GB1570573A - Process for preparing a laminated food product - Google Patents

Abstract

The product is composed of a multitude of superposed coherent films welded together at least partially and composed of agglutinated fragments of fruits, vegetables and/or cereals. Such a product, particularly based on potatoes, lends itself to the preparation of rissoles or lasagnas.

Description

(54) A PROCESS FOR PREPARING A LAMINATED FOOD PRODUCT (71) We, SOCIETE DES PRODUITS NESTLE S.A., a Swiss Body Corporate of Vevey, Switzerland; do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a process for preparing a food product of laminated texture consisting of a plurality of coherent films arranged one above the other and welded at least partly to one another, and to food products when produced by this process.

In one known process for producing a beef, chicken or fish meat analog, an aqueous solution or dispersion of vegetable protein containing up to 40% by weight, of oil, based on dry matter, is prepared and converted into a coherent film by drying it on a drum, several layers of the film removed from the drum are stacked one on top of the other and the entire stack obtained is rehydrated, after which the stack is dried and rehydrated again once or several times to provide it with good resistance to chewing. Accordingly, this process makes use of the properties of cohesion and adherence of materials rich in proteins to make a meat analog of laminated structure which, when chewed, creates an impression similar to that felt when chewing a piece of beef, chicken or fish meat.

It is also known that sheets of vegetable material can be produced by a process in which fruits, vegetables or vegetable debris are ground in the presence of water, the suspension obtained is subjected to the enzymatic action of a mixture of cellulase and pectinase, the paste obtained is applied to a flat surface and then dried in hot air. This process utilises the filmogenic properties of oligosaccharides resulting from the degradation of the hemicelluloses and pectin contained in the vegetable material used. The use of vegetable materials of high starch content, particularly potatoes, is not recommended in this process because in their case it is difficult to obtain a continuous sheet.

There are also various other processes for producing food products based on fruits or vegetables in the form of sheets or sheet fragments. In one of these processes, an aqueous dispersion is formed from a vegetable material, such as a flour of potatoes and rice or even an apple or banana puree, the aqueous dispersion thus formed is foamed, the resulting foam is dried on a drying belt or even on a drum, the sheet obtained, which is still. flexible, is cut into pieces which are fried to make crisps or chips. In another process, dried preserved foods are produced by rolling and drying a concentrated puree of fruits or vegetables. In yet another process, cereals, vegetables or fodder plants are ground up, after which water, binders and plasticisers are added to give a viscous mass which is dried on a steel belt. The product obtained in this way is in the form of a continuous sheet which has sufficient elasticity and tensile strength to be used as an edible wrapping paper, for example for food rations. Accordingly, processes of this type are aimed at producing end products in the form of sheet fragments or continuous, coherent and relatively resistant sheets.

In another known process for producing a product of the crisp or chip type, dehydrated cooked potatoes, i.e. potato flakes or granules, are mixed with a pulp of raw potatoes or of a vegetable, such as onions, or of a fruit, such as apples, the resulting mixture is rolled to form a sheet and the sheet or two superposed sheets are cut into pieces which are then fried. The superposed pieces give products resembling mashed potatoes. They are simply crisps or chips slightly thicker than normal and similar in structure to the crisps or chips obtained by cutting a single sheet.

Finally, it is known that flakes or vegetable material can be produced by processes in which a pulp of this material, for example a potato pulp, is prepared and dried on rollers, the film formed on a roller is separated therefrom and broken up into small pieces or flakes. This type of film is friable and readily disintegrates into flakes.

The present invention provides a process for producing a food product of laminated texture comprising a plurality of coherent films arranged one above the other and welded at least partly to one another, the films consisting for the most part at least of agglutinated fragments of one or more fruits, vegetables, and/or cereals, said process comprising preparing an aqueous dispersion or paste of one or more fruits, vegetables and/or cereals, formibg the dispersion into a layer on a heated surface, drying the layer on the surface in such a way that a coherent film is produced, removing the film from the heated surface, moistening the film and producing a stack of superposed layers of the moistened film whilst at the same time compressing superposed layers.

The present invention also relates to food products when produced by this process.

These products have particular qualities and can thus lend themselves to original applications.

