GB2347338A

GB2347338A - Preparation of batter-coated food products

Info

Publication number: GB2347338A
Application number: GB9904915A
Authority: GB
Inventors: Andrew David Lewis
Original assignee: United Biscuits Ltd
Current assignee: United Biscuits Ltd
Priority date: 1999-03-03
Filing date: 1999-03-03
Publication date: 2000-09-06
Anticipated expiration: 2019-03-03
Also published as: GB9904915D0; GB2347338B

Abstract

A process for the preparation of batter-coated food products, comprises treating the at least partially fried batter-coated product with super-heated steam or hot gas and/or vapour, preferably for a period between 10 sec to 4 min at a temperature between 180 to 230{C. The super-heated steam, hot gas or the vapour is preferably caused to flow over the food product at a velocity of at least 8 m/sec by using one or more fans and the super-heated steam may be formed by drawing steam through a heat exchanger. Preferably the food product is par-fried for a period between 10 seconds to 1 min at a temperature between 150 to 210{C. The final food product is preferably frozen or chilled and the coating may be embossed and preferably has a fat content of not more than 28% by weight of the coating. Apparatus for this process comprises one or more conveyors 2,7 for assisting the passage of the products through batter applicators 1,4, breader 3, fryer 5, air/steam treatment unit 6 and preferably a freezer 8. The food product may be meat, fish or vegetables but preferably chicken or fish and the hot gas may be air and the vapour may be steam.

Description

Improvements in and relating to the preparation of coated food products The invention relates to the preparation of coated food products, and especially to the commercial preparation of batter-coated food products, including those products having one or more layers of coating, the outermost layer of which is batter, and those products, referred to as"breaded", having a coating of batter and an outer covering of crumbs.

Such coated food products, which may, for example, comprise meat and/or vegetable food products but which more especially comprise fish or chicken, are prepared commercially by coating and then deep-frying for at least a short period before chilling or freezing and packaging for sale to consumers. Consumers are, however, becoming increasingly aware of the desirability of limiting the amount of fat in their daily food intake for dietary and/or health reasons.

It is known in the production of potato crisps to treat deep-fried potato slices with super-heated steam immediately after they emerge from the fryer. Such a process is disclosed in GB 1 519 049, in which potato slices are transported through zones of a fryer maintained at a temperature that is initially lower than that used conventionally and is maintained constant, or increases in the direction of advance of the potato slices through the fryer. After leaving the fryer, the slices are, without coming into contact with the atmosphere, immediately conveyed through a device where they are treated with superheated steam to remove fat from the surfaces of the slices. In that way it has been found possible to produce potato crisps having a lower fat content than crisps produced in a conventional manner.

It has now been found, surprisingly, that a batter-coated food product can be treated with super-heated steam after frying in a similar manner to that proposed for potato slices to achieve a reduction in fat content of the coating.

Accordingly, the invention provides a process for preparing coated food products, which comprises coating a food product in batter, frying the batter-coated food product for a length of time sufficient to set at least the outermost surface of the batter coating, and treating the batter-coated food product with super-heated steam.

It has, however, also been found a reduction in fat content of batter-coated food products can be achieved by treating the food products after frying with hot gas or vapour, or a mixture of hot gas and vapour, in a similar manner to the treatment with super-heated steam.

Accordingly, the invention also provides a process for preparing coated food products, which comprises coating a food product in batter, frying the batter-coated food product for a length of time sufficient to set at least the outermost surface of the batter coating, and treating the batter-coated food product with hot gas and/or vapour.

The treatment step with super-heated steam, or with hot gas, which is preferably air, and/or vapour, which is preferably steam, in accordance with the invention will be referred to collectively in this specification as the"air/steam"treatment step. It is possible with such a treatment step to effect removal of fat from the coating of the food products.

The process of the invention is especially advantageous when the food product itself (excluding the coating) is not to be cooked during the process. In such a process, the frying step is such as to act only on the coating, and there is no significant increase in temperature of the food product itself. Such a step is often referred to as"par-frying"or "partial frying".

It has been found in the process of the invention that by frying a batter-coated food product generally for a time within the range of from 10secs to Imin, and preferably within the range of from 20 to 30secs, at a frying temperature within the range of from 150 to 210 C, preferably from 190 to 210 C, and then subjecting the product to the air/steam treatment step, a batter-coated food product can be obtained in which the coating has a lower fat content than a similar product that has been fried in a conventional manner without the air/steam treatment step. The frying time depends on the frying temperature (that is to say, the temperature of the frying medium), but, at a given frying temperature, the frying time in the process of the invention need only be sufficiently long for the outermost surface of the batter coating to set, or a skin to form, to enable further handling of the batter-coated food product without undue damage to, or distortion of, the coating. The frying time in the process of the invention may therefore be less than in a conventional par-frying step, with a consequent reduction in fat absorbed by the coating.

