GB2058539A - Simulated food products and method of manufacturing therefor - Google Patents

Abstract

Simulated food products in the form of discrete shape-retaining pieces having a calcium alginate gel matrix, and in particular simulated meat petfoods, are made from a mixture produced by mixing (a) an aqueous slurry comprising a comminuted food material and having a water-soluble alginate salt dissolved therein, with (b) a slurry, usually aqueous, of a calcium salt sparingly soluble in water having a monohydric or polyhydric alcohol or a sugar comprised therein as a retardant; and thereafter allowing the mixture to gel. The alcohol may be isopropyl alcohol, glycerol, propylene glycol or butylene glycol. Corn syrup, sucrose or a mixture of sugars may be used as the sugar. The comminated food may be meat, fish or offal, or fruit or vegetable material.

Description

SPECIFICATION Simulated food products and method of manufac ture therefor This invention relates to a food product for consumption by humans or domestic pet animals, and to a method for its manufacture.

In particular, it relates to the production of simulated meats, fish, fruits or vegetables in the form of discrete shaped pieces for use in canned or frozen meat products, petfoods, jams, confections or desserts. It is also to be understood that the product of this invention has many other possible uses and its use is not restricted to such products as previously mentioned, nor to its sale in a canned or frozen form.

Over the years, numerous attempts have been made to produce shape-retaining simulated food products having a matrix composed of gelled calcium alginate or other divalent metal alginate. One aspect of this technique is to make possible the reformation of meat-like pieces from meat wastes which have been comminuted. In general, two alternative approaches have been adopted.

In the first approach, a mix is so formed into subdivided units and each is provided with a skin. This is typified by UK Patent Specification 1 474 629, in which an aqueous mixture containing finely-divided food material e.g. meat and a soluble alginate salt is formed into pieces to simulate meat. These pieces are then treated with a solution containing calcium ions. This forms a gelled calcium alginate skin around each piece to encapsulate it and help retain its shape.

A variation of this method, also described in UK Patent Specification 1 474 629, involves the incorpora tion of a water-insoluble calcium salt into the alginate-containing meat mix. When this mixture is surface-treated with edible acid it releases calcium at the surface and again forms a skin around the product.

In practice the methods described in 1 474629 result in the production of simulated meat pieces having a soft and sticky interior. Moreover, the food pieces so obtained are rounded in shape. They do not closely resemble cut pieces of meat or offal. Also, to get encapsulate pieces of sufficient strength to withstand subsequent processing and handling, long contact times between the calcium salt solution and the original pieces are required. Such long contact times are not well suited to continuous industrial processing.

Another related method of making shaperetaining pieces of foodstuff is described in UK Patent Specifications 1 484563 and 1 302 275. In this, a soluble calcium salt is mixed with a food product such as fruit pulp. Drops of the mixture are then contacted with a water-soluble alginate solution so as to produce artifical fruits with a pulpy centre and a gel skin. However, the problems of long contact time previously mentioned are not overcome.

In the second approach to the manufacture of simulated food products based on an alginate gel matrix all of the components are mixed together to provide subdivided units gel led throughout their thickness. Typically, both a source of calcium ions and a water-soluble derivative of alginic acid are mixed with a comminuted food material. This is generally carried out in the presence of a retarding agent, in order to prevent instantaneous reaction between the calcium and the alginate.

Many "instant" pudding mixes are of this type, but a more pertinent example ofthis second approach for the purposes of the present invention is afforded by UK Patent Specification 1 302432. In this there is described the manufacture of a simulated adipose tissue, by reacting together (a) an aqueous solution of an alkali metal salt of alginic acid and (b) an alkaline earth metal salt in the presence of fat and a retarding agent.

Substances typically described in the literature for use as retarding agents in this second approach are salts of phosphoric acids, ethylenediamine tetra acetic acid, or salts of citric acid.

Known retarding agents, however, often lead to the production of gels of unsuitable quality, or provide long and/or variable gelation times. They may also introduce into the food an adverse flavour depending upon the retardation agent employed.

The invention sets out to provide a suitable and continuous industrial method for the manufacture of simulated food products based on an alginate gel matrix. Initially, "rapid mixing" of sparingly-soluble calcium salts alone, into an alginate containing, aqueous, homogeneous food slurry was investigated. Although some success can be obtained in making simulated foods gelled with calcium alginate in this way, gelation generally occurs in inconveniently short times for continuous industrial production and an improved method for prolonging the gelation time is desirable.

