals are provided by temiperatuire and( hiidih tCIS0" scusos usiI lla the in let ot' TI 2 to the processing chiamber and by lprvs~SMr di tffeenitil 1mI.-easureent between TI an(] atmosp~heric pressure at exit fronl the chain lber an1d for' thle measHureent of product surface temperature in the processing chamiber (see Figs. I l(a) and The processing envi ronnment heat pumip systemn Cor Step 2 is normialty bie set for a different set of processino conditions then b'r Step 3. The systemis for each Step operate independently and can he re-me indlependlenty 01 each other.

Thle optimumi processi ng environ mciii condition,, and the temiperat tire difference (if any) between the product sui11la.Ce teinplera1t11 1111ad tile (try bulb) teinperat tire of the processing elivironnment are pre-set for each Step. T'his temiperatuire difference is mnaintained by controlling tile mlicrowave illlu power in cacti Stell when operatiiig at coordinated pre-set conveying speeds.

In other examiples where thle processing environmeit temiperature is of lpriiiie importance for product qual ity' coiitrot or- other processi m reasoins the control systeml allows for thle pre-set environmient coniditions to hie re-set during prodLicti0ii and then automnatically iaintai 11CC! The cointrot o01 the i crowa~ e iniput power responids to tile changed envi roiimental condi tioins to inlainta*14 thle tire-set di ffereintial temiperature (if any) betweeii the envi ronii n dl~lIcrN bot) teimilioe aiid tile proCdLucI surface temperature. These sett inlgs miay vary for each Step.

Examlples Description Of Processing of Examples WO 96/02153 WO 9602153PCT/A1195/004 18 6 7 The equipnment used for1 PrOCeSSi11 ng Itinl)lC% 1 -7 comprised: 1000 watt variable power icrOWvI (W eoenl fillt. td ith separatilely step control led 1500 watt ceraic in Iraret raldian1t lIeaterI Wi11 tiiadJ usU' IC p i at tOrml to place tile material at a pre-clciermined distance frlomi thle radiant he~ater.

1000 wan variable power inicrowaive oven fitied wli ita controllable return to zero product lirntable and separately control led mode stirrer to evenly distribute the microwave energy Iil the procevssing chamlber.

digital scales for mleaSu ringi wei2h i ol star imiteri-a and end prod uct weighlt.

temperature probes and dry aid Wet bhti llielinotaters f*or measu rimii tilie oveni ambient ternpleratuore anid Iiuffliid ity an11d 110ird ut internal and surface ternperatures.

microwaveable lprod oct COIItailner-s to hold theC SMple n'liaterial1 d uring the processing, stages.

dual container hot water melting pot to conivert solid sample material into a viscous starting material at theC tempe)ratures noied in thle Schieduile of Examples.

i ndependent laboratory analNS Ofe start ',111d final, pro0diuCt material.

Methodology The sample material was sourced tromt cool solid cheese blocks held inl vapour sealed plastic conltai ners atl 4"'C bulk temperittire.

For viscous material thle start iaIterial1 Wats fi rst conlverted to a viscouIS form at thle reqoi red tempileratutre by using, tilie mlel ii ni pot lolted ill (1 abiove.

The samle matterial iii the measuired weighlts and formt noted was then p~laced inl the pre-processi ng equ ipmitent dlescri bed in (at) above.

This equipment was operated at atmlospheric pressure. whilst irradiating the samiple at lowN. 10% tiliCrowave powver settlig \vitl vatying distances of' thle product below thle infra-red radiant heater and at viryinio ti niC.S ol' eXpOSUre. Processing timie WO 96/02153 WQ 962~5~CIV/A U95/0O4 18 and chambi er tern peratr mit n iLl n d,1(its andi jpro dneiti srrace ternperiat nrc and prod uILct bulk temperaturfe were mleaSUred a th1I. Ytart. 1111d 1)01111 IIIL 011 compion11 Of ilS initial1 processing step which equaies to Step 2 of thle invention process. The dlata given for the Examples 1-7 relates to thle steady state protccssino conditions achieved for each sample.