Fat is also removed from the coating by the air/steam treatment step, which can act not only to remove fat from the batter-coating, but also to finish cooking of the batter, resulting in a crisp end product no less attractive in eating quality to a consumer than a conventionally-prepared product, but with the benefit of a lower fat content. It is possible, with the process of the invention, to produce a batter-coated food product in which the coating has a reduction in fat content of up to 40% by weight Unlike the preparation of potato crisps using super-heated steam as described above, in the process of the invention it is usually unnecessary to take special measures to ensure that the batter-coated food products do not come into contact with the atmosphere after leaving the fryer and before undergoing the air/steam treatment step.

It is preferred, however, that the fried food products are not allowed to cool to any significant extent after leaving the fryer and before being so treated.

The fried batter-coated food products are advantageously treated with super heated steam, or hot gas and/or vapour, at a temperature within the range of from 180 to 230 C, preferably, 190 to 210 C. That temperature can be measured using, for example, one or more thermocouples arranged adjacent to the product surface.

The super-heated steam, or hot gas and/or vapour, is advantageously caused to flow over the food product at a velocity of at least 8m/sec, preferably, not more than 25m/sec, more preferably, within the range of from 15 to 20m/sec. That velocity can be determined using an anemometer positioned adjacent to the food product.

Each of the batter-coated food products is advantageously treated with superheated steam, or hot gas and/or vapour, for a period within the range of from 10secs to 4min, preferably, 40 to 90secs. The treatment time in any particular case depends upon the treatment temperature. The treatment time and temperature should be sufficient as to ensure that the coating is cooked to the desired extent, but too high a temperature for too long a time will result in increased colouring of the coating of the food product, leading eventually to burning.

The super-heated steam, or hot gas and/or vapour, is advantageously blown or drawn by one or more fans onto a single layer of the fried food products. The superheated steam may be formed by blowing or drawing steam through a heat-exchanger.

When super-heated steam is used in the air/steam treatment step, that step may, for example, be carried out by passing the food products through a unit such as a "Defatter"produced by Potato Processing Machinery AB designed for use in the production of potato crisps, steam being injected into the unit and being super-heated within it. When it is desired to use hot air in the treatment step rather than super-heated steam, the same unit may be used but without injecting steam into it. Alternatively, hot air, or hot air and steam combinations, can be used in the treatment step by employing a so called"impingement oven"Advantageously, however, when using such an oven, the hot air and/or steam is directed over the food product in substantially one general direction, for example, substantially vertically downwards, rather than in opposing directions, for example, vertically upwards and downwards, as is a mode of operation of some commercially-available impingement ovens.

The batter coating on the food products may be applied in a three-coat system involving applying a first initial layer of a relatively thin batter, often referred to as"an adhesion layer", an intermediate layer of crumbs, and finally a top coat of batter, which preferably contains a leavening agent. The batter coating may comprise more than three layers, however, for example, with a fine wash and pre-dust being applied prior to the adhesion layer, but the process of the invention can also be used for food products referred to as"breaded"and having a coating of batter and an outer covering of crumbs.

The thickness of the coating material enrobing a food product can be measured in terms of the"yield"of the food product defined as the weight of the coated food product divided by the weight of the uncoated food product and expressed as a percentage. In the process of the invention, the yield of the food product after application of its coating, but before frying, is advantageously within the range of from 160 to 180%, and after frying, during which the food product generally loses water but takes up fat, is advantageously within the range of from 160 to 190%.

The fat content of the coating after the food product has been fried and before the air/steam treatment is advantageously not more than 35% by weight based on the weight of the coating, and the fat content of the coating after the air/steam treatment is advantageously not more than 28% by weight based on the weight of the coating.

The batter-coated food products may be prepared, prior to the air/steam treatment, as described and claimed in our co-pending patent specification GB 2 327 331A in which there is disclosed a process for preparing batter-coated food products, which comprises coating a food product in a batter containing leavening agent, introducing the coated food product into a fryer containing a frying medium, allowing the coated food product to come into contact with an embossing surface of submerger conveyor means, the embossing surface being so transported by the submerger conveyor means as to keep a food product in contact with it submerged in the frying medium, and the embossing surface having a pattern of recesses in it, the coating material of the food product expanding into the recesses of the embossing surface and the food product remaining in contact with and stationary relative to the embossing surface at least until the outermost surface of the coating has set sufficiently for the coating to retain an embossed pattern on removal from the embossing surface, and then allowing the coated food product to leave, or effecting removal of the coated food product from, the embossing surface.

