CA1104408A

CA1104408A - Textured food product

Info

Publication number: CA1104408A
Application number: CA298,185A
Authority: CA
Inventors: Alan J. Vernon; John Stares
Original assignee: Mars Ltd
Current assignee: Mars Ltd
Priority date: 1977-03-09
Filing date: 1978-03-03
Publication date: 1981-07-07
Also published as: SE428521B; NO780640L; AU3402178A; ATA171778A; JPS6257295B2; FR2382865A1; IE46561B1; IT1093790B; NO145596B; DE2810009A1; JPS53113056A; IE780372L; FR2382865B1; AU517082B2; DK104178A; NL7802598A; SE7802649L; BE864596A; PT67742A; LU79201A1

Abstract

TITLE: TEXTURED FOOD PRODUCT.

ABSTRACT OF THE DISCLOSURE

Textured food products having a fibrous, lamellar or striated structure are produced by preparing a mixture of nutritious ingredients and water containing an anionic gelling agent, causing the gelling agent to set or form a gel in the mixture by reaction with a non-toxic metal ion and freezing the mixture with the formation of ice crystals either before, during or after the set of the gelling agent. Divalent or polyvalent metal ions are preferred because these form thermally irreversible gels which maintain in the finished product the textured structure obtained by freezing even in the absence of heat coagulable materials It is, however, preferred to include proteins in the composition for nutritional purposes and the resulting simulated meat products are stable to canning processes. Preferred ionic gelling agents are pectates and alginates.

Description

4~8 ~ackground to _he Tnvention ,},is ir.vention Lelates to a texturea fooa product with a fibrous or striated appearance, resembljng for example the appearance of fibrous meat and provides a process for the production of such food.
It is known to impart a lamellar structure to protein solutions, emulsions and disDersions by freezing the mixture followed by setting the structure by means of the proteins present. For instance, heat coagulation of the protein is described in U.S. ~atent No. 3,~70,~0~ and in BE 838,907.
However these products are often too weak to be used in large scale manuf ctur-ing processes, and furthermore are limited by the requirement of a functional protein, i.e. one that on coagulation in aqueous solution or dispersion yields a coherent; body. A further disad~antage with these processes is the high energy require-ment of the thawing and heat coagulation stages.

Summary of the Invention ~e have now discovered that a food product with a fibrous~lamellar or striated texture, and which is sufficiently tough to ~7ithstand factory handling, can be prepared by a freezina process employing ionic gelling aaents to form the structure. The structure is fixed by the gelation mechanism between the gelling agent, usually an acidic polysaccharide, and a reacting cation but surprisingly this binding can take place before the fibrous or lamellar structure is induced as well as during or after ice crystal for~ation.
A significant advantage of this process is that no further mechanism is reguired to set the structure.

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" '. .':' :' ' ' ' ' . '' , ' ' : , ' According to this invention, therefore, a textured food product comprises pieces of edible material having a coherent fibrous lamellar or striated structure and containing an ionic gelling agent and a non-toxic metal ion reactive therewith. The method according to the invention comprises a method of making a textured food product, which comprises: preparing a mixture of nutritious ingredients and water containing an ionic gelling agent; ~ringing the gelling agent into direct contact with a source of non-toxic metal ion to cause reaction therebetween to form a gel in the mixture; and freezing the mixture with the formation of ice crystals therein either before, during or after the setting of the gelling agent, thereby forming in the mixture a lamellar or striated structure not present in the mixture before freezing.
Description _ the Preferred Embodiments A wide ~ariety of ionic gelling agents and reactive metal ions can be employed. It is, however, greatly preferred that the metal ion should be divalent or polyvalent, for example alkaline earth metals or aluminium because they are much superior in per-formance to monovalent metal ions such as alkali metals.
The gels produced by divalent or polyvalent metal ionswhen used in sufficient concentration have greatly increased stability and, in particular can form thermally stable fibrous or lamellar structures that are resistant to sterilizing heat, for example in a canning process, even in the absence of heat coagul-able substances such as protein.

