NO781204L - PROCEDURES FOR AA PREVENT GELING IN HERMETIZED PROTEIN-FOOD FOODS - Google Patents

Description

Method for preventing gelation in canned protein foods.

The present invention relates to a . method for • preventing gelation of the liquid phase in a canned protein-containing food. ■ In particular, the invention relates to a method for reducing or eliminating gelation, whereby special agents are added directly to the proteinaceous, solid substance, which agents serve to disperse, break down, absorb or coagulate the gelatin therein.

The experimentation of canned meat-containing foods such as beef and stew as well as meat- and sauce-type pet food is the result of continuous research by food technologists and pet food specialists for the development of easy-to-serve meat and prepared meat-containing foods . Mainly because of the processing method associated with the protein content of such products. problems have arisen with the tendency of the liquid portion of canned, liquid and protein-containing solid foods to gel when stored at room temperature or lower. For example, in the case of canned meat and sauce-type pet food, when such a product is processed by heating in the usual canning operations, the gelatin in the meat will be released and leached into the accompanying sauce. On cooling, the gelatin tends to gel the sauce. and. spoil the appearance and consistency of the sauce. Even in the case of "homemade" sauces prepared at home from the broth of the cooked meat, a common phenomenon is the gelling of the sauce by freezing. In all cases, this is due to the protein that has become

extracted from the meat, or generally speaking from the proteinaceous solid when this is exposed to elevated temperatures.

■In the case of canned products, the extraction is primarily due to the sterilization process which necessitates high temperatures", whereby the collagen or the gelatin derived from the collagen is extracted and hydrogen bonding takes place, resulting in cross-linking of the same on cooling and finally gelation.

It has been found that the direct addition of certain edible protein reactants and absorbents to the proteinaceous solid phase of a canned liquid and proteinaceous solid product prevents gelation of the liquid portion. under storage..

According to the invention, a method has therefore been provided to prevent gelation in canned protein-containing products. products that have a liquid and a solid protein-containing phase, whereby an edible protein reactant or absorbent is added to the solid, protein-containing phase before sterilization, the amount of which is sufficient to prevent gelation of the liquid phase after sterilization.

Included in the term "protein reactants" are protein dispersants, protein coagulants and protein degrading agents. Especially when protein dispersants, such as monovalent salts, especially sodium iodide, are added. the proteinaceous, solid substance, these tend to prevent gelation by disaggregation of the protein. The protein's gelation potential is thus reduced when the temperature is lowered, which makes it possible for gelation to only occur at significantly lower temperatures than normal. The protein coagulants, e.g. the lower ester pectins and gums containing acid groups, such as gums

■ arabicum etc.,' causes aggregation rather than. disaggregation of the gelatin by ■preventing gel formation. Although the protein dispersants and coagulants work in completely different ways, they share in common an effectiveness at the point of release of the gelatin into the solid. That is that heating triggers the release of gelatin, and it is at this point that the dispersants and coagulants serve to either disaggregate or aggregate the gelatin molecules, respectively, so that they prevent the formation of a gel by blocking the gelatin's release into the liquid. Protein-degrading agents, e.g. proteinases, on the other hand, serve to break down the collagen and gelatin. This occurs in the proteinaceous solid before the sterilization temperature is increased to the enzyme protein's denaturation point, whereby the amount of extracted gelatin is limited.

The absorbents that are not included; in the term "protein reactants", includes gums which do not contain acid groups, e.g.

methylcellulose and free absorbent starches. which is included

.raw starches as well. such as pregelatinized starches. By "free" is meant an absorbent starch whose function as an absorbent is not determined by anything. beyond one's own nature. For example, flour contains an absorbent starch, but it exists as particles intimately associated with gluten. The absorption properties of starch are prevented by the gluten, which is why starch in the form of flour cannot be considered a free absorbent starch. Cross-linked or granulated, stabilized starch serves particularly well to immobilize the gelatin in the solid, thereby preventing its extraction into the liquid. This last category of antigelling material is preferred over the protein reactants mainly because of their ease of use and because of their economy. Furthermore, the cross-linked starches have been shown to have an anti-browning effect on protein-containing, solid substances which have been subjected to heat treatment and thus exposed to a drying atmosphere. For that reason, they are the preferred compounds in this class of anti-gelling agents.

Anionic polymers, such as gum arabic, gum ghatti, or a combination thereof, when added to the sauce portion of the foodstuff, are generally found both to significantly prevent the extraction of protein from the meat and into the sauce when the mixture is exposed to high temperatures for reasons of for sterilization etc.;. , and to prevent gel formation in the minimal amount of gel-forming protein that had to be extracted.