Onl comp~letion of' Process I) thle maiterial wats iinediately transferred to the final processing stage equipment (h This process wits carried out Under atmospheric pressuire conditions with f~Ll I miCr-OWa\' power alt 1000 Mitts inpu)Lt and measured processing envi ron ment temperatLire 4111d hu ~li di t The processing ime and chamber temperature and humidity and prodUCt Sulrtace teinlperat nrc and product bulk temnperatuire were taken at thle coin licemelnt. mIid point andl on completion of this processing, Step) which equateCs to Step) ot' the invent~on. The clata given for the Examples 1-7 relates to the sicaady state pructssing- conditlions achieved for eachi sample.

The data for the respective samples I to 7 ref'erred to in the Schedule of Examples relates to thle temnperatureC. humII'idity al pressure parameters noted in thle invention process as TO0 H( I and I etc.

The corresponding data for the Examples i -7 was as follows: Parainei Example I IExmple 2 lEXIampleA 3 EX-ample 4 Examupic 5 Example 6 Exmple 7 er Cheddar Cheddar Cheddarm Romanio Roma no Pepamlo Pepa lo cheese, Cheese, Chee-se. Cheese, Chiese, checese, cheese, solid 100-~ viscotis v'iscolls solid 25,, viscous solid 50,, viscous Sample I OtOh± I titig I t)Li- 100--J 50u, 100O± Weight Presentat Slicc 101m, \'Iscuum-,1ir1i,\'±'tit 11-ii C~ut- VI"Lk~ialpI-1 C'uht- Viscolus ion foirm thick Smin thick 8iinn ihict, 8mm i lic.k Strip 8 min thick T(O) 40C 4 0 C .4t'C 4C 4"C 40C 4 0

C

T(l) 5 0 C 501C 5)LC I WIC 50 C 60 0

C

T(2) 1811C 32-C 3uC 2 C 2 1OC' 38 0

C

T(2) S7uC (10-C 371V 03'C7 W5C 65 0

C

POCTA1095/00418 WO 96/021,53 25 C 65 C' 7o C 41.5' C 7' 42"C Tota I 110 60 357 0 12 0 Process Tim e(2) Distanic SO i0 5w SO below I R heat es (I 500W except for 8 12W) mm T 66uC 07'C 5C 7, 1 "5 C 72 0

C

T3' 85 0 C 84 0 C 8 1"C' 87C 1016C 4C 83 0

C

m2 78 0 C 780C 70'(7 gooc 92 0 C 69CC 77 0

C

Total 249 138 20W2 8.5 106 120 ,Process Ti me(3) I) 65 616 02 00 .50 005 H(2) 6030 35 60 35 .5 P(J)I an i in i atil I alim I amil 1 (2 I t iI ai ati I a li l I a li l I a i mn P(3) I atim I I a I aim alim alim atim alm WVBD(3) 36 36 3353 40 3o T(3) 7TV 60C C( 141C WO 96/02153 WO 9602153PCIT/AU195/00418 *1VBD=%VCt hib depre'ssion ENxa11Inpk 8 This test example wits ca'rried outl uIStl illl uilrdutrilS1 inicrowiive processing machine equipped with continluously variable microwave power control. processing envi ronlmen t humidlifty and preSSure control0 1and set upl With prec-processi ng by in fra-red radiant heating and microwave radlation. The sample mierial was ii molasses based raw material wvhich exhibits similar proccssinrg characterist 1Cs to ch~eeSe balsed pr-oducts.

A number of tests were carried out tisin-o di tterent in ira-red and microwave power inputs and proceSSil2 nl imles. IXamle)I S iel 1 2(1 kg sazmple material and wits typical of many tests. The linliShed( produILct had Iless than 2.517% mloist nre content and was at crispy crunchy Open Cell ia c01)OmSa il.

As in the case of the other Examples thie mleasurement of' the product temperatures and processing environment conditions of tell) rICIIU re, hum11idity anld pressure were recorded throughout the process and are summinarised as follows at the stabilised processing conditions for Con1tinuLouIs IprOdltItOii.