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The majority of ionic gelling agents are acidic poly-saccharides. The acidic groups may be carboxyl groups as in the case of pectates, alginates and car~oxymethyl celluloses, or they may be sulphate groups as in the case of carrageenin.
Although the fibrous, striated or lamellar structure achieved ~y this process is of particular value in conferring a meat-like texture on products ~

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containing edible proteinaceous material, whether of animal or vegetable origin~ -so as to provide a meat substitute or analogue, the formation of the textured structure does not ultimately depend on the presence of protein in the mixture.
The product may, if required, be preserved by canning, sterilisation or freezing or by incorporation or infusion of sugars, glycerol or other humectants and fungistats such as potassium sorbate. Alternatively the product may be preserved by lowering its pH to a bacteriostatic level and including fungistats.
In the preferred process for preparing the food product of this invention proteinaceous materials and preferably also fat or oil are formed into a solid matrix by the reaction of a non-toxic salt of a metal ion and the salt of an acidic polysaccharide. A lamellar structure is induced by freezing the solid matrix at temperatures less than 273 K and preferably controlling the freezing rate to allow the temperature to fall to 273 K over a period of 2 hours or more to promote large ice crystal formation.
The proteinaceous materials can be of meat, vegetable or bacterial origin, typical examples being fish flesh, muscle flesh, meat offal, meat by-products, gluten (vital or devital), defatted soya flours, soya concentrates, peanut flour, soya isolate, bacterial protein, yeast protein, fungal protein, meat meals, dried blood, structural animal or vegetable protein fibres, greaves, fish meals, blood, bone and keratin.
The inclusion of fats and oils is preferred, but the fat may be an integral part of one or more of the ingredients instead of or as well as a separate ingredient. Emulsi~iers may be added to assist emulsification if desired, although it may be advantageous to have evident lumps of fat embedded in the matrix. Inert fillers such as micro-crys-talline cellulose or silica may be add0d to absorb free fat or oils.

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The non-toxic salt employed in this invention is preferably a cal-cium, magnesium or aluminium salt, but more generally may be any non-toxic di- or polyvalent metal salt. The salt employed will depend upon the method used to set up the protein food. For example, a highly soluble salt such as calcium chloride can be used if the forming process is one of contact be-tween the reactive protein mix and a metal salt solution. On the other hand a less soluble salt such as calcium sulphate is preferred if the setting up process occurs in situ after intimate mixing of all the ingredients.
The preferred acidic polysaccharides for the purposes of this inven-tion are pectates and the preferred forming process is one of an in situ reaction between the metal salt and the acidic polysaccharide. By pectate is meant a very low methoxyl pectin with a degree of esterification (DE) of less than 20% and especially crude pectin sources which contain pectin of a degree of esterification less than 20%. ProYiding the degree of esterification is less than 20% any pectin source may be used at a preferred concentration of Q.1% to 5.0% of pectin based on the weight of product. Citrus peel or pulp which has been treated to produce a pectin of very low methoxyl content is a good example of such crude pectin. However, s~d~um pectates and potassium pectate may be used. Similarly, soluble salts of alginic acid and carboxy methyl cellulose may be used.
Hydrophilic gums and mucilages may be incorporated in the formulation to reduce syneresis of the product which may occur upon thawing.
Suitable colouring agents such as blood, natural and synthetic dye-stuff, e.g. caramel, may be added at any stage. ~lavouring~ and flavour ~ enhancers may also be added.
; Sequesterants may be used either to extract pectin from the crude pectin sources or to slow down the rate of the gelation process. The :: :: . : . , .
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sequesterant may be any non-toxic salt capable of sequestering or chelating with, or making unavailable for gelation, the metal ion causing gelation.
Examples are sodium or potassium salts of tripolyphosphate, citrate, pyrophos-phate, orthophosphate and EDTA.
We have also found that application of this ionic gelling and freez-ing process of this invention markedly enhances the fibrous character of formed structures which prior to freezing already possess some fibrous char-acter. For instance, extremely fibrous products are obtained by this process when hashed fibrous meats are used and are set up using a pectate in situ forming process. It has als-o been found that added water has a beneficial effect on the structure. ~ product with a high added water content exhibits a more fibrous structure after freezing than does a similar product with lower water content.
The process of this invention provides best results when the ice crystal formation takes place slowly. The slower freezing process presumably produces larger ice crystals which provide a more marked structuring effect.
An improved product texture is obtained also if the product is maintained at sub-freezing temperatures for a prolonged period. The inclusion of hydro-philic colloids to reduce the volume of drip loss during the thawing process surprisingly does not appear to affect the extent of structuring brought about during the freezing process.
The process of this invention induces or increases the fibrous appearance of food products which have been "set up" by ionic gelling agents presumably as a result of their freeze-thaw instability and the structure formed is not thermo-reversible. This instability to freeze-thaw cycling is interesting since the sodium salts of the polysaccharides are used to provide freeze-thaw stability in items such as ice creams. ~ixes which have not been ~ 6 -~: . ... . ~ . : , "formed" prior to freezing, but which contain sufficient metal ions to allow gelation with time, react during ~,he freezing process and after thawing ex-hibit the fibrous appearance. Proteinaceous foods containing an ionic poly-saccharide can be frozen in blocks to develop the ice crystals and thawed in solutions containing the reactive metal ions. In such cases the metal ions migrate through the frozen blocks as the ice crystals melt, setting up the structure before it can collapse.
The following Examples further illustrate the invention but are given by way of example only. percentages are quoted on a weight basis unless the context otherwise requires. Example 1 describes the present preferred product.
Example 1 . , %
Meat offcuts (2mm mince) 40,0 Water 26.5 Caramel o 5 CraYy 33 0 100.0 GraYy formulation 20 Treated citrus peel ~DE lQ%)* 6.0 Sodiu~ tripolyphosphate 1 2 Water ~373 K~ 92.8 lQ0.0 The gravy was prepared by mixing the ingredients in a high speed mixer or homogeniser until an homogeneous viscous solution was produced.
The meat offcuts were hashed through a 2 mm plate and mixed with the other ingredients except for the gravy in a bowl mixer with a l'spade"

