GB2329571A

GB2329571A - Method of stoving confectionary

Info

Publication number: GB2329571A
Application number: GB9720431A
Authority: GB
Inventors: Albert Zumbe; Faribourz Kariminia; Willem Brouwer
Original assignee: Cadbury Schweppes Ltd
Current assignee: Mondelez UK Holdings and Services Ltd
Priority date: 1997-09-26
Filing date: 1997-09-26
Publication date: 1999-03-31
Also published as: GB9720431D0

Abstract

A mouldable confectionary composition comprising sugar, glucose syrup, flavouring, water and at least one setting agent, selected from gums and gelatinising agents is introduced into moulds in a stoving chamber (10), the confections are then subjected to a stoving cycle comprising a recirculating flow of heated air aound the unvented chamber (10) until the confections have the desired moisture content, the temperature and relative humidity of the air are controlled by passing the air over condensing (22) and heating (24, 28) surfaces. The stoved articles are subsequently cooled.The moulds may be starch moulds. The temperature is preferably at least 65‹C and the initial ramping rate is preferably at least 1‹C per minute, with the entire cycle lasting from 12 to 24 hours. The stoving may be effected in two or more stages at different temperatures, with the temperature being reduced by 7 to 20‹C between stages. The temperature drop may be effected by the introduction of external cooled air of controlled humidity into the chamber (10), via the cooling control unit (30).

Description

METHOD OF DRYING CONFECTIONERY This invention relates to a method of drying confectionery, particularly gums and jellies, for example hard gums, wine gums, fruit gums and jelly babies; and some types of liquorice.

The above types of confectionery are traditionally produced by mixing the required ingredients to form a mouldable composition, moulding (usually starch moulding) the composition to form articles of the required shape, and then setting and drying the moulded composition by a stoving procedure. Hereinafter, for convenience, such types of confectionery will be referred to as "stoved confectionery". In the manufacture of stoved confectionery based on hard gums, for example wine gums, the stoving process is effected in a dry hot room at about 46"C for as long as three to ten days until the required texture is obtained, followed by cooling. With current modern equipment, the stoving and cooling cycle can only be reduced to about 48 hours for wine gums by performing stoving in a vented drying chamber which is divided into zones which are independently temperature controlled to about 58 OC for a heating cycle of about 38 hours followed by a ten hour cooling cycle. During the heating cycle, 10% of the humid drying air is bled off and replaced with fresh warmed air, thus maintaining a low humidity throughout the heating cycle. There is no real control of the humidity and therefore the humidity drops to about 16% which causes case hardening of the product.

It has been previously shown that the stoving cycle time can be reduced by about 27% if a slightly higher temperature is employed (about 62"C) provided that the relative humidity is increased to about 30% during the first ten hours of heating, during which time the chamber is unvented.

For the remaining 20 hours of drying, the temperature is reduced to about 58"C and the chamber is vented to cause the relative humidity to drop over the remaining 20 hour period so as to permit drying.

It is an object of the present invention to provide a method of manufacturing stoved confectionery which enables even greater time savings to be made during stoving.

According to one aspect of the present invention, there is provided a method of manufacturing stoved confectionery articles, comprising the steps of: (i) forming a mouldable confectionery composition comprising sugar, glucose syrup, flavouring, at least one setting agent selected from gums and gelatinising agents, and water; (ii) introducing the confectionery composition into moulds to formed shaped articles; (iii) subjecting the shaped articles in the moulds (preferably starch moulds) to a stoving cycle during which the articles are subjected to a recirculating flow of heated air in an unvented chamber, wherein the relative humidity and temperature of the recirculating air is controlled using moisture condensing and heating surfaces over which the air is passed until the confectionery articles have a predetermined moisture content; and (iv) subsequently cooling the stoved confectionery articles.

By use of a chamber which is unvented during at least part of the stoving step (iii), and which has internal condensing and heating surfaces, a close control to be maintained over the relative humidity and temperature within the chamber. This enables temperatures to be used which are higher than has heretofore been considered possible, with the result that appreciable savings can be made in the overall time required to reduce the moisture content of the product to the desired predetermined level.

Substantial savings can also be made on running costs.

The time employed depends somewhat upon the nature of the confectionery composition. However, the temperature is usually at least 65 "C and may be as high as 80 C.