The data was as fbi lows: Sample Material 20 kg- Presented lorm E--xtrudedCL 200 mim wide x 20 inmi thick T(O) 0 C 32 T(l) -C Microwave capacity iti Step 2 2 0 K W I 100%'Y) Infra-red capacity in Step 2 12 KW (4 x 3 KW) T(2) 0 C 64 T(2)1 0 C 7 2 0 C Distance below in fra-ted heaters j1501 rim WO 96/02153 WO 9602153PCT/AU95M*418 Process time in Step 2 (seconds) 145 Microwave capacity in Sitep 3 30 1KW I 100%,) T(3) 0 C 92 T(3)1 uC I T(3) 2 OC 9 8 Process time (seconds) 215 H(l) H-1(2) H 2 P(l)I t P(2) 1-250 Pit P(3) -500 Pa WBD(3) 0 C 2 uC; 18 LiJ3 36 WBD(3) ExampIIle 9 A nu1.mber of' crispy crunIIchy celluklir cheese snack Irrudlucis were lprodLuced from a variety of' cheese and cheese based starlingi maicrials In both viscous and solid start condition and of' di flerent WCighis. shiapes. and sizes and starting tem peratutres ranging from 4'C to 90"C. In exccss of' 50 sample products were produced in a process incorporatim, the processing steps Of llhc in\C161 en Wn a wel S inlu1ding Mn initial step for the preparation and presenI1tationoil ithe star miiaterialIfollowed by anl initial processing Step inCIluing1 microwave and in h- red radiant heating and a final microwave processin rgStep) Under at115)ei nd subI-at mosphieric pressure Conditions and in different combinations o1f these processes. rhe processing eqUipnlent uised com1pressed a com1bination 01 (l domeStICicnd i r(i St rial microwave processing equipment as described operating under controlled conditions.

WO 96/02153 WO 9602153PCT/AU95/004 18 72 By way of example a tyjpicaI anl 1, o products was measured ais ~ol lo% s: ili hv heese start ii e, material aind samplle Ilemi Shirt I Tpical Sample Pr:oduicts Fat j 32a34W m.3 Moisture .14-37YW 3. 6 Salt I 4 1.W 3.2 On Dry matter (other) 29-3 1 W 5 9 pH 4.5 -5(0 Fat inl dr- matter 50-54W fX 3 7. 7 The sample products across thle rangv of* shapes aild sizes wvere open cellular slightly Puffed and of crispy crunchy textutre,, I ight meight and tasty.

The average loss in weighit between the finished product and the sheet material roughed from 40% to 5604. depending imial onl the moist nre content of* the start material and fat content.

Depending onl the degree of' pu ff'il" (WhI w ichs con t rolled by theC pr'cess) the vo1letric increase of the sampille produccts with resp~ect to the voIl Iime of' the Start material varied between 47% and 282WY(.

The physical form. weight. shape anid c(tillenstos of thec startinrg material was recorded for each Example together wit i processing ambienlt conditions. produict temperature (bulk and surface) ,infra-red and microwave power levels and process residence times in each processing step. Also fhia p rodunct weighit aind d cl en si oils.

The resulting' data haRs establllished the typical processing relatiotnships between the start product variables and t he inlctowaV powver input and process residence time for the specific produILct ptodu11ction ProceSSing d ilt relating ito three exampiles in this groitp of' tests is cletai led inl E-xamlples I to Lxiiiple A series Of produLcts wet-C jl-rodicefd from a. "'I'asty Matured Cheddar Cheese" start material in solid and viscous form and( of different weights anid sizes. The p)rod~ucts produced were unlifol'(Iv conformaii~blY open c-ellular crisp\ crunchy' cheese snacks WO 96/02153 PTA9/01 IICT/AU95/00418 7.3 which mai ntined a Si milair wLcit Ihl l ZITY iti rcssars range ot* processing temperatures from 66- to 90U' C and residefnce mr ics ra Cieroin 88 seconds to 240 seconds.

The end products were slighlt ly pu11fled depending onl the extent o* in fra-red preprocessing. The start materi-al and finlished( pro-duIct anal])SeS Was aIs tollowAs: If en Si'l' a i ''pica I Samiiple Pr-oduict Fat in dry matter 50-54% 37. Moisture 4 -38~ 4.7 W Tota solids 62-66W 1 95.3 1X I I_ A siiIlar range o 1' products ats noted in I~xariplc 1(0 w\ere prod uced inI Example II using a "Roniano checese as thc stmi iliu igInateriat.

These samples were processed over a ing of11L 11 1emIlieraturesC f'roml 70'C to I 25 0 C to produce a range of highly lput'Iedcl ceese "cookies1" anld hun1s' Of' thle openl cellular crispy crunchy form Depending onl tII KinduLCed degree of' puffing" the cellular structure varied over at ran-e 1rI Ii nloriu op)Cn cells to roughl stirlfCice textlure with explosive P11 flIed openlings. TheC comlmarative analyses ofI these samples was a follows: A i lvs i.s myi Fat in dry matter 38-4 1 Y 38.0% Moisture 38-4(W Total solids (10- L 92.0%1 The processing data relating to these tWO eXiIInpeIC InI this series of' tests are as for examples 4 and( Examiple 12 A further series of' roduIcts were prodceLd InI the samle range as for Example 10 but using "Papato" cheese as thle start material.