*Calacturonic acid content 3Q%

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The above noted proportion of gravy was rapidly mixed into the meat, water, and caramel mixture and the resulting mixture poured into trays to solidify. After 2 hours the solidified blocks, which were approximately 1 1/2 inches deep, were placed in a freezer controlled at 258 K for 8 weeks. The temperature of the block centre reached 273 K after 2 hours and was at 258 K
after 8 weeks.
The blocks were conditioned to between 273 K and 278 K before being cubed and sterilised in a typical meat-in-jelly petfood product in metal cans.
After cooling, the cans were opened and the product examined. The product of the inyention was Yery tough with a marked fibrous appearance similar to high quality fibrous muscle meat.
The control product prepared in an identical manner but not subjected to the freezing process, after sterilisation in jellymeat petfood product, did exhibit some fibrosity due to the meat but to a Yery much smaller degree. Also the meat analogue which had been subjected to the process was significantl~
tougher with a more meat-like mouthfeel and chew characteristics than the control.
Example 2 ~raYy ormulation %
Treated citrus peel 2.0 Tetron* Q.4 Water ~373 K) 31.1 33.5 Product ormulation

2 mm hashed meat offcuts 66.0 Caramel Q.5 Gravy 33 5 l'aa. Q
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The gravy was prepared by high shear mixing together of all in-gredients before adding to the meat/caramel mixture. After mixing, the mixture was extruded intermittently into a solution of 10% calcium chloride and allowed to stand in the solution for 25 minutes, after which time the chunks were thoroughly washed with running water. The chunks resulting had a tough skin but a soft unreacted centre. After being stored fcr 5 hours at room temperature the chunks were solid throughout as a result of calcium penetration. The solid chunks were placed in a deep freeze set at 258 K for 24 hours, after which time they were allowed to thaw. The chunks when cut exhibited a fibrous structure f 10 which was stable to sterilisation when canned in a meat in gravy product.
The control product which was not treated to the freezing had a dense non-fibrous appearance similar to lung or kidney. After sterilisation in a meat and graYy formulation the control material remained dense with no evidence of fibrosity. The meat analogue which had been subjected to the freezing process and subsequently sterilised in a similar meat and gravy food product had in contrast the appearance of a good quality fibrous muscle meat, especiallywhen cut open or deformed.
Example 3 , ~
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f. 20 Sodium alginate 1.-33 ~uar gum a.67 Water (293 K) 32.00 ~eat offcuts (2 mm hashed~ 66.00 100.0 Sodium alginate, guar gum and water were mixed in a Z-blade mixer to produce a viscous solution. The 2 mm hashed meat offcuts were mixed in to provide an homogeneous mixture which was then extruded into a weir of 10%
calcium ch]oride solution and cut off with a rotary knife to produce spherical .
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4~8 lumps of meat mix with a tough outer skin and soft centre. The chunks were allowed to soak in 10% calcium chloride solution for 25 minutes before being washed thoroughly. At this point the chunks had a tough skin but a very soft unreacted centre.
The chunks were placed in a deep freeze compartment controlled at 258 K for 24 hours and thereafter allowed to thaw at room temperature.
The thawed chunks were solid throughout and when cut open exhibited a lamellar structure, which was stable to sterilisation in a meat-based product, giving it the appearance of good quality fibrous meat.
In contrast the control product which had been treated similarly but not subjected to the freezing process had a dense lung-like appearance and texture.
Example 4 Product FoTmulation %
Meat mix 67.0 Cravy mix 33,0 Meat mix Pasteurised meat offcuts 63.0 Lactobacillus culture 3.0 Calclum sulphate 2H20 1.0 Gravy mix ; Treated citrus peel 6.0 Tetrasodium pyrophosphate 1.2 Sugar g,Q
Potassium sorbate 1.2 Caramel 4.5 Dye 1.5 Water 76.6 j 100.0 ~ ` ` . ` ' ` ` ~ .