It is particularly preferred, in order to inhibit degradation of the confectionery composition, to perform rapid heating to the desired temperature. Typically, the heating rate is preferably at least 1 OC per min. The stoving in step (iii) above is preferably in the range of 12 to 24 hours.

In order to prevent unwanted degradation of the composition being stoved in step (iii), it is preferred to perform the stoving in at least two stages effected at different temperatures such that the temperature is relatively high during the first stage and is lower in the second and any subsequent stages. The temperature difference between adjacent stages may be in the range of 7 to 20 OC, preferably about 10 - 15 OC. The temperature may be reduced between these stages by introduction of external cooled air of controlled humidity into the chamber to enable rapid temperature reduction.

The relative humidity is preferably at a relatively higher level (typically in the range of 50 - 40 %) for at least the first two hours of the step (iii).

More preferably, the relative humidity is reduced to a relatively lower level (typically 30 - 20 %) subsequently and is preferably maintained at this lower humidity level for a longer period of time than at the higher humidity level. The lower relative humidity level is preferably started during the relatively high temperature treatment stage referred to above.

The actuai temperatures and times employed depends upon the composition of the confectionery articles being produced. Compositions for producing wine gums typically have the following formulation (in parts by weight): Water 13-15 Sugar 20-24 Glucose syrup 40 - 50 Thin-boiling starch 8 - 10 Gelatine 4 - 6 Gum substitute (starch) 3 - 6 Acid 0.6 - 1.2 Colours/Flavourings as desired Such wine gum compositions may be subjected to either of the following stoving and cooling schedules: (1) 12 hours at 72 "C at a relative humidity of 50 - 40 % for the first 2 hours and a relative humidity of 30 - 20 % for the remaining 10 hours; rapid cooling to 65 OC; treatment for 9 hours at 65 "C at a relative humidity of 20 Wo; rapid cooling to 20 "C and maintaining such temperature for 3 hours at a relative humidity of 20 Wo; or (2) 6 hours at 80 C at a relative humidity of 50 - 40 % for the first 2 hours and a relative humidity of 30 - 20 % for the remaining 4 hours; rapid cooling to 65 C; treatment for 6 hours at 65 C at a relative humidity of 20 Olo; rapid cooling to 20 CC and maintaining such temperature for 3 hours at a relative humidity of 20 Wo.

Compositions for producing jelly babies typically have the following formulation (in parts by weight): Water 12-14 Sugar 45 - 55 Glucose syrup 20 - 25 Gelatine 11 - 15 Gum substitute (starch) 3 - 6 Citric acid 0.4 - 1.0 Colours/Flavourings as desired Such jelly baby compositions may be subjected to either of the following stoving and cooling schedules: (1) 12 hours at 65 "C at a relative humidity of 50 - 40 % for the first 2 hours and a relative humidity of 30 - 20 % for the remaining 10 hours; rapid cooling to 60 OC; treatment for 9 hours at 60 C at a relative humidity of 30 - 20 Olo; rapid cooling to 20 "C and maintaining such temperature for 3 hours at a relative humidity of 20 Wo; or (2) 9 hours at 70 "C at a relative humidity of 50 - 40 C/c for the first 2 hours and a relative humidity of 30 - 20 /O for the remaining 7 hours; rapid cooling to 65 C; treatment for 6 hours at 65 C at a relative humidity of 30 - 20 %; rapid cooling to 20 C and maintaining such temperature for 3 hours at a relative humidity of 20 %.

Compositions for producing soft liquorice typically have the following formulation (in parts by weight): Water 19-21 Sugar 25 - 30 Cane sugar molasses 16 - 20 Glucose syrup 16 - 18 Thin-boiling starch 7 - 8 Colloidal protein 4 - 5 Wheat starch 1 - 3 Ammonium chloride 0.5 - 2 Malt extract 0.2 - 0.7 Flavourings as desired Such soft liquorice compositions may be subjected to either of the following stoving and cooling schedules: (1) 12 hours at 80 C at a relative humidity of 50 - 40 % for the first 2 hours and a relative humidity of 30 - 20 % for the remaining 10 hours; rapid cooling to 65 "C; treatment for 9 hours at 65 "C at a relative humidity of 20 We; rapid cooling to 20 C and maintaining such temperature for 3 hours at a relative humidity of 20 We; or (2) 6 hours at 85 "C at a relative humidity of 50 - 40 We for the first 2 hours and a relative humidity of 30 - 20 % for the remaining 4 hours; rapid cooling to 70 C; treatment for 6 hours at 70 OC at a relative humidity of 20 %; rapid cooling to 20 OC and maintaining such temperature for 3 hours at a relative humidity of 20 We.