WO 96/02153 PCT/AU95/00418 74 These samples were processed ove, at ratnge ot tem peiratu .es 1'romi 05-C to 9 OuC and produced a rancge ol' open celLil S l igt'111 pull erIsp cheese snack products generally similar to Examples L) and 10U. The comparia e analysis of these prodLucts was as follows: 11Ite Stat F *Ipicai Sample Products M~aterial Fat in dIry matter 48-51l' 25 0 Moisture 38-400/ 5.0 OX Total solid."t)-20 L) i5 0 IX The processi nit data relati nt- to two exam lples III 1li1s series of' tests Is ats for examples 6 and 7.

SlhtApe III Examiiivs 9-12 Cheese Snack (Cracker diff~erent shapes and siz/es oencraly lv eo\ 50nm x 50nm nor 50 imm diameter.

Cheese BiscuIis and Warfer-S Any shape and sizes, typically up to 15111 X~i 100111111i hut sayt) Size to suitI commercial market.

Cheese "Cookie" or "Scone" Typically less than 9Gm in daiameter- and l)W lied to open cell liar to scm i-spherical shape or form. Putffed I 5-19 iin in height.

Cheese Bun Highly puffed. Typically miore than 8t0in dam neter and ptied to 2-5 iin or more in height.

E':\amipv 13 This example relates to an industiml a11nia teCed pm-duIct comprisin, a SLuar cane molasses base material and add it iVV'S ot* 1101.i nMill bran and pollard and calcium i hydroxide in the approximate proportions: Molas.ses 74 W,.

WO 90/02153 WO 9602153PCT/AU95/004 18 M~ill l'011 249 The typical analyses o01 molasses 'is: sucrose 1 Y Re~dlUcil UL"Ila 1591 inorganfic products Organlic products I5 W,.

Sample products Were prod uc~ed t'rom11 I ViscouIs starting material at at temlperature ranging troml 20-40, C IntroduCedI 1111r-01.1n1cxi Zd 1 dev'ice inl the form of cylindrical pellets, con rtinuous strips andl larg"e 1)1Semiit form.

The processing of' thle material walS carri1-ed outl nuder cont rolled at mosphere temperature and humidity at sLab-at mlosphleric' pressuare in the nge froml 250- 1000 Pa Vacuum.11. The Surface temperature ol* thle materil waS COntro1lI led been 80-1 1 5'C uinder various microwave power inputs and conveyvor speeds. The sample products were puffeci to varying degrees depend i u onl the pllys cal loran1 Of 1 he entiry material and in p~articualar the surface area versus thle voIlume of' the entry material. All start material was reduced to a moisture content of* less than 2.5 '4 ot tlimnl product weight and had anl open cellular structure and crispy nature. The average 2 I 91' reduction inl weight1 during processing was dite to thle reduIction inl \vater- content and)( some losses of low temperature 111.111 and wIX Volati u. Tlhe proLessing1- diat relatingt n xml nti group of' tests as as per examp~le 8.

Animal feed procLIact in pellet form-I typically 20-30mm dliamleter and upl to 50mm in length. A biscuit t'0111 is ty'pically in SCII Oar ot rctangular11 form inl anY dimlensions to suit marketing. Thie produact ('anl he hart 1Crlf IruceSSed by1 11amlllll ncr illing" inato a stagar like "Pou rable mc rateril Ias aI feed a-ilit i e.

1-'ilmlle 14 Ftarther tests have demonstrated tllat this process (lescrihed iai the invenltion is for example suitable for thle clryiaig of' lprOdltctS suIch aIs aea1s. fish, lpotatry, fresh fruits, such as berries, vinecrops.

WO 96/02153 PCT/AU95/00418 These prodiucts a~re all sensitive to dri ~conditions and inl particukit' dryino conditions which cause deterioration or hardeni ng or dIiscolouiration o1' thle sufatce of' thle produlct.