The food products that are coated may be meat, poultry, fish (including molluscs and crustaceans) and/or vegetable food products but preferably comprise fish or chicken.

In the case of food products made of vertebrate fish, the food products may be regularlyshaped pieces of, for example, trapezoidal shape, or they may be natural fillets or of filletlike shape.

Advantageously, after the air/steam treatment, the food products are chilled or frozen and then packed.

The invention also provides apparatus for preparing coated food products which comprises means for coating a succession of food products with batter, a fryer and means for treating a succession of fried food products with super-heated steam, or hot gas and/or vapour, there also being provided means for conveying batter-coated food products from the coating means to the fryer and means for conveying fried food products from the fryer through the said treatment means. The means for treating the fried food products with super-heated steam, or hot gas and/or vapour, advantageously comprises means for causing the super-heated steam, or hot gas and/or vapour, to flow over the food products at a velocity of at least 8m/sec.

The invention further provides a batter-coated food product obtainable by the process, or by the apparatus, of the invention. The invention further provides a fried batter-coated food product having a coating having a fat content of not more than 28% by weight based on the weight of the coating.

A process and apparatus for preparing coated food products in accordance with the invention will now be described, by way of example, with reference to the accompanying drawing which is a diagrammatic plan view of apparatus for carrying out the process of the invention.

Referring to the accompanying drawing, equipment for applying a batter coating to food products in a thre. : stage process (a three-coat system) comprises an applicator I arranged to apply an adhesion layer of thin batter to a succession of food products (not shown) carried through the applicator on a conveyor 2, a breader 3 for applying a covering of crumbs to the adhesion layer, and then a second batter applicator 4 for applying a batter containing a leavening agent (which may be of a kind referred to as "tempura batter"). That equipment is arranged upstream of an inlet end 5a of a fryer 5 containing oil as frying medium. The fryer 5 is provided with one or more conveyers (not shown) for assisting the passage of the batter-coated food products through the fryer from its inlet end 5a to its exit end 5b.

Adjacent to the exit end 5b of the fryer is situated an air/steam treatment unit 6, which may be, for example, a Defatter made by Potato Processing Machinery AB. The unit 6 comprises a housing 6a through which a conveyor 7 (only the part emerging from the unit 6 is shown) is arranged to transport a single layer of the coated food products.

A fan (not shown) is provided to blow steam injected into the housing 6a through a heat exchanger (not shown), where it is super-heated to temperatures within the range of from 190 to 210 C. From the heat exchanger, the super-heated steam is directed to flow over the coated food products on the conveyor 7. A filter (not shown) is provided to remove fat from the steam after it has passed over the food products, and that fat may be recirculated to the fryer 5, if desired. If it is desired to use hot air rather than super-heated steam, as for example when it is unnecessary to carry out the air/steam treatment step in a reduced oxygen environment (such an environment generally being obtained when treating with super-heated steam in the housing 6a) because it is not required to recirculate the fat removed from the food products, then the unit 6 can be used without injecting the steam into it. Some steam may still be present, however, either arising from moisture in the air or as a result of being driven off from the food product. Alternatively, the unit 6 may be replaced by a commercially-available impingement oven, preferably operating to direct hot air and/or steam in substantially only one general direction, for example, vertically downwards, over a food product being treated.

At the exit end of the unit 6, is a freezer 8.

In operation, food products, for example, pieces of frozen fish, are placed in succession on the conveyor 2 and pass through the applicator 1, where they are coated in an adhesion layer of thin batter, the breader 3, where they receive a covering of crumbs, and the second batter applicator 4, where they receive a coating of tempura batter. The batter-coated food products then enter the fryer 5 at its inlet end 5a and are transported through oil in the fryer at a temperature within the range of from 190 to 21 0 C by means of the conveyor within the fryer. The time taken for each coated food product to travel from the inlet end 5a to the exit end Sb of the fryer is within the range of from 20 to 30 secs. At the exit end 5b, at least the outermost surface of the coating has set sufficiently for the food products to be removed from the fryer without damage or distortion of the coating. The food products are then conveyed in a single layer through the super-heated steam treatment unit 6. Super-heated steam at a temperature within the range of from 190 to 210 C is directed to flow over the coated food products at a velocity (measured in the vicinity of a food product being treated) of approximately 18m/sec by the fan. The super-heated steam acts to remove fat from the surfaces of the coated food products and to finish cooking the coating. On emerging from the treatment unit 6, after a period of approximately 60 secs travelling through the unit, the food products have a crisp coating and a lower fat content than similar coated food products produced in a conventional manner.