At the end of the stoving period, the articles typically have a moisture content which is about 1-2 % above that required in the finished articles.

Thus, the cooling step (iv) is typically effected under drying conditions such that the moisture content of the articles is reduced to the required level.

In another embodiment, the articles are heated to about 80 C in 45 minutes followed by maintaining the temperature for about eleven hours by recirculating the air in the chamber. The temperature is then preferably reduced rapidly to about 65 "C (eg by introduction of external cooled air of controlled humidity) and maintained at this temperature by recirculating the air in the chamber for about six hours. Following this, the cooling step (iv) is effected by introducing external cooled air of controlled humidity and maintaining such temperature for a further three hours. As far as the relative humidity is concerned, in step (iii), it is preferred to keep the relative humidity at about 55-40%, preferably 5040 %, during heating to about 80 "C. During the subsequent 11 hours at 80 "C, the relative humidity is preferably automatically reduced down to 30 %. Such reduction in relative humidity is preferably gradual and the rate of reduction is preferably controlled.

During reduction of the temperature of the articles to about 65 "C and treatment at about 65 "C, the relative humidity is preferably maintained at about 30-20 %.

During reduction of the temperature of the articles to about 20 "C and maintenance at such temperature in the cooling step, the relative humidity is preferably maintained at about 20 %. The temperature of the cooling air introduced into the chamber may be as low as about -4 "C The method of the present invention may be performed batchwise by loading the articles to be stoved as a batch into the chamber, stoving and cooling them and then removing the stoved and cooled articles from the chamber. However, it is also possible to provide a continuous method where the articles to be stoved are passed continuously through a tunnel in which stoving and cooling zones maintained at the required temperatures and humidities are provided.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a schematic illustration of one embodiment of a method of manufacturing stoved confectionery articles according to the present invention; and Fig. 2 is a schematic illustration of stoving and cooling equipment used to effect heating and cooling of a batch of confectionery articles to be stoved in accordance with the method of Fig. 1.

Referring now to Fig. 1 of the drawings, a stovable confectionery composition is formulated by mixing the ingredients together in a mixer M and passing this mixture to an automated starch moulding plant P where printed starch moulds provided in the trays are filled with the confectionery composition. The filled trays are then stacked onto pallets and introduced into a stoving and cooling equipment E which will be described in more detail hereinafter. After stoving and cooling in the equipment E, the stacked trays are removed and passed to a starch buck S wherein the trays are tipped and the confectionery articles are separated from the starch which is then sieved as necessary to remove any residual particles of confectionery before being passed back to the starch moulding plant P for re-use in another moulding operation.

Referring now more particularly to Fig. 2, the stoving and cooling equipment E comprises a housing 10 within which a batch of confectionery articles to be dried under controlled elevated temperature and humidity conditions and then cooled are supported in an array 12 of vertically and horizontally spaced starch moulding trays mounted on pallets (not shown). This array 12 is disposed within the housing 10 just below a false ceiling 14 defining a recirculatory flow passage 16 between it and the roof of the chamber 10. A number of fans 18 (only one shown) above the false ceiling 14 serve to circulate air within the housing 10 through the passage 16, over the trays in the array 12 and through a dehumidification unit 20 which is disposed in the circulatory flow path downstream of the array 12 between the latter and the fans 18.

Within a frame of the unit 20 are cool coils 22, hot coils 24, a fan 26 and an electrically operated heater 28. The various parts 22, 24, 26 and 28 are disposed in the recirculatory flow in that order between the array 12 and the fans 18, with the cool coils 22 being disposed immediately downstream of the array 12. The cool coils 22 and the hot coils 24 are connected via refrigerant pipes (not shown) with a compressor and cooler unit 32 which, with the unit 20, defines a heat pump dehumidification system serving to maintain the desired temperature and relative humidity conditions within the housing 10 of the equipment E in use. Within the unit 32 is a subcooler 32a, a compressor 32b and a fan (not shown).