The mechanism of this side of the invention is not completely out

■understood, but it has been determined that the ability of these polymers to prevent gelation is directly related to both the anionic properties of these compounds and the amount of extractable ..protein present in the system.. As a result, .certain anionic polymers can be effective in one area of protein,

content, they may be partially or completely ineffective in a higher area of the same. The gums of the present invention have been found to be particularly effective when the protein content varies

from approx. 15 to approx. 35%. However, it is not desirable to request limit the invention neither to this protein region nor to the gums which have been found to be effective therein since numerous other anionic polymers, such as sodium carrageenate, xanthan gum, tragacanth, sodium alginate and caraya gum, although not so appreciably effective in the aforementioned protein range, they will have a powerful effect at their maximum efficiency level where the protein range is significantly varied. It is likewise not intended to limit the invention to the limits of a meat and sauce system, but rather is intended to encompass all foodstuffs and pet food which have as a common parameter a proteinaceous solid in a liquid system.

For the sake of brevity, for the part of the invention which concerns the addition of protein reactants and absorbents to the solid phase, in the following, reference will only be made to a meatball and sauce system, but it is not intended to limit the invention only to such system. On the contrary, the present invention is intended to include other foodstuffs and pet food which have as a common parameter an animal, proteinaceous, solid substance in a liquid system.

According to the method according to this side of the invention, effective amounts of a protein reactant or

- absorbent directly to the .meatball and thus mixed.. The class- of edible protein reactants-is . includes protein dispersants, protein coagulants and protein degrading agents. Protein dispersants include urea and edible monovalent salts such as sodium thiocyanate, sodium salicylate and sodium iodide, the latter being the preferred dispersant in this class of protein reactants. As previously mentioned, the ctspergeringinidels are active after heating the meatball, since it is at this point that the gelatin is activated. The dispersants serve to disperse the gelatin aggregate.e. The protein coagulants are similar to the dispersants in that their effectiveness is triggered by the ppp heating process - at which point the gelatin is released. This class of protein reactants causes the gelatinous material to aggregate into a cohesive mass in the meatball rather than dispersing the potential gelling components. The gelatin is therefore prevented from being washed out in the sauce, mainly due to the gelatin particles being captured by the binder.-'Included in this class of protein reactants are the -tannins,' tannic acid, lower est.erpectins such as lower methoxy. pectin, divalent and trivalent salts, such as magnesium sulfate and calcium chloride, and gums containing acidic groups, such as gum arabic, carrageenates and alginates, gum arabic being the preferred protein coagulant.

The protein degrading agents are the third and last class IV protein reactants. These compounds differ from the dispersants and coagulating micelles in that they serve to prevent gelation before the meat undergoes any kind of heat treatment. By thus breaking down the gelatin, they effectively prevent gelation by limiting the amount of gelatin that is present. extracted during the heating process. Simple heat degradation is one means of protein degradation, but it is time-consuming, expensive and forms no part of the present invention. Protein-degrading agents of the present invention include edible proteinases, edible acids and edible alkali. Because of the often-accompanying aftertaste the use of these acids and bases, the proteinases are the preferred protein degrading agents in the present invention.

Of the three categories of protein reactants, the protein coagulants are preferred. This is mainly due to the fact that. the dispersants, dispersants and disintegrants have harmful effects on the proteinaceous solid into which they are incorporated. Especially when dispersants are used, the cohesion of the solid will change, producing a crumbly, crumbly product which is highly undesirable in a meatball or a meatball type product where shape retention is desired. In the case of proteolytic agents, consistency control is the main problem. as it is difficult to determine the exact degree of degradation and consequently reduction of coriceptance that will take place.

The second main category of compounds. for this part of the invention are, as previously mentioned, the absorbents, especially gums containing non-acidic groups. for example, methyl cellulose, propyl cellulose and the free absorbent starches. Most starches are effective for use in the present invention. Most preferred, however, are the chemically modified, gr.annular or cross-linked starches., such as. obtained by treatment with epichlorohydrin or the phosphates. Because of their cross-linked structure, the stabilized starches generally have less tendency to swell and burst when they absorb the gelatin solution during sterilization.

The concentration ranges for the compounds used in this part of the invention can vary widely both with

consideration of the effectiveness of the particular protein reactant or

-absorbent and with regard to the protein concentrations in the particular system in question. In general, however, a typical meatball requires

and sauce system usually from 0.01.?! to 5% of the anti-gelling compound based on the weight of the meatball, a range of from 1% to 3% being preferred. Concentrations higher than<<>5% can of course be used, but will be impractical from an economic point of view and will in some cases produce consistency problems..

While different methods of combining the proteinaceous solid, especially the meatball, with the protein reactants and absorbents can be used, such as sprinkling the anti-gelling compounds on the outside of the meatball or spraying solutions

.of these agents at the same time, the most convenient and effective method is simply, simply, to mix these agents with the meat before it is cooked.. When everything is homogeneously mixed, these agents will serve to either disperse, form, precipitate or .break down the gelatin. Resul-

The results of several experiments conducted to determine the effectiveness of these compounds are listed in Table I. The concentrations

■ of the compounds is based on the weight of the meatball. The gelling potential of the sauce was determined on a "Gel Characterization. Apparatus" ("GC.A") after the gel had been formed, separated and cooled under standard conditions at 10°C. The Gel Characterization Apparatus ("GCA") is essentially a gelometer consisting of a piston that measures the gel strength of a liquid after the piston has

penetrated the liquid to a depth of approx. A, etc. The amount of "GCA" units therefore proportionally represents the degree of gelation that has taken place, assessed against a blank. In the immediate experiment, the additives were added to the meat in a pulverizing mixer, and roughly shaped meatballs. was cooked under air access at approx. 315°C for 3g min.