It has now been descovered according to the invention that firm cutable foods may be formed using a sugar or a polyhydric or monohydric alcohol or combination thereof as retarding agents, as defined below. Such retarding agents used according to the method of the invention give a useful interval for working the food mass before setting occurs. Also the time after which the system sets to a cutable alginate gel matrix is relatively constant for a given food mixture; thus the system lends itself to continuous industrial production.

The invention accordingly consists in a method of forming a food product in the form of shaperetaining pieces which comprises the essential steps of: (a) producing an aqueous slurry of comminuted food material having a water-soluble alginate salt dissolved therein, (b) producing a slurry of a sparingly water-soluble calcium salt, the slurry additionally comprising, as a retarding agent, a sugar or monohydric or polyhydric alcohol, (c) mixing the two slurries together, (d) allowing the mixture to gel.

The invention involves along with the sparingly water-soluble calcium salt the combination of two further features, neither of which is conventional in this art, namely the use as a retarding agent of a class of substances not hitherto selected forthis purpose; and the use of a method in which two slurries are mixed, the calcium salt and retardant being present in the same slurry prior to such mixing.

The Applicants do not intend to be iimited by any theory regarding the mode of operation of the method of the invention as described above. However, it appears possible that, from the chemical point of view the sugar or alcohol weakly complexes the calcium ions arriving in the aqueous mixed slurries from the sparingly soluble calcium salt and so reduces the rate of reaction with the water-soluble alginate salt. From a manipulative point of view it appears that, during the mixing period of the two slurries any transient local overconcentrations of calcium salt are necessarily matched by suitable transient local concentrations of retarding, since both are incorporated as a slurried mixture and partake of the same distribution of short-term inhomogeneities during the brief period before mixing is complete.Whatever the reasons, however an acceptable uniform and reproducible product can be obtained on a continuous basis. On the other hand, without the use of a retarding agent, the reaction between the calcium ions arriving in solution, and the sodium alginate is very rapid and the progress of gelation is accompanied by a rise in the viscosity of the mixture (as measured by the electric current taken by a mixer mixing the mass). This gel that forms is broken up during the further mixing required to achieve a homogeneous end product and the finished mix forms a weakly structured or unstructured product.

With the appropriate quantity of retarding agent present and using the method described above, mixing to homogeneity results, with no loss of the gelling properties of the finished mixture.

In the above definition of the invention, the term "sugar" is intended to cover any mono-, di- higher oligosaccharide based on furanose and/or pyranose ring systems. In practice sucrose, glucose and fructose are preferred, although maltose and lactose are possible. It is additionally intended to cover such materials not only in chemically pure form but also in the standard grades of available materials e.g. the various types of sucrose. In particular, the invention lends itself to the use of liquid sugar materials, such as the glucose syrups made by hydrolysis of cereal grains. Mixtures of sugars may also be used.

The term "monohydric or polyhydric alcohol" is intended to cover any organoleptically acceptable organic hydroxy-compound of a predominantly alcoholic function, e.g. straight or branched chain mono-alkanols, such as ethanol, isopropanol, diols such as propylene or butylene glycol or trios such as glycerol. When polyhydric they can be of mixed type e.g. with primary and secondary -OH groups such as glycerol. They should be suitably compatible with water, since they must be mixed into the aqueous slurry of comminuted foodstuff. Although usually based on straight or branched alkyl chains, they can also be carbocyclic, alicyclic, heterocyclic, or aromatic provided that they are otherwise acceptable in the foodstuff.They can either be associated with a proportion of water, or be used as waterfree liquids, to provide the liquid phase for the slurry of calcium salt.

The above retarding agents, especially the sugars, do not give an adverse tasteto the food.

A suitable retardant vehicle for the calcium salt; slurry is an aqueous solution e.g. a solution contains ing at least 50% of the retardant. Usually, the calcium salt slurry will be used in amounts less than that of the comminuted product slurry, e.g. from 1 to 50 /O preferably 2-10% by volume.

Generally, the water soluble alginate derivative will be present in the mixture, to give an amount of 0.3 to 5% by weight of alginate in the final product.

The preferred water soluble alginate is sodium alginate. Calcium sulphate is the preferred sparingly soluble calcium salt and its preferred proportion is at least 0.5% by weight in the finished product.

