GB2148090A - Process for the production of granular protein formed bodies - Google Patents

Abstract

Granular protein formed bodies with caviar-like sensory properties are prepared from an aqueous structuring solution which contains protein which coagulates at an elevated temperature and additives, from which solution coagulated droplets can be formed in a heated layer of oil, wherein the structuring solution consists of stabilised liquid abattoir blood plasma, the protein content of which has been brought to a value of from 7.0 to 10.5% by weight and which has been mixed with the additives, the protein content having been increased by concentrating by means of centrifuging or optionally by the addition of dried protein.

Description

SPECIFICATION Process for the Production of Granular Protein Formed Bodies The present invention is concerned with a process for the production of granular protein formed bodies with caviar-like sensory properties, using plasma from abattoir blood.

The starting point is an aromatised suspension or solution which contains plasma from abattoir blood and gives coagulated, granular protein formed bodies with the desired texture properties, for example of the nature of fish roe or of caviar, by dropping into a heated liquid which is immiscible with water, for example a vegetabie oil.

The process according to the present invention is especially concerned with the nature of the abattoir blood plasma used, the composition of the proteincontaining suspensions or solutions and the structuring and treatment of the granular protein formed bodies for increasing the caviar-like sensory properties.

It is known to produce gel-like granular protein formed bodies which possess the character of synthetic fish roe, for example of caviar.

According to one known process for the production of granular nutrient products described in Federal Republic of Germany Patent Specification No. 1,693,683, proteins of animal or vegetable origin, for example casein, are dissolved in aqueous alkali metal hydroxide solutions and mixed with gel-binding materials, for example gelatine. The starting material is, after the introduction of glycerol, carbohydrates, lipids and lecithins, formed into granules by passing it in an appropriate manner into a liquid which is immiscible with water, for example paraffin oil.

According to another known process described in Federal Republic of Germany Patent Specification No. 1,965,743, the surfaces of the granular nutrient products are made firmer by introducing polysaccharides into the product which are able to form so-called ionotropic gels by reaction with a solution of the salts of at least divalent metals which can be used for foodstuff purposes.

The granular nutrient products produced by the known processes, especially synthetic caviar, are only temperature-resistant up to 50"C. This low temperature stability, which prevents a heat sterilisation, is disadvantageous. Furthermore, the process of production is very complicated and large amounts of raw materials are required.

German Democratic Republic Patent Specification No.125,841 and Federal Republic of Germany Patent Specification No. 2,707,737 describe processes for the production of heat-sterilisable and non-melting granular protein formed bodies from suspensions which have been prepared from mixtures of dry wheat gluten, bovine blood plasma and egg protein, followed by solidification in hot oil.

According to German Democratic Republic Patent Application No. WP A 23 U245 098/3, granular protein formed bodies are produced from freezedried bovine blood plasma by structuring in hot oil, followed by treatment with an aqueous sodium chloride-containing fish brine and thereafter coated with an adhesive fish aroma-containing solution.

Whereas in the case of the processes described in German Democratic Republic Patent Specification No. 125,841 and in Federal Republic of Germany Patent Specification No. 2,707,737, the heat stability is obtained, several protein raw materials are still required for the production of the protein formed bodies. The use of dried protein raw materials is disadvantageous since, in the case of a rapid heat coagulation in hot oil, the degree of denaturing of the proteins substantially influences the texture of the gels formed therefrom.

According to Japanese Patent Specifications Nos.

1,046,750 and 1,046,751, synthetic caviar is produced by dropping aromatised and coloured dispersions, which contain pectin and alginic acid, into calcium hydroxide solution. The dispersions are produced with the use of konnyak mannas. For the aromatisation of the synthetic caviar, the formed bodies are sprayed with oil which contains fish oil, vegetable oil, sodium chloride, sodium glutamate and sodium inosinate. This latter process is different from that of the present invention.