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11(~4~8 The meat mix was prepared by adding the Lactobacillus casei culture to the pasteurised meat offcuts, which had been heated at 373 K for 15 minutes, hashed through a 2 mm plate, and cooled to 313 K. The calcium sulphate was added and the three ingredients were mixed in a bowl mixer using a dough hook.
The Lactobacillus starter culture was prepared by growing the desired strain of microorganism for 20LH in MRS Broth at 303 K.
The gravy mix at 323 K was added to the meat mix (313 K) whilst mixing in the bowl mixer for approximately 30 seconds and the contents were then trans-ferred to a 2-inch deep tray. After 5 minutes, when a pH of approximately 6.4 was achieved, the solid meat block was cut into chunks~ packaged in PVDC pouches and incubated at 303 K for 18 hours by which time the pH of the chunks had fallen to 4.3. The formed meat was firm, having a fibrous appearance similar to stewed steak but was bacteriologically stable.
The product was then deep frozen at 258 K for 36 hours. After thaw-ing out, the chunks exhibited a highly lamellar structure which was superior to the unfrozen material.
Example 5 Product Formulation %
Vital gluten 15.4 Caramel o.s Water t353 K) 9.1 Gravy 75.0 100.0 Gravy Formulation Treated citrus peel 4.5 Sodium tripolyphosphate 0.5 Water ~373 K) 95.0 lQ0.0 The gravy was prepared as in Example 1. To 75 parts of gravy the remaining ingredients of the product formulation were folded in under high shear, - , . - .
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- e.g. in a jar ho~ogeniser, and the mix was poured into 1 1/2-inch deep trays to form. After 2 hours, the solidblocks were placed in a deep freeze at 258 K
for 24 hours. Before freezing the chunks were dense, with a lung-like appear-ance, but after the freezing process had been carried out the thawed chunks had a sponge-like fibrous texture which was stable to sterilisation in metal cans in; a meat and gravy formulation.

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Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method of making a textured food product, which com-prises: preparing a mixture of nutritious ingredients and water containing an ionic gelling agent; bringing the gelling agent into direct contact with a source of non-toxic metal ion to cause reaction therebetween to form a gel in the mixture; and freezing the mixture with the formation of ice crystals therein either before, during or after the setting of the gelling agent, thereby forming in the mixture a lamellar or striated structure not present in the mixture before freezing.

2. A method according to claim 1, wherein the gelling agent is an acidic polysaccharide and the metal ion is divalent or polyvalent.

3. A method according to claim 2, wherein the gelling agent is a pectate and the reactive metal ion is calcium.

4. A method according to claim 1, wherein the said mixture includes proteinaceous material.

5. A method according to claim 3, wherein the mixture is formed into a solid matrix by reaction of the metal ion and the gelling agent and is thereafter frozen, the rate of freezing being controlled such that the time taken for all the product to reach a temperature of 273K is two hours or more.

6. A method according to claim 1, wherein the product after freezing is subjected to a sterilization or canning process, the fibrous, lamellar or striated structure being retained in the now sterilized product.

7. A textured food product comprising pieces of edible material having a coherent fibrous, lamellar or striated structure and containing an ionic gelling agent and a non-toxic metal ion reactive therewith, whenever made by the method of claim 1, or by an obvious chemical equivalent thereof.

8. A food product according to claim 7, wherein the ionic gelling agent is an acidic polysaccharide and the metal ion is divalent or polyvalent, whenever made by the method of claim 2, or by an obvious chemical equivalent thereof.

9. A food product according to claim 7, additionally containing protein, whenever made by the method of claim 4, or by an obvious chemical equivalent thereof.

10. A food product according to claim 7, which is sterilized or canned and retains its fibrous, lamellar or striated structure, whenever made by the method of claim 6, or by an obvious chemical equivalent thereof.