It will be appreciated that a "comminuted" foods tuff can be present in any acceptable degree of subdivision, since the alginate gel provides the essential structure. Chopped or sliced meats or vegetables, chipped, grated or minced foodstuffs, mashed, pureed or puiped products can all be utilised, optionally together with flavouring materials whether solid or liquid.

Thus, in principle most food products in commi nuted form may be used in the mixture. For simu lated meat chunks a proteinaceous material may be used and fat addition may be made. The proteinace ous material used to prepare simulated meats for use in petfoods is usually ground offal on account of its low cost. Simulated fruit products may be pro duced by employing fruit pulp or even a completely artificial fruit flavoured material.

Preferred mixing equipment comprises an impel ler pump capable of being driven at high speed e.g.

(3000 revolutions per minute) which has been mod ified to act as a stirrerforthe mixture pumped there through by another pump. By using such equipment short mixing times may be achieved in a continuous system.

The homogeneous mixture (comminuted food, alginate, calcium salt and sugar or alcohol retarding agent) pumped out of this mixer can be discharged onto a conveyor or cast in moulds. It subsequently sets to a firm gelled mass: depending on the particu lar composition, gelation may be substantially com plete within a time of a few seconds up to five minutes.

The food product may be cast into the desired final shape before gelling is completed or the gelled food product may be cut into the required shape after a suitable proportion of gelling has taken place, i.e.

after partial or complete gelation.

In continuous production this is conveniently effected by allowing the material to flow on to a con veyor belt where it spreads out and gels as a flat strip which is then passed to e.g. a dicing machine.

This mode of operation can be elaborated to pro vide a further feature of the invention, in which a plurality of supplies of mixed slurries as above, prior to gelation, are fed successively on to the same mov ing conveyor belt, at locations spaced so that each layer has gelled before the next supply of mixed slurries is fed, whereby a multilayer deposit of gel led material is produced, optionally of different compositions in each layer.

We have found surprisingly that the gelled layers do not mutually adhere, so that passage through the same dicing machine as described above produces separate dice of gelled product and optionally in any desired proportion of different products diced. Thus, a high level of product ion can be obtained from a single conveyor installation.

The re-formed simulated food pieces thus obtained which comprised a uniformly distributed calcium alginate gel matrix are stable to normal industrial freezing and canning processes and may be sold in such form with or without admixture with other food materials.

A particular advantage of the process is that it may be carried out at room temperature without the need for expensive heating apparatus.

The invention is illustrated in the following examples, which are given only by way of exemplification and are not to be considered as limiting. All the percentages shown are on a weight basis.

EXAMPLE 1 A mixture of meat offals and by-products containing Beef Trimmings 20% Wet Greaves 20% Chicken Intestines 10% Fresh Whole Blood 10% Ground Bone 10% Liver 10% Beef Gullets 10% Cooked Chicken Residue 10% was finely ground through a 3 m.m. plate.

This mixture was taken at approximately 20"C and mixed with a solution of sodium alginate (Manugel GHB-Alginate Ind. Ltd) to give a slurry having the composition: Ground Meat Mixture 55% (as above) Sodium Alginate 1.5% Water 43.5% A suspension of calcium sulphate (superfine grade) in a sugar solution having the following composition was then made: Calcium Sulphate 12% Sucrose 43% GuarGum 0.80/c Liquid Caramel Erythrosine 0.01% Water 43.2% The meat/alginate mixture, 95%, was then mixed very rapidly with 5% of the calcium sulphate suspension at 20"C. After mixing for 3 seconds, the mixture was discharged onto a belt conveyor where it set to a solid mass after one minute. The set material was cut into meat-like pieces after a further two minutes.

EXAMPLE2 The method of Example 1 was performed except that the meat mixture was replaced by apple pulp.

The material set to a firm mass 20 seconds after the final mixing and discharge onto the belt conveyor.

EXAMPLE 3 Wet greaves (the residue after rendering of fat from fatty tissues) and meat meal were finely ground and the ground material mixed with an alginate solution to give a slurry of the following composition: Meat Meal 5% Ground Wet Greaves 45% Sodium Alginate 1.5% Water 48.5% A suspension of calcium sulphate in a sugar solution was made as follows: Calcium 12% Sucrose 44% Water 44% 95% of the greaves / alginatel meat meal slurry was then rapidly mixed with 5% of the calcium sul- phate/sugar suspension. After exit from the mixer, the mixed material set to a firm gel in 1 minute. The gel was then cut into pieces.