A cooling control unit 30 is, like the unit 32, mounted on top of the chamber 10. However, these units 30 and 32 may be mounted elsewhere if desired, for example outside the building or room in which the chamber is housed.

The electrical heater 28 is energised for a period of time to effect rapid heating of the confectionery articles within the trays in the array 12 to the desired temperature and is then de-energised and remains deenergised for the remainder of the drying period. The fans 18 cause the resultant hot air to flow at a high flow rate over the trays and encourage the moisture to migrate from the core of the articles and to evaporate so that the air becomes moist.

The relative humidity is maintained at the desired level by the unit 20.

Refrigerant is pressurised by the compressor 32b in the unit 32 and thereby heated. This heat is dissipated into the chamber 10 via the hot coil 24 in the unit 20. The refrigerant is thereby changed from a gaseous state to a high pressure liquid state before being passed to the sub-cooler 32a in the unit 32 for further cooling. The high pressure liquid refrigerant is then returned to the unit 20 and passes through an expansion valve (not shown) where it loses its pressure and is thereby further cooled and passed through the cool coil 22 where it evaporates.

This cools the air passing over the cool coil 22 down to a level where the moisture in the air condenses onto the coils and drains away, thus reducing the relative humidity of the air. The now gaseous refrigerant is then passed back to the compressor 32b and the cycle repeated. For every pound of water condensed over the cool coil 22, 1000 BTU of thermal energy is transferred to the hot coil 24 and this heat is put back into the chamber 10 by operation of the fan 26 to encourage further evaporation of moisture from the confectionery articles. It will thus be understood that the system re-utilises the latent heat of vaporisation of water.

Therefore, the air enters the unit 20 and leaves at a higher level in temperature and a lower level in humidity. This cycle continues and the entire air in the chamber is sampled by the unit 20 in order to dry the air at a rate of once every 72 seconds.

The drying rate is finely controlled by the operation of the compressor 32b. At the end of a drying (stoving) cycle, the unit 20 and the associated components shut down automatically and the cooling unit 30 is operated to cool the articles. The cooling unit 30 has cool coils 30a and operates in a similar way to the unit 20. However, the hot coil (not shown) is situated outside of the building to dissipate heat to atmosphere.

During the cooling cycle, the air is brought in from atmosphere and cooled down to 20 "C below ambient by passing the air over the cool coils 30a. Moisture from the incoming air condenses over the cool coils 30a and the cool dry air enters the chamber 10 and is recirculated within the chamber using the fans 18. The hot humid air is extracted from the chamber 10 via an extractor fan (not shown). This cycle of introducing cool air into the chamber 10 and exhausting hot humid air to atmosphere is continued until the product is cooled to the desired level for that cooling stage.

In a typical drying and cooling schedule, the confectionery articles are heated up to a temperature of 80"C within 45 minutes by the heater 28 which is then switched off. The relative humidity during this heating-up period is kept in the range of 50 to 40%. At the end of the heating-up period, the temperature is maintained for the required period of time, typically about eleven hours. During this period, the relative humidity is reduced from about 50% down to about 30% automatically by operation of the compressor 32b. If the humidity is above 30 /O, the compressor 32b is energised to bring the humidity back down to 30%. It will then be de-energised until the humidity rises above 30%. Reduction from 50% down to 30% relative humidity is gradual and the rate of reduction can be determined by a programmable controller (not shown) associated with the dehumidification unit 20.

At the end of this period, the temperature is reduced rapidly to a lower temperature, typically about 65 "C. This is effected by use of the cooling unit 30 as described above. Following this, the lower temperature of about 65 "C is maintained for six hours at a relative humidity of 30% in the same way as described above for the higher temperature/humidity maintenance using the units 20 and 32.

Following this, cooling of the articles to about 20 "C is effected rapidly by use of the unit 30 as described above and then maintained for 3 hours.

At the end of this c. 21 hour period of drying followed by cooling, the articles can then be removed from the housing 10 and de-moulded as described above.