The food products are conveyed to the freezer 8, or alternatively to a chiller (not shown), before packing.

Instead of the batter application equipment shown in the drawing, the food products may instead pass through a batter applicator and then a breader, to give a "breaded"end product.

As an alternative to the fryer 5, a fryer as described and shown in Figs. 2-6 of our co-pending patent specification GB 2 327 331 A may be used.

The following Example illustrates the process of the invention : Shaped cod portions of approximately 76g in weight at temperatures within the range of from-10 to-18 C were coated in batter in a three-stage process using equipment as shown and described with reference to the drawing. Firstly, the cod portions passed through the applicator 1 and were coated in an adhesion batter, the dry ingredients of which had the following composition : % (w/w) Wheat Flour 47.0 Wheat Starch 29.0 Modified Starch 19.0 Salt 3.1 Pepper 2.0 Water was added to the above mixture (typically 100 parts by weight of dry ingredients to 170 parts by weight of water) to give a batter having a viscosity represented by a flow time of 20 seconds through a flow cup of a volume of approximately 106cm3 having an aperture in its base of 4. 75mm in diameter. That flow time was measured by filling the cup with the batter with the aperture closed, opening the aperture, and measuring the time taken for the batter to flow out of the cup taking the end of the flow as being the point at which there was constant flow out of the aperture. The cod portions coated in the adhesion batter had a yield of approximately 107%.

The cod portions were then passed through the breader 2 which applied crumb having the following composition : % (w/w) Breadcrumb 89.3 Flavouring 5. 0 Wheat Flour 3.0 Salt 1.4 Oil 1.3 The crumbed portions had a yield of approximately 128%. They were then passed through the second batter applicator and given a top coating of a tempura batter, the dry ingredients of which had the following composition : % (w/w) Wheat Flour 70.0 Fat 10.0 Salt 5. 0 Starch 5.0 Raising Agents 3.5 Skimmed Milk Powder 2.5 Flavouring 2.0 Dextrose 1.0 The raising agents consisted of 1.48% by weight of sodium bicarbonate and 1.65% by weight of sodium acid pyrophosphate (SAPP) and 0.37% by weight of monocalcium phosphate (MCP). Water was added to the mixture (typically 100 parts by weight of dry ingredients to 162 parts by weight of water) to obtain a batter having a viscosity represented by a flow time of 35 to 40 seconds through a flow cup having a volume of approximately 106cm3 and an aperture of 7.00mm in diameter, taking the end of the flow as being the point at which there was constant flow through the aperture as described above. The cod portions with their top coat had a yield of approximately 172%.

The cod portions were then introduced into the fryer 5 containing palm oil at a temperature of from 200 to 205 C. The residence time was 25 seconds before exiting the fryer. At that stage, the outermost surface of the coating on the food products was set sufficiently for further handling without a high risk of significant distortion or damage. The total fat content of the food products at that stage was found to be typically 13% by weight based on the weight of the food product, with the fat content of the coating calculated as being 27. 7% by weight based on the weight of the coating, and the yield of the food product was approximately 180%, the coating having lost water but taken up oil during the frying step.

The food products were then passed through the treatment unit 6 and treated with super-heated steam, with the fan speed set to direct the super-heated steam onto the food products at a velocity of approximately 18m/sec, the temperature of the super-heated steam in the region of the food products being approximately 200 C. The food products remained in the unit 6 for approximately 60 secs, and were found on exiting the unit to have a crisp, cooked coating with a fat content of approximately 8% by weight based on the weight of the food product, with the fat content of the coating calculated as 16.8% by weight based on the weight of the coating.

Claims

What we claim is:

1. A process for preparing coated food products, which comprises coating a food product in batter, frying the batter-coated food product for a length of time sufficient to set at least the outermost surface of the batter coating, and treating the battercoated food product with super-heated steam.

2. A process for preparing coated food products, which comprises coating a food product in batter, frying the batter-coated food product for a length of time sufficient to set at least the outermost surface of the batter coating, and treating the battercoated food product with hot gas and/or vapour.

3. A process as claimed in claim 2, wherein the hot gas is air.

4. A process as claimed in claim 2 or claim 3, wherein the vapour is steam.

5. A process as claimed in any one of claims 1 to 4, wherein the batter-coated food product is fried for a time within the range of from I Osecs to I min.

6. A process as claimed in claim 5, wherein the batter-coated food product is fried for a time within the range of from 20 to 30secs.

7. A process as claimed in any one of claims I to 6, wherein the batter-coated food product is fried at a frying temperature within the range of from 150 to 210 C.