One suggested process contains as protein raw material in the specific examples liquid or freezedried bovine blood plasma. For the aromatisation of the granular protein formed bodies, herring brine is added to the fish aroma-containing solution, together with xanthan as adhesive. When using dried bovine blood plasma, the gel-forming properties of the structuring solution depend substantially upon the degree of denaturing of the protein. If, in the case of dropping the structuring solution into a liquid which is immiscible with water, the protein is to coagulate as quickly as possible to give formed bodies which, after removal from the oil, are sufficiently stable, it has, surprisingly, been found that the use of liquid abattoir blood plasma is advantageous.However, fresh liquid abattoir blood plasma also displays a variable gel-formation behaviour, depending upon the addition of anticoagulation agents which takes place in the abattoir during the obtaining thereof. The reasons for this are clearly of a quite differing nature so that, furthermore, the not always uniform conditions of the blood centrifuging, varying temperatures, standing times and other technological influences can be of importance. This also manifests itself especially, and this has been found to be important, in the non-constant protein content of the abattoir blood plasma.Thus, for example, in the case of the addition of sodium salts of diphosphoric acid as anti-coagulation agents to abattoir bovine blood, in comparison with the use of sodium citrate, the protein content in the abattoir blood plasma is reduced as a result of the decreased ability for calcium complex formation of up to 50%. As has been shown by precise investigations, the highest and most reproducible protein contents in abattoir blood plasma are found in the case of the use of ethylene glycol bis-(2-aminoethyl ether)-N,N,N',N'tetraacetic acid (EGTA), ethylenediamine-tetraacetic acid (EDTA) and other compounds with similar stable calcium complexes.

Therefore, the used of abattoir blood plasma which has been obtained by the addition of sodium salts of diphosphoric acid or of sodium salts of citric acid does not always guarantee a uniform product quality and an objective production of protein formed bodies with the desired texture, for example differing strength and crispness.

It is an object of the present invention to use, for the production of granular protein formed bodies with caviar-like sensory properties, as main component for the protein solution to be structured either liquid or frozen abattoir blood plasma in such a manner that the granular protein formed bodies produced therefrom give the same or selectable texture properties independently of the addition of anti-coagulation agents and of the technical influencing of the processes used for obtaining the abattoir blood plasma.

Thus, according to the present invention, there is provided a process for the production of granular protein formed bodies with caviar-like sensory properties from an aqueous structuring solution which contains protein which coagulates at an elevated temperature and additives, from which solution coagulated droplets can be formed in a heated layer of oil, wherein the structuring solution consists of stabilised liquid abattoir blood plasma, the protein content of which has been brought to a value of from 7.0 to 10.5% by weight and which has been mixed with the additives, the protein content having been increased by concentrating by means of centrifuging or optionally by the addition of dried protein.

According to the present invention, the production of granular protein formed bodies with caviar-like sensory properties takes place from aqueous structuring solutions which consist of abattoir blood plasma and additives, preferably sodium chloride, thickening agents, colouring materials, preserving agents and optionally other components. Depending upon the protein content of the abattoir blood plasma, for the achievement of differing textures, for example strength and crispness, and for the regulation of the gel-forming property, to the abattoir blood there is added, for the adjustment of the necessary protein content, dried abattoir blood plasma, spray-dried or freeze-dried or other protein raw materials forming gels at an elevated temperature of the structuring solution.

The protein content of the blood plasma used can also be increased by centrifuging.

As further suitable protein raw materials forming gels at an elevated temperature, there can also be used liquid or dried egg albumin and acetylated kidney bean protein isolate. The adjustment of the protein content of the structuring solution preferably takes place to a protein content of from 7.8 to 9.0% (N x6.25) by means of spray-dried or freeze-dried bovine blood plasma or of other gelforming protein raw materials. The adjustment of the protein content of the structuring solution or the regulation of the protein content of abattoir blood plasma thus makes possible the achievement of different textures and guarantees a constant gelformation ability of the structuring solution in hot oil.

The structuring solution used according to the present invention can contain 90.0 to 95% by weight, preferably 93.5% by weight, of stabilised abattoir blood plasma, preferably obtained from bovine or pig blood, 0.4% by weight of thickening agent, preferably carob bean flour, 6.0% by weight sodium chloride,0.1 by weight of colouring material and 0.2% by weight potassium sorbate.