Contrary to any prediction which might have been made on the basis of the prior art, it was found that it was possible to make a structured product by stacking films of vegetables poor in protein and rich in starch or cellulose. It might have been assumed that the individual films would be too friable to be handled. In fact, it has been found that it is possible to grind up vegetables of all kinds, such as potatoes, tomatoes, carrots or onions, and fruits of all kinds, such as apples or bananas for example, with a view to forming an aqueous dispersion or paste and drying the aqueous dispersion or paste thus formed, for example on a drum, optionally after the addition as required of a cereal flour, such as cornflour or wheatflour for example, to obtain a coherent film which can be removed from the drum, handled without breaking, moistened and, for example, wound onto a cylinder parallel to the roller, and that it is possible in this way to obtain a stack of superposed layers of films which adhere sufficiently to one another to form a structured product which does not disintegrate and which lends itself to all kinds of preparations and interesting and original applications.

In the interests of simplicity, this product will be referred to hereinafter as a "laminate", on the understanding that, in the context of the invention, a laminate is a product of laminated texture consisting of a plurality of coherent films arranged one on top of the other and welded at least partly to one another, the films consisting of agglutinated fragments of edible material. Thus, it will be possible to speak in terms of a laminate of vegetables, fruits and/or cereals without any danger of confusion with the confectionery speciality known as flaky pastry to which the product according to the invention bears only little similarity both in composition and also appearance. In the expression "agglutinated fragments" of edible material, such as vegetables, fruits and/or cereals, the word "fragment" is used in a broad sense and covers the corpuscles or particles of all sizes resulting from the crushing or grinding of the materials in question.

One preferred embodiment of the product according to the invention is a potato laminate. Another embodiment is a laminate of potatoes or cereals and fruits or vegetables, the cereals preferably being corn (maize) or wheat, the vegetables preferably being tomatoes, carrots, spinach, peas or onions, and the fruits preferably being apples or bananas. It has been found that a potato laminate according to the invention is eminently suitable for the preparation of a large number of combined dishes which are inspired by known specialities, such as lasagnes or pizzas for example, or which are entirely new, such as for example meat rolls wrapped in potato or a "gratin" of fish on a bed of potatoes. The potato laminate has a sufficiently stable structure to be used for applications which would have been unthinkable with potato flakes, granules or fragments. For applications, such as these, potato may with advantage be combined with tomato or with a green vegetable, such as peas or spinach for example.

It is possible to imagine all kinds of laminates containing potatoes, other vegetables, fruits and/or cereals in various respective proportions, and to envisage all kinds of new recipes which are attractive and interesting from the point of view of industrial confection, for example in the form of deep-frozen products. Thus, a laminate of tomatoes and potatoes or of peas and wheatflour or even of carrots, cornflour and wheatfiour, lends itself to the confection of complete dishes, such as the combination of a slice of meat or fish and a piece of laminate of the same dimensions, the whole being coated with a pancake batter and breadcrumbs and then fried in oil, or the combination of a casing of laminate and a filling of meat, egg or cheese, the whole being sauteed in a frying pan for example.

So far as laminates containing a large proportion of fruit, for example half fruit/half wheatflour, by weight of dry material are concerned, it has been found that they have a very close texture and that when chewed, they can create an impression similar to that created by a slice of dried fruit. This opens up the possibility of preparing dried-fruit analogs in large quantities, rapidly, without the least waste and hence at greatly reduced cost.

The starting material used for carrying out the present process may be selected from fresh vegetables, either raw or cooked, cleaned and pared or preserved by drying, canning or deep freezing, fresh fruits which have been cleaned and pared or preserved by canning or deep freezing, ground or flaked cereals, cooked or dried potatoes, for example in the form of flakes or granules. This starting material may then be worked to form an aqueous paste or dispersion containing approximately 8 to 40% by weight of dry matter. To this end, it is possible, in the case of whole or coarsely divided fruits, to crush them as such or, if necessary, with addition of water. In the case of fragments of dried vegetables, they may be rehydrated and then crushed. In the case of potato granules or flakes, it is possible simply to add water to them while mixing. In cases where it is intended to produce a single laminate with different starting material, these starting materials may be mixed at the outset or during crushing or reconstitution or even after having separately prepared an aqueous dispersion or paste from each of them.

Colouring matter, vegetable fibres, binders, plasticisers, aromas, aroma precursors, aroma strengtheners and other standard edible additives may also be added to the aqueous dispersion or paste to provide the product with particular nutritive, gustative, keeping or cohesion properties.