The control led processimti en vil011VI ro nt old t n m'h and athi IitY t0 C0nt]ml thle surface temperature of the product and thle microwave inlput energy enable the above produLcts to be dlehyd rated whilst r-etiingll theL L ual i t of theC frleSh material inl termls Of colour, textUre. skin properties, fla1vour an1d low volt IiSat ion temperat tIIire aromatic Co rnpou itch s.

Claims

1. A process for removing moisture from a material without substantially spoiling the material, said process comprising: subjecting the material to a controlled humidity environment, said environment being at a temperature and partial vapour pressure of water which do not spoil the material, and, in which the partial vapour of water of said environment is below saturation; irradiating the material in the environment with an amount of microwave irradiation effective to increase the moisture at the surface of the material whereby the vapour pressure at the surface is greater than the vapour pressure of the environment whereby moisture is transferred from the surface to the environment, wherein the amount of said microwave irradiation is not sufficient to spoil the material; and maintaining the temperature of the environment, and, (ii) the partial vapour pressure of water of sa:d environment below saturation, whereby the material is not o 15 spoiled during step *said amount of microwave irradiation being sufficient to substantially maintain said vapour pressure at the surface, until a required amount of moisture has been removed from said material, without reducing the surface temperature of the material more than S 50% of the wet bulb depression of the environment.

2. A process of providing at least a partial barrier to moisture vapour transfer through the surface of a material and for removing moisture from the material without substantially spoiling the material, said process comprising: providing at least a partial barrier to moisture vapour transfer through the surface of a material without substantially spoiling the material, said process comprising: subjecting the material to a controlled temperature and humidity environment, said environnant being at a temperature and partial vapour pressure of water which do not spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation; irradiating the material in the environment with infra red radiation, said amount of infra red radiation being sufficient to at least partially seal the surface of the material to provide at least a partial barrier to moisture vapour transfer through the surface of the material without spoiling the material; and maintaining the temperature of the environment, and, (ii) the partial vapour pressure of water of said environment below saturation, whereby the material is not spoilt during step and removing moisture from a material without substantially spoiling the material, said process comprising: subjecting the material to a controlled humidity environment, said environment f RA i being at a temperature and partial vapour pressure of water which do not spoil the [N:\LIBHIOO116:RRB I I L 78 material, and, in which the partial vapour pressure of water of said environment is below saturation; irradiating the material in the environment with an amount of microwave irradiation effective to increase the moisture at the surface of the material whereby the vapour pressure at the surface is greater than the vapour pressure of the environment whereby moisture is transferred from the surface to the environment, wherein the amount of said microwave irradiation is not sufficient to spoil the material; and maintaining the temperature of the environment, and, (ii) the partial vapour pressure of water of said environment below saturation, whereby the material is not spoiled during step said amount of microwave irradiation being sufficient to substantially maintain said vapour pressure at the surface, until a required amount of moisture has been removed from said material, without reducing the surface temperature of the material more than of the web bulb depression of the environment.

3. The process of claim 1 or claim 2 wherein: *said amount of microwave irradiation being sufficient to substantially maintain said vapour pressure at the surface, until a required amount of moisture has been removed from said material, without reducing the surface temperature of the material more than o S 230% of the web bulb depression of the environment. 20

4. The process of claim 1 or claim 2 wherein: said amount of microwave irradiation is sufficient to substantially maintain said vapour pressure at the surface, until a required amount of moisture has been removed from said material, without substantial reduction of the surface temperature of the material.

5. The process of any one of claims 1 to 4 wherein step comprises: subjecting the material to a controlled temperature and humidity environment, said environment being at a temperature and partial vapour pressure of water which do not spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation.

6. The process of any one of claims 1 to 4 wherein step comprises: subjecting the material to a controlled pressure and humidity environment, said environment being at a pressure, temperature and partial vapour pressure of water which do not spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation.

7. The process of any one of claims 1 to 4 wherein step comprises: subjecting the material to a controlled pressure, temperature and humidity environment, said environment being at a pressure, temperature and partial vapour pressure of water which do not spoil the material, and, in which the partial vapour F pressure of water of said environment is below saturation. [NA\LIBH100116:RRB 'I

8, The process of any one of claims 1 to 7 wherein in step the temperature of the surface of the material is substantially the same as the dry bulb temperature of the environment.