Whereas essentially below a 7.0% protein content in the structuring solution, the caviar-like granular protein formed bodies display too soft a consistency, by increasing the protein content to amounts of about 7.8 to 8.7%, there is achieved a good strength and crispness. The aqueous structuring solution can be prepared by centrifuging abattoir blood (bovine or pig blood) in the usual way or also by the addition of appropriate amounts of suitable anti-coagulation agents, for example sodium salts of diphosphoric acid or sodium citrate, the plasma thereafter being separated and adjusted, according to the present invention, by the further addition of heat-regulating protein raw materials to give a protein content necessary for a particular texture.There can thereby be added sodium chloride, colouring material, preserving agents and thickening agents and an aromatisation can possibly also be carried out.

Subsequently, the solution is homogenised, deaerated and possibly filtered or centrifuged for the removal of solid materials. The structuring takes place by dropping the solution into heated oil (95 to 105"C.). After a coagulation time of from 60to 180 seconds, the granular protein formed bodies are sufficiently stable and can be separated from the hot oil and then freed from adhering oil by means of a hot aqueous solution of sodium chloride (5% by weight sodium chloride; 70 to 80 C.). For influencing the flavour of the granular protein formed bodies, this wash solution can be aromatised.

Subsequently, there takes place a coating of the granular protein formed bodies with a salted and aromatised, slimy, adherent liquid which, as thickening agents, can contain vegetable gums, microbial polysaccharides or modified and swolien starches. Besides imparting the flavour, the coating also results in a better adhesion of the formed bodies to one another and at the same time increases the similarity to fish roes.

A preferred coating solution used according to the present invention contains sodium chloride, guar flour, potassium sorbate, citric acid, propyl gallate, a spice aroma and optionally a fish flavour carrier.

After the coating, the granular protein formed bodies are packed into containers and additionally heat-treated for improvement of the storage stability. During this heat treatment (80 to 90 C.), there takes place, depending upon the period of time, a further texture formation which can also be influenced by variation of the protein content of the formed bodies.

The following Examples are given for the purpose of illustrating the present invention: EXAMPLE 1 Ethylenediamine-tetraacetic acid is added in an amount of 1 g./litre to bovine abattoir blood for the prevention of blood coagulation. The abattoir blood is centrifuged at 3800 g and the plasma thereby separated is used for the production of granular protein formed bodies. For this purpose, for the production of the structuring solution, to 933 ml, bovine blood plasma with a protein content of 8.7% are added 4 g. of carob bean flour for increasing the viscosity, 10 g. of foodstuff colouring mixture, 2 g. of potassium sorbate as preserving agent and 60 g. of sodium chloride.After standing for 60 minutes, the structuring solution is de-aerated at33.3x102 Pa and filtered through a 0.1 mm sieve or centrifuged at 3800 g for the removal of coloured materials from the added materials, for example the carob bean flour. The structuring solution thus obtained is dropped through metal canules of 0.53 mm. internal diameter into a 150cm. high column of vegetable oil, the temperature of which is 100 C. Upon dropping down through the hot column of oil, the droplets of the structuring solution coagulate to give formed bodies.After a residence time of 2 minutes, the formed bodies are removed from the column of oil and freed from adhering oil by washing with hot herring brine or sodium chloride brine containing W7% by weight sodium chloride and having a temperature of 70 to 80"C. After the washing solution has dripped off, coating is carried out with an adhesive fish aroma-containing solution in an amount of 100 g./kg. of formed bodies. For pasteurisation, the coating formed bodies are placed in 100 g. conserving tins and pasteurisedfor 20 minutes at 900C.

After the structuring in the column of hot oil, the protein formed bodies have a stable, spheroidal shape. During the subsequent washing process, the spheroidal shape is not changed and the protein formed bodies are not damaged.

EXAMPLE 2 For prevention of blood coagulation, 0.6 g./litre of trisodium citrate are added to bovine abattoir blood and this is then centrifuged as in Example 1. The bovine blood plasma with a protein content of 7.3% which is hereby separated off is used according to Example 1 for the production of granular protein formed bodies. After structuring in the column of hot oil, the protein formed bodies are spheroidal and somewhat softer than those obtained from bovine blood plasma stabilised with ethylenediamine-tetraacetic acid. When carrying out the washing process, the mechanical treatment was carried out with greater care for the avoidance of deformations. After the pasteurising, the strength and crispness of the formed bodies was smaller in comparison with that obtained according to Example 1.