Example 1 A composition for producing wine gums having the following formulation (in parts by weight): Water 14 Sugar 22 Glucose syrup 45 Thin-boiling starch 9 Gelatine 5 Gum substitute (starch) 4 Acid 1 Colour/flavouring 0.1-0.2/0.1-0.2 is used to produce articles as described above with reference to Figures 1 and 2, with the stoving and cooling schedules being as follows: (a) 6 hours at 80 "C at a relative humidity of 50 - 40 WO for the first 2 hours and a relative humidity of 30 - 20 % for the remaining 4 hours; (b) rapid cooling to 65 "C; (c) treatment for 6 hours at 65 "C at a relative humidity of 20 We; and (d) rapid cooling to 20 OC and maintaining such temperature for 3 hours at a relative humidity of 20 %.

The resultant wine gums have eating qualities which are comparable to those of wine gums produced by the traditional method.

Example 2 A composition for producing soft liquorice articles having the following formulation (in parts by weight): Water 19-21 Sugar 25 - 30 Cane sugar molasses 16 - 20 Glucose syrup 16 - 18 Thin-boiling starch 7 - 8 Colloidal protein 4 - 5 Wheat starch 1 - 3 Ammonium chloride 0.5 - 2 Malt extract 0.2 - 0.7 Flavourings 0.1-0.2 is used to produce articles as described above with reference to Figures 1 and 2, with the stoving and cooling schedules being as follows: (a) 6 hours at 85 OC at a relative humidity of 50 - 40 We for the first 2 hours and a relative humidity of 30 - 20 We for the remaining 4 hours; (b) rapid cooling to 70 OC; (c) treatment for 6 hours at 70 C at a relative humidity of 20 We; and (d) rapid cooling to 20 OC and maintaining such temperature for 3 hours at a relative humidity of 20 We.

The resultant soft liquorice articles have eating qualities which are comparable to those of soft liquorice articles produced by the traditional method.

Example 3 A composition for producing jelly babies having the following formulation (in parts by weight): Water 12-14 Sugar 45 - 55 Glucose syrup 20 - 25 Gelatine 11 - 15 Gum substitute (starch) 3 - 6 Citric acid 0.4 - 1.0 Colours/Flavourings 0.1-0.2/0.1-0.2 is used to produce articles as described above with reference to Figures 1 and 2, with the stoving and cooling schedules being as follows: (a) 9 hours at 70 OC at a relative humidity of 50 - 40 % for the first 2 hours and a relative humidity of 30 - 20 % for the remaining 7 hours; (b) rapid cooling to 65 "C; (c) treatment for 6 hours at 65 "C at a relative humidity of 30 - 20 We; and (d) rapid cooling to 20 "C and maintaining such temperature for 3 hours at a relative humidity of 20 We.

The resultant jelly babies have eating qualities which are comparable to those of jelly babies produced by the traditional method.

Claims

1. A method of manufacturing stoved confectionery articles, comprising the steps of: (i) forming a mouldable confectionery composition comprising sugar, glucose syrup, flavouring, at least one setting agent selected from gums and gelatinising agents, and water; (ii) introducing the confectionery composition into moulds to form shaped articles; (iii) subjecting the shaped articles in the moulds to a stoving cycle during which the articles are subjected to a recirculating flow of heated air in an unvented chamber, wherein the relative humidity and temperature of the recirculating air is controlled using moisture condensing and heating surfaces over which the air is passed until the confectionery articles have a predetermined moisture content; and (iv) subsequently cooling the stoved confectionery articles.

2 A method as claimed in claim 1, wherein the moulds are starch moulds.

3. A method as claimed in claim 1 or 2, wherein the temperature is at least 65 "C.

4. A method as claimed in claim 7, 2 or 3, wherein at the beginning of the stoving cycle, the heating rate is at least 1 OC per min.

5. A method as claimed in any preceding claim, wherein the stoving in step (iii) above is effected for a time in the range of 12 to 24 hours.

6. A method as claimed in any preceding claim, wherein the stoving is effected in at least two stages effected at different temperatures such that the temperature is relatively high during the first stage and is lower in the second and any subsequent stages.

7. A method as claimed in claim 6, wherein the temperature difference between adjacent stages is in the range of 7 to 20 OC.

8. A method as claimed in claim 6 or 7, wherein the temperature is reduced between these stages by introduction of external cooled air of controlled humidity into the chamber.

9. A method as claimed in ant preceding claim, wherein the relative humidity is at a relatively higher level for at least the first two hours of the step (iii),and is reduced to a relatively lower level subsequently.