Although all compounds covered by the present invention are effective in significantly reducing the gelling potential of the sauce after treatment, it has been found that certain of these compounds tend to affect the consistency of the prepared meatball. to produce a weak rubbery character. For this reason and because of the numerous advantages of using the absorbent starches, these are the preferred anti-gelling agents in the present invention. In addition to the fact that they are easier to work with and more economical to use, the absorbent starches reduce the chances of meat browning when the meat is exposed to the atmosphere. This will be the case when meat is left uncovered in the refrigerator or kept at room temperature on a dog plate. This is primarily due to the substantial extraction of amino acids and lower polymeric amino acids from

■meat<t>. Moreover, their use results in a moister meatball due to the starch's water retention when the meatballs are exposed.

for air. Because of the ability of the cross-linked or stabilized starches to absorb the gelatin and water during sterilization

with less tendency to swelling and bursting, these starches are extracted, especially such starches are obtained by treatment with epichlorohydrin. The use of epichlorohydrinrnod in f ized, cross-linked starches 1 concentrations varying from . 1% to 2% on the basis of its weight

protein-containing solids therefore represent the pre-

drawn embodiment of the present invention.

For a clearer understanding of the invention, reference is made to the following examples which illustrate representative methods of. the invention-, but which is not intended to be exhaustive of the same.

Example 1

Five separate and equal portions of frozen meat were ground with appropriate amounts of vitamins, minerals and flour to obtain

other of base masses that weighed 1.135 kg. and of which the meat made up 95%. To these base materials was added one of the following fixing agents, the concentrations of which were calculated on the weight of the base material.

.Sample 1,- 0.5% tannic acid (56.8 g)

Sample 2 - 1.0% gum arabic (113.5 g)

Sample -3 - 1.0% stabilized starch (113.5 g) - Sample 4 - 1.0% sodium iodide (113.5 g)

Sample 5 _ blank sample no addition The mixtures were thoroughly Unbreathed until obtaining ■ homogenous mixtures. Each mixture was then extruded and cut into pieces. The pieces of meat were fried -in 3g rnin. at 315°C.

A dry sauce mixture was prepared by -mixing hydrolysed pieces of vegetables, spices, flavorings and salt...Hot water was then added to the dry mixture and heated while stirring to approx. 85°C and held at this temperature for approx. 10 minutes

The pieces of meat were then added to the sauce mixture, packed in cans and sterilized at 121°C for 75 min. After cooling

five cans were opened, and only the blank sample fell short of giving the appearance and consistency of a canned meat and sauce product because it was gelled. The other four samples showed no sauce gelation and had the desired pourability.

Example II

The same procedure as in example I was used, with the exception that a sample containing 1 percent by weight of MgSO^ based on the base mass was evaluated against a blank sample that did not contain any addition. For the blind test, the 9th was achieved

same results with gelation, which was completely eliminated by the use of MgSO^.

EXAMPLE III'

The same procedure was used, as in Example I for the preparation and cooking of the meatball portion of a meat and sauce type product. In this test, a starch that had been modified with epichlorohydrin was compared to a blank at the 1 level. The meatballs were assessed with regard to both taste and appearance. When exposed to a drying atmosphere after canning, browning could not be observed in the sample with modified starch, and moreover this sample contained more moisture. •

Claims (9)

1. Method for preventing gelation in canned, protein-containing foods that have a liquid phase and a solid, protein-containing phase, characterized in that an edible protein reactant or absorber is added before sterilization bent to the solid, proteinaceous phase, the amount of which is sufficient to prevent gelation of the liquid phase after sterilization. 2. Method as stated in claim 1, - characterized in that the protein reactant is a protein dispersant, a protein coagulant or a protein degrading agent. 3. Method as set forth in claim 2, characterized in that the protein reactant is urea, a monovalent salt, a tannin, tannic acid, a lower ester pectin, a divalent or trivalent salt, an acidic group-containing gum, a proteinase, a edible' acid or an edible alkali.. 4 i Process as stated in claim 3, characterized in that the protein reactant is sodium thiocyanate, sodium salicylate, sodium iodide, magnesium sulfate, calcium chloride, gum arabic, carrageenate or alginate. 5. Method as stated in claim 1, characterized in that the absorbent is a free-absorbent starch or a gum containing bic acid groups. 6. Method • as stated in claim 5, characterized in that the absorbent is a chemically modified, cross-linked starch or methyl cellulose. 7. Method as stated in claim 6, characterized in that the absorbent is a starch chemically modified with epichlorohydrin. 8. Procedure as specified in requirements. 1 to 7, characterized in that the non-toxic protein reactant or - absorbent is added in an amount of from 0.01 to 5% by weight. on the basis of the proteinaceous, solid substance. 9. Method as stated in claim 8, characterized in that the reactant or absorbent is added in an amount of from .1 to 2% by weight on the basis of the proteinaceous, solid substance.