One heated surface which has proved to be particularly suitable for carrying out the process according to the invention is that of a drying roll. The number of rolls, their dimensions, the width of the gap between two adjacent rolls, the speed of rotation of the rolls and the temperature of their surfaces may all be varied within wide limits. For example, it is possible to use a two-roll dryer in which the directions of rotation of the two rolls converge from above towards the gap separating them, or a dryer comprising a main roll of large diameter with several satellite rolls of smaller diameter distributed around its periphery. In cases where dryers such as these are used, it is possible to heat the two rolls or the main roll to a temperature of from about 120 to 160"C, to feed the rolls manually or mechanically, to fix the width of the gap between the rolls within the usual limits for this type of apparatus and to rotate the rolls at such a speed that the drying time amounts to between about 2 and 25 seconds.

The coherent film formed by the aqueous dispersion or paste dried on the heated surface may be removed therefrom by means of a scraper which closely follows the surface in question. The film may be separated from a drying roller for example by applying a straight-edge scraper to its surface at a certain angle parallel to its axis. The separated film may have- a residual moisture content of the order of 3 to 307o by weight.

The separated film may be moistened for example by spraying water onto it from above or by passing it through a flow of steam. The film may be moistened in such a way that it has a moisture content of from 10 to 90% by weight. It is possible for example to stack separate leaves of the film or to wind several layers of a continuous ribbon of the film onto a support. In cases where a roller dryer is used, the separated film may be collected and wound onto a rotating cylinder arranged parallel to the roller. In this case, the film may be moistened during its travel between, the drying roller and the cylinder or during its winding. In cases where it is intended to spray water onto the film being wound, it is of advantage to use for this purpose one or more flat-jet or round-jet nozzles so that the film is uniformly moistened over its entire width. Water having a temperature of from 5 to 90"C is preferably used for moistening the film. Colorants, aromas, aroma precursors, aroma strengtheners and other standard edible additives may be added to the water used for moistening in order to provide the product with particular nutritive, gustative, or keeping properties.

The superposed layers of film may be compressed by applying a pressure to the stack.

In the case of winding, a pressure may be applied to the stack during its formation by means of a roll arranged parallel to the wind ing cylinder, The stack may be heated during its formation with a view to improving its texture by increasing the cohesion of the films with one another. In the case of winding, unless heating has already been effected by the steam moistening process for example, it is possible for this purpose to arrange a heating element operating by convection or radiation at a suitable distance from the winding cylinder.

The stacking or winding process is preferably continued until the compressed superposed layers have a total thickness of from about 0.1 to 10 cm. In the case of winding, the laminate obtained may be separated by cutting it along a generatrix of the cylinder and then spreading it flat.

As mentioned above, although the product produced by the process according to the invention may be consumed as such after having been prepared in all kinds of ways, such as in a deep fryer or in a microwave oven, for example as an appetiser or snack, in a frying pan or in water, for example in a soup, it is preferred to use it in the fresh state or after preservation by dehydration, deep freezing or canning, in the preparation of original complete or dietetic culinary products in the category of, for example, vol-auvents, canapes, gratins, rolls and other rissoles.

The following Examples are intended to illustrate the process according to the present invention for producing food products, the products prepared by this process, and their applications. The percentages quoted represent percent by weight.

EXAMPLE 1 Potatoes of the Bintje variety are cleaned, pared and cooked. They are reduced into an aqueous puree or dispersion containing 20% of dry matter.

This dispersion is dried on a GOUDA dryer with a main roller 50 cm long and 50 cm in diameter equipped with 4 satellite rollers 13 cm in diameter. The pressure of the steam used for heating in the main roller is adjusted to 3 atms gauge, the gap between the rollers to 50 mm and the rotational speed of the main roller to 4.3 revolutions per minute. A dry film almost 50 cm in width is obtained.

The dry film is wound continuously around a 40 cm diameter cylinder driven by a variable speed motor. The speed of rotation of the cylinder is adjusted in such a way that the film is not stretched.

Water is sprayed onto the film during its travel between the dryer and the winding cylinder by means of two circular-jet nozzles aligned parallel to the winding cylinder and fed under such a pressure that, together, they spray out 14 litres of water per minute. At the same time, a flow of steam is directed onto the film from a tube drilled with small holes and arranged under the film between the dryer and the winding cylinder. The jets issuing from the pipe are redistributed into a flat, relatively homogeneous stream by means of a grid positioned immediately above the pipe. The output of steam is adjus ted to 40 kg/minute.

The stack is compressed during its forma tion by applying a slight pressure to it by means of a plastic-coated metal roller 12 cm diameter arranged parallel to and above the winding cylinder. The stack is heated during its formation by means of a linear infra-red heating element arranged parallel to the cylinder approximately 10 cm therefrom on the side opposite that facing the dryer. The heating element has an output of 6000 W.

The puree is manually distributed over the dryer and the process is continued for 1 hour.