EXAMPLE4 The method of Example 3 was followed except that the wet greaves was replaced by an equipart mixture of ground peas, carrots and potato.

EXAMPLE 5 The method of Example 1 was followed except that the mixture of meat offals and by product was replaced by minced fish offals.

The simulated meat, fish, fruit or vegetable pieces, or moulded shapes, made in accordance with the Examples given were canned and heat processed, or frozen, without disintegrating.

The canned or frozen products were fed to and accepted, as appropriate by pets or humans.

It will be appreciated that variations may be made to the specific preferred features described above without departing from the broad teaching of this invention. Such variations are intended to be within the scope of this invention.

Claims (21)

1. A method of forming a food product in the form of shape-retaining pieces which comprises the essential steps of: (a) producing an aqueous slurry of comminuted food material having a water-soluble alginate salt dissolved therein, (b) producing a slurry of a sparingly water-soluble calcium salt, the slurry additionally comprising as a retarding agent a sugar or a monohydric or polyhydric alcohol, (c) mixing the two slurries together, (d) allowing the mixture to gel.

2. A method according to claim 1, wherein the slurry of calcium salt comprises a mixture of sugars.

3. A method according to claim 1, wherein the slurry of calcium salt comprises a glucose syrup as the sugar content.

4. A method according to claim 1, wherein the monohydric alcohol is isopropyl alcohol.

5. A method according to claim 1, wherein the polyhydric alcohol is selected from glycerol, propylene glycol and butylene glycol.

6. A method according to any one preceding claim, wherein after gel formation is complete or nearly complete, the gel is cut into pieces.

7. A method according to any one preceding claim, wherein the concentration of the watersoluble alginate salt in the aqueous slurry is such that in the finished food an amount of 0.3% to 5.0 /O by weight of the alginate is present.

8. A method according to any one preceding claim, wherein the water-soluble alginate is sodium alginate.

9. A method according to any one preceding claim, wherein the calcium salt is calcium sulphate.

10. A method according to any one preceding claim, wherein the sparingly water-soluble calcium salt slurry is an aqueous slurry in which the liquid medium contains at least 50% by weight of the sugar or alcohol.

11. A method according to any one preceding claim, wherein the slurry of sparingly water-soluble calcium salt has as its liquid phase a monohydric or polyhydric alcohol, which is liquid at room temperature and contains no water.

12. A method according to any one preceding claim, wherein the food material is a proteinaceous material.

13. A method according to any one preceding claim, wherein mixing together of the two slurries is completed within 30 seconds.

14. A method as claimed in any one preceding claim in which subsequently to mixing and prior to gelation the mixed slurries are allowed to flow on to a moving conveyor or belt in which they spread and gel in the form of a flat strip prior to being cut into pieces.

15. A method as claimed in claim 14 in which a plurality of such supplies of mixed slurries are fed successively on to the same moving conveyor belt at locations spaced so that each layer has gelled before the next supply of mixed slurries is fed, whereby a multilayer deposit of gelled material is produced.

16. A method as claimed in claim 15 wherein different layers of the multilayer deposit are of different compositions.

17. A method of forming a food product in the form of shape-retaining pieces, substantially as described in any example.

18. A food product produced by the method as claimed in any one preceding claim.

19. Simulated meat chunks in the form of shaperetaining pieces comprising a uniformly distributed calcium alginate gel matrix, manufactured by reacting a sparingly soluble calcium salt suspended in an aqueous solution of a sugar, polyhydric alcohol or monohydric alcohol with a slurry of comminuted meaty materials containing an alginate derivative.

20. Simulated fruit or other food material in the form of shape-retaining pieces comprising a uniformly distributed calcium alginate gel matrix, manufactured by reacting a sparingly soluble calcium salt suspended an aqueous solution or a sugar polyhydric or monohydric alcohol with a slurry of comminuted materials containing an alginate derivative.

21. Simulated food pieces in the form of shaperetaining pieces comprising a uniformly distributed calcium alginate gel matrix, manufactured by reaci- ing a sparingly soluble calcium salt suspended in an alcohol or polyhydric alcohol that is liquid at the temperature of preparation with a slurry of commi- nuted food material containing an alginate derivative.