8. A process as claimed in claim 7, wherein the batter-coated food product is fried at a frying temperature within the range of from 190 to 210 C.

9. A process as claimed in any one of claims I to 8, wherein the fried battercoated food product is treated with super-heated steam, or hot gas and/or vapour, at a temperature within the range of from 180 to 230 C.

10. A process as claimed in claim 9, wherein the fried batter-coated food product is treated with super-heated steam, or hot gas and/or vapour, at a temperature within the range of from 190 to 210 C.

11. A process as claimed in any one of claims 1 to 10, wherein the superheated steam, or hot gas and/or vapour, is caused to flow over the food product at a velocity of at least 8m/sec.

12. A process as claimed in any one of claims 1 to 11, wherein the superheated steam, or hot gas and/or vapour, is caused to flow over the food product at a velocity of not more than 25m/sec.

13. A process as claimed in claim 11 or claim 12, wherein the super-heated steam, or hot gas and/or vapour, is caused to flow over the food product at a velocity within the range of from 15 to 20m/sec.

14. A process as claimed in any one of claims 1 to 13, wherein the battercoated food product is treated with super-heated steam, or hot gas and/or vapour, for a period within the range of from I Osec to 4min.

15. A process as claimed in claim 14, wherein the batter-coated food product is treated with super-heated steam, or hot gas and/or vapour, for a period within the range of from 40sec to 90sec

16. A process as claimed in any one of claims 1 to 15, wherein the superheated steam, or hot gas and/or vapour, is blown or drawn by one or more fans onto a single layer of the food products.

17 A process as claimed in any one of claims 1 to 16, wherein the superheated steam is formed by blowing or drawing steam through a heat-exchanger.

18. A process as claimed in any one of claims 1 to 17, wherein the food product is coated in an adhesion layer of batter, a layer of crumbs and then a top coat of the batter.

19. A process as claimed in claim 18, wherein the top coat of batter contains a leavening agent.

20. A process as claimed in any one of claims 1 to 19, wherein the food product is coated in a layer of a batter and an outer covering of crumbs.

21. A process as claimed in any one of claims 1 to 20, wherein the yield of the food product after application of its coating, but before frying, is within the range of from 160 to 180%, and after frying is preferably within the range of from 160 to 190%.

22. A process as claimed in any one of claims 1 to 21, wherein the fat content of the coating after the food product has been fried and before the treatment with superheated steam or hot gas and/or vapour is not more than 35% by weight based on the weight of the coating.

23. A process as claimed in any one of claims 1 to 22, wherein the fat content of the coating after the food product has been treated with super-heated steam or hot gas and/or vapour is not more than 28% by weight based on the weight of the coating.

24. A process as claimed in any one of claims 1 to 23, wherein, for the frying step, the batter-coated food product is introduced into a fryer containing a frying medium, and the coated food product is allowed to come into contact with an embossing surface of submerger conveyor means, the embossing surface being so transported by the submerger conveyor means as to keep a food product in contact with it submerged in the frying medium, and the embossing surface having a pattern of recesses in it, the coating material of the food product expanding into the recesses of the embossing surface and the food product remaining in contact with and stationary relative to the embossing surface at least until the outermost surface of the coating has set sufficiently for the coating to retain an embossed patcern on removal from the embossing surface, and then the coated food product is allowed to leave, or its removal is effected from, the embossing surface.

25. A process as claimed in any one of claims 1 to 24, wherein the food product is fish or chicken.

26. A process as claimed in any one of claims 1 to 25, wherein, after treating with super-heated steam or hot gas and/or vapour, the food product is frozen, or chilled.

27. A process substantially as hereinbefore described with reference to the Example herein.

28. A process substantially as hereinbefore described with reference to the drawing.

29. Apparatus for preparing coated food products which comprises means for coating a succession of food products with batter, a fryer and means for treating a succession of fried food products with super-heated steam or hot gas and/or vapour, there also being provided means for conveying batter-coated food products from the coating means to the fryer and means for conveying fried food products from the fryer through the said treatment means.

30. Apparatus as claimed in claim 29, wherein the means for treating the fried food products with super-heated steam, or hot gas and/or vapour, comprises means for causing the super-heated steam, or hot gas and/or vapour, to flow over the food products at a velocity of at least 8m/sec.

31. Apparatus as claimed in claim 29 or claim 30 for carrying out the process as claimed in any one of claims 1 to 28 herein.

32. Apparatus substantially as hereinbefore described with reference to, and as shown in, the drawing.

33. A batter-coated food product obtainable by a process as claimed in any one of claims 1 to 28

34. A fried batter-coated food product having a coating having a fat content of not more than 28% by weight based on the weight of the coating.