The laminate is separated from the cylinder by cutting it along a generatrix of the cylinder.

It has a uniform, compact laminated texture slightly reminiscent of shortbread, is very light, almost white in colour and has a natural potato taste. It has a dry matter content of 40% and a thickness of approximately 1 cm. It is deep frozen for keeping.

EXAMPLES 2 to 16 A whole series of laminates is produced in the same way as described in Example 1 from various starting materials selected from fruits, vegetables and cereals and also mixtures thereof. Mechanical mixing is generally sufficient for preparing the aqueous suspension or paste, i.e. the puree. In some cases, however, a colloid mill is used for refining the puree. For each production, a basin containing approximately 50 kg of puree is prepared.

Depending upon the fluidity of the puree, it is distributed over the dryer by means of a pump or by hand. Each production lasts between 30 minutes and 2 hours. Sometimes 3 and sometimes all 4 of the satellite rollers of the dryer are brought into operation.

Moistening is carried out with water or steam or both. Infrared heating is occasionally used when it is found that it really improves the cohesion of the films in the stack. The following Table sets out in detail the starting materials used, the main working conditions and the results obtained: Puree Dryer, main roller Moistening Laminate Starting material, Dry steam Dry preparation (pro- matter pressure matter Ex. portions in % of content atoms water steam content No. dry matter) % rpm gauge l/min kg/min % colour texture taste 1 puree of fresh, 20 4.3 3 10 40 40 white compact, potatoes cooked potatoes like shortbread 2 43% of yellow pea 20 4.3 3 10 - 46 cream compact, potatoes fluor mixed with like 57% of fresh shortbread cooked potatoes 3 yellow pea flour+ 38 8.5 2 16 20 51 caramel crisp slightly of water, homogenised peas 4 green pea fluor+ 25 8.5 2 16 - 59 green gum-like peas water, homogenised 5 50% of banana 31 4.3 4 14 - 38 grey dense very dried mixed with 50% gummy banana of wheatfluor and homogenised 6 62% of tomato 30 4.3 5 10 - 33 red close tomato concentrate mixed with 38% of potato granules 7 45% of wheatflour 33 4.5 4.5 - 40 38 beige dense dried mixed with 55% of leathery potato potato puree and then homogenised 8 50% of potato 25 1.8 5 10 - 40 yellow dense potato puree mixed with 50% of fresh cooked potatoes and homogenised 9 14% of freeze- 25 4.3 3 10 - 38 cream compact, roast dried onion powder friable onion mixed with 86% of fresh cooked potatoes Puree Dryer, main roller Moistening Laminate Starting material, Dry steam Dry preparation pro- matter pressure matter Ex. portions in % of content atoms water steam content No. dry matter) % rpm gauge l/min kg/min % colour texture taste 10 50% of freeze- 24 3.3 4.5 14 - 45 orange close, slightly of dried carrot pow- gummy carrots der mixed with 50% of wheatfluor +water 11 90% of fresh 26 3 3 12 40 42 white felt-like, potatoes cooked potatoes friable mixed with 10% of potato fibres 12 50% of soya flakes 33 5 3.5 12 40 45 yellow crisp flavourless mixed with 50% of bread cornflour+water and then homogenised 13 20% of soya flakes 20 4.3 3 10 20 35 cream compact, potatoes mixed with 80% like of fresh cooked shortbread potatoes 14 50% of deep 29 4.3 3 10 - 39 green watery peas frozen green peas mixed with 50% of wheatflour and homogenised 15 66% of ground 30 4 4 10 - 40 orange close carrots deep frozen carrots+17% of cornflour+17% of wheatflour, mixed 16 70% of deep fro- 35 5 3 12 - 32 green loose spinach zen spinach concentrate mixed with 30% of wheatfluor For preserving the laminations of this series of Examples 1 to 16, they are individually packed in plastic wrappers quickly deepfrozen and stored at --20"C.

EXAMPLE 17 2 to 3 mm thick layers are separated from the thawed potato laminate of-Example 1, cut into pieces measuring approximately 3 X3 cm and cooked in a microwave oven. Crispy pleasant-tasting appetisers are obtained.

EXAMPLE 18 A cod fillet is covered with an equally thick layer of laminate. The whole is coated in pancake batter and breadcrumbs, fried in oil and deep-frozen Before eating, it is briefly sauteed in margarine in a frying pan. Four fillets each covered by a piece of different laminate, namely the thawed laminates of Examples 6 (tomatoes and potatoes), 11 (potatoes and fibres), 14 (green peas and wheatflour) and 15 (carrots and wheat and cornflour) are prepared in this way. The laminates form an extremely pleasant combination with the fish and give products with attractive textures and tastes.