9. The process of claim 2 wherein step (13) comprises: simultaneously or sequentially irradiating the material in the environment with infra red radiation and microwave irradiation, said mount of infra red radiation being sufficient to at least partially seal the surface of the material to provide at least a partial barrier to moisture vapour transfer through the surface of the material without spoiling the material, and said amount of microwave irradiation being sufficient to cause a slight lo positive vapour pressure within the material to prevent the material from deflating, wherein the amount of said microwave irradiation is not sufficient to spoil the material.

The process of claim 2 or claim 3 wherein step comprises: subjecting the material to a controlled pressure, temperature and humidity environment, said environment being at pressure which does not spoil the material. 15

11. The process of any one of claims 1 to 10 wherein the material is selected from the group natural and processed cheeses and dairy products, meats, fish, poultry, fruits, berries, vine products, herbs, condiments and spices raw material, vegetable produce natural and semi-processed including marine algae and plant products, cereal grains, oil S°seed, nuts, seeds, nodular and granular products, agricultural produce waste products: 20 chemical compound recovery-citrus fruits, grapes, agricultural waste, paper pulp products, wood chips, wood shavings, sawdust, dehydration of chemical powder compounds, sugar cane and molasses including sugar beet process molasses. te

12. The process of any one of claims 1 to 11 wherein the material is selected from the group consisting of natural cheeses and processed cheese (which may include other additives such as carbohydrates, cereals, proteins, meats, fruits, nuts, minerals, vegetables, colouring, flavouring, sodium and non-sodium emulsifiers, condiments, eggs, spices, and smallgoods, and other additives, may be included), including low fat cheeses and cheese based mixtures and including for example all cheddars. Colby, Swiss processed cheese, condiments, spices, marine algae, marine plants including seaweed, protein sources such as egg protein, soy protein, milk protein, gluten or ceseinate which may optionally be emulsified with plant or animal fat or oils such as soybean, sunflower, peanut, olive, canola, safflower or palm oil, together with other components and water, cereals including wheat, rye, corn, rice, millet, sorghum, maize, barley and oats, nuts including peanuts, almonds, cashews, hazel nuts, macadamia nuts, walnuts, flesh of prawns, shrimps, yabbies, Balmain bugs, pippies, flesh of turtles, flesh of tortoises, eels, octopus, squid, flesh of lobsters, flesh of crayfish, flesh of crabs, marine mammals and fish including hardiheads, white bait, mullet, sardines, salmon, tuna, trout, bream, black fish, flathead, tailor, John Dory, schnapper, trevally, sweep, shark, garfish, pike, leatherjacket, wrasse, mulloway, dolphin fish, kingfish, belennies, gobies, toad fish and A 4/ other like fish, plant proteins and/or polypeptides from rice, barley, oat, rye, corn, wheat, N:\LIBH100116RRB -II I animal meats and poultry including, beef, chicken, pork, rabbit and turkey, flowering plants such as rose, iris, carnation, daffodil, lily, vegetables such as cabbage, cauliflower, peas, beans, such as soyabeans, lentils, mung beans, lima beans, kidney beans, adzuki beans, and broad beans, broccoli, brussel sprouts, peanuts, chickpeas, asparagus, soya extracts, natural and processed dairy products, fruits including apples, bananas, apricots, plums, cherries, pears, pineapple, vine products including grapes and dates, fruit skins including orange and mandarin skins, and fruit seeds including grape seeds, berries, herbs and spices raw material, vegetable produce natural and semi-processed, oil seed, seeds, nodular and granular products, agricultural produce waste products: chemical compound recovery-citrus fruits, grape waste, paper pulp products, wood chips, wood shavings, sawdust, dehydration of chemical powder compounds, honey, treacle, sugar cane and molasses including sugar beet process molasses.

13. An apparatus for removing moisture from a material without substantially spoiling the material, said apparatus comprising: means for subjecting the material to a controlled humidity environment, said environment being at a temperature and partial vapour pressure of water which do not spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation; 2 means for irradiating the material in the environment with an amount of 20 microwave irradiation effective to increase the moisture at the surface of the material whereby the vapour pressure at the surface is greater than the vapour pressure of the environment whereby moisture is transferred from the surface to the environment, wherein the amount of said microwave irradiation is not sufficient to spoil the material; and means for maintaining the temperature of the environment, and, (ii) the partial vapour pressure of water of said environment below saturation, whereby the oooo material is not spoiled; Sgsaid amount of microwave irradiation being sufficient to substantially maintain said vapour pressure at the surface, until a required amount of moisture has been removed from said material, without reducing the surface temperature of the material more than of the wet bulb depression of the environment.