EXAMPLE 19 A dish of the lasagne type is prepared from successive layers of bechamel sauce, thawed potato laminate of Example 1, meat filling, potato laminate, meat filling, potato lamin ate and bechamel sauce. (A second dish is prepared in the same way, except that the meat filling is replaced by a mushroom filling.

The two products are deep-frozen. Before eat ing, they are oven-heated for 30 to 40 minutes at 2240C. The structure of the two products has remained intact, above all the structure of the product containing mush rooms. There is thus obtained a tasty potato dish which it would be impossible to prepare from potato flakes, potato granules or fragments of fresh tubers, because the structure would collapse as a result of the diffusion of the sauce of the filling through the layers of potato.

EXAMPLE 20 A 2 mm thick layer is removed from the thawed potato laminate of Example 1. A circle is cut out of this layer and folced in the form of a half moon. The half moon thus formed is then filled with a raw egg and finely chopped spices and vegetables. The edges are then pinched together to close the patty thus formed. The patty is fried in oil and then deep frozen. Before eating, it is reheated in an oven. It is crisp and its filling goes very well with the potato taste of its crust.

EXAMPLE 21 A piece of the thawed laminate of Example 11 is covered with a layer of meat sauce and then deep frozen. Before eating is type of canape, it is reheated in an oven. Although very simple, this product is nevertheless attractive.

EXAMPLE 22 During the preparffion of a pizza covered with low fat cheese and mushrooms, the normal base of flour-based crust is replaced by a disc of the thawed laminate of Example 11. A very suitable product with a certain interest from the dietetic point of view is obtained.

EXAMPLE 23 A filling is prepared from rninced beef, chopped onions and spices. It is formed into rolls which are wrapped in a thin layer of the thawed laminate of Example 11 and the defrozen. Before these rolls are eaten, they are sauteed in margarine in a frying pan. The sauteed rolls have a crisp casing, a juicy interior, a splendid taste and a really very appetising general appearance EXAMPLE 24 A cod fillet is covered with a layer of cheese, placed on a piece of the thawed laminate of Example 1 and deep frozen. Before it is eaten, this fish gratin is reheated in an oven. The laminate puffs out in the oven and gives the gratin an attractive appearance and texture.

Claims (14)

WHAT WE CLAIM IS

1. A process for producing a food product of laminated texture comprising a plurality of coherent films arranged one above the other and welded at least partly to one another, the films consisting for the most part at least of agglutinated fragments of one or more fruits, vegetables and/or cereals, said process comprising preparing an aqueous dispersion or paste of one or more fruits, vegetables and/or cereals, forming the dispersion into a layer on a heated surface, drying the layer on the surface in such a way that a coherent film is produced, removing the film from the heated surface, moistening the film and producing a stack of superposed layers of the moistened film whilst at the same time compressing the superposed layers.

2. A process as claimed in claim 1, wherein the aqueous dispersion or paste has a dry matter content of from 8 to 40% by weight.

3. A process as claimed in claim 1 or 2, wherein the film is moistened in such a way that its water content amounts to between 10 and 90% by weight.

4. A process as claimed in any of claims 1 to 3, wherein the aqueous dispersion or paste is dried on a roller dryer and the film is separated from a roller by means of a scraper applied to the roller.

5. A process as claimed in claim 4, wherein the separated film is wound into a rotating cylinder arranged parallel to the roll.

6. A process as claimed in claim 5, wherein the separated film is moistened by spraying it with water or by directing a jet of steam onto it before or during its winding.

7. A process as claimed in any of claims 1 to 6, wherein the stack is compressed during its formation by applying a slight pressure to it by means of a roller arranged parallel to the winding cylinder.

8. A process as claimed in any of claims 1 to 7, wherein the stack formed is dried or deep frozen.

9. A process for producing a food product of laminated texture substantially as described with particular reference to any of the Examples.

10. A food product when produced by a process as claimed in any of claims 1 to 9.

11. A product as claimed in claim 10, wherein the films are composed of potato fragments.

12. A product as claimed in claim 10, wherein the films are composed of fragments of potatoes or cereals and fruits or vegetables.

13. A product as claimed in claim 12, wherein the cereals are corn maize or wheat, the vegetables are tomatoes, carrots, spinach, peas or onions and the fruits are apples or bananas.

14. A food product of laminated texture substantially as described with particular reference to any of the Examples.