14. An apparatus for providing at least a partial barrier to moisture vapour transfer through the surface of a material and for removing moisture from the material without substantially spoiling the material, said apparatus comprising in combination; an apparatus for providing at least a partial barrier to moisture vapour transfer through the surface of a material without substantially spoiling the material, said apparatus for providing at least a partial barrier to moisture vapour transfer comprising: means for subjecting the material to a controlled temperature and humidity Senvironment, said environment being at a temperature and partial vapour pressure of IN:\LIBHI01 1 O:RRB I water which do not spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation. means for irradiating the material in the environment with infra red radiation, said amount of infra red radiation being sufficient to at least partially seal the surface of the material to provide at least a partial barrier to moisture vapour transfer through the surface of the material without spoiling the material; and means for maintaining the temperature of the environment, and, (ii) the partial vapour pressure of water of said environment below saturation, whereby the material is not spoilt; and o apparatus for removing moisture from a material without substantially spoiling the material, said apparatus for removing moisture comprising: means for subjecting the material to a controlled humidity environment, said environment being at a temperature and partial vapour pressure of water which do not spoil the material, and, in which the partial vapour pressure of water of said environment :o 15 is below saturation; means for irradiating the material in the environment with an amount of microwave irradiation effective to increase the moisture at the surface of the material whereby the vapour pressure at the surface is greater than the vapour pressure of the environment whereby moisture is transferred from the surface to the environment, 20 wherein the amount of said microwave irradiation is not sufficient to spoil the material; and means for maintaining the temperature of the environment, and, (ii) the :partial vapour pressure of water of said environment below saturation, whereby the Smaterial is not spoiled; said amount of microwave irradiation being sufficient to substantially maintain said vapour pressure at the surface, until a required amount of moisture has been removed ,o from said material, without reducing the surface temperature of the material more than 50% of the wet bulb depression of the environment.

The apparatus of claim 13 or claim 14 wherein comprises: means for subjecting the material to a controlled temperature and humidity environment, said environment being at a temperature and partial vapour pressure of water which do not spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation.

16. The apparatus of claim 13 or claim 14 wherein comprises: means for subjecting the material to a controlled pressure and humidity environment, said environment being at a pressure, temperature and partial vapour pressure of water which do not spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation.

17. The apparatus of claim 13 or claim 14 wherein comprises: [N:\LIBHIGO11 8:RRB IL II 82 means for subjecting the material to a controlled pressure, temperature and humidity environment, said environment being at a pressure, temperature and partial vapour pressure of water which do not spoil the material, and, in which the partial vapour pressure of water of said environment is below saturation.

18. The apparatus of claim 14 wherein comprises: 0(B) means for simultaneously or sequentially irradiating the material in the environment with infra red radiation and microwave irradiation, said amount of infra red radiation being sufficient to at least partially seal the surface of the material to provide at least a partial barrier to moisture vapour transfer through the surface of the material without spoiling the material, and said amount of microwave irradiation being sufficient to cause a slight positive vapour pressure within the material to prevent the material from deflating, wherein the amount of said microwave irradiation is not sufficient to spoil the material.

19. The apparatus of claim 14 wherein comprises: 15 means for subjecting the material to a controlled pressure, temperature and humidity environment, said environment being at a said environment being at a pressure which does not spoil the material.

20. A process for removing moisture from a material, substantially as described herein with reference to Figs. 2, 3 and 6.

21. A process for removing moisture from a material, substantially as hereinbefore described with reference to any one of the Examples.

22. A process for providing at least a partial barrier to moisture vapour transfer through the surface of a material and for removing moisture from a material, substantially as described herein with reference to the accompanying Figures 2, 3 and 6.

23. An apparatus for providing at least a partial barrier to moisture vapour transfer through the surface of a material and for removing moisture from a material, substantially as hereinbefore described with reference to accompanying Figs. 1, 4, 5 and S 7 to 11.

24. An apparatus for the removing of moisture from a material, substantially as described herein with reference to accompanying Figures 1, 4, 5 and 7 to 1l1b. Dated 23 March, 1998 Microwave Processing Technologies Pty. Limited Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON [N:\LIBHOO1 16:RRB P -L I