EXAMPLE 3 (Comparative) For the prevention of blood coagulation, to bovine abattoir blood is added stafisal (a mixture of sodium chloride and sodium salts of diphosphoric acid) in an amount of 0.8 g./litre and this is then centrifuged as in Example 1. The bovine blood plasma with a protein content of 6.2% hereby separated off is used in the manner described in Example 1 for the production of granular protein formed bodies. After structuring in the column of hot oil, the protein formed bodies are very soft and do not possess a stable spheroidal shape. In the course of the subsequent washing process, the protein formed bodies are partly deformed and squashed. After pasteurisation, the strength is only slightly increased. The crispness is not very marked. In comparison with Example 1, the pasteurised formed bodies have an irregular spheroidal shape.

EXAMPLE 4 Bovine abattoir blood is stabilised according to Example 3 with stafisal and centrifuged as in Example 1. The bovine blood plasma with a protein content of 6.2% thereby obtained has, according to the present invention, its protein content increased for the improvement of its structurability. For this purpose, in 900 ml. plasma are dissolved 33 g. dried bovine blood plasma and the structuring solution is produced as described in Example 1 and worked up to give protein formed bodies. After removal from the column of hot oil and after pasteurisation, the granular protein formed bodies correspond in their properties to those which have been produced from bovine blood plasma with ethylenediaminetetraacetic acid stabilisation. If only 20 g. of dried bovine blood plasma are dissolved in 900 ml.

plasma, the spheroidal shape is also stable but the consistency and crispness is somewhat smaller.

EXAMPLE 5 Bovine abattoir blood is stabilised with stafisal according to Example 3 and centrifuged according to Example 1. Forthe improvement of the structurability, the protein content of the thereby obtained bovine blood plasma, which has a protein content of 6.2%, is, according to the present invention, increased. For this purpose, in 903 ml. of plasma are dissolved 30 g. of spray-dried acetylated kidney bean protein isolate (degree of acetylation 86.7%) and the structuring solution produced and worked up to give protein formed bodies in the manner described in Example 1. After removal from the column of hot oil and after pasteurisation, the granular protein formed bodies correspond to those which have been produced from bovine blood plasma with ethylene-diamine-tetraacetic acid stabilisation. In the case of the addition of 40 g. of spray-dried acetylated kidney bean protein isolate to 893 ml. beef blood plasma, the strength in comparison with the protein formed bodies which have been produced with the addition of ethylenediamine-tetraacetic acid is substantially greater.

Claims (11)

1. Process for the production of granular protein formed bodies with caviar-like sensory properties from an aqueous structuring solution which contains protein which coagulates at an elevated temperature and additives, from which solution coagulated droplets can be formed in a heated layer of oil, wherein the structuring solution consists of stabilised liquid abattoir blood plasma, the protein content of which has been brought to a value of from 7.0 to 10.5% by weight and which has been mixed with the additives, the protein content having been increased by concentrating by means of centrifuging or optionally by the addition of dried protein.

2. Process according to claim 1, wherein the dried protein used is spray-dried or freeze-dried bovine blood plasma.

3. Process according to claim 1 or 2, wherein, as additives, the structuring solution contains sodium chloride, thickening agents, colouring materials and preserving agents.

4. Process according to any of the preceding claims, wherein the structuring solution comprises 90.0 to 95% by weight of stabilised liquid abattoir blood plasma, 0.4% by weight of thickening agent, 6.0% by weight sodium chloride,0.1 by weight colouring material and 0.2% by weight potassium sorbate.

5. Process according to claim 4, wherein the structuring solution contains 93.5% by weight of stabilised abattoir blood plasma.

6. Process according to any of claims 3 to 5, wherein the thickening agent is carob bean flour.

7. Process according to any of the preceding claims, wherein the plasma used is obtained from bovine or pig blood.

8. Process according to any of the preceding claims, wherein the granular protein formed bodies are freed from adhering oil by washing and subsequently treated with a coating solution.

9. Process according to claim 8, wherein the coating solution used contains sodium chloride, guar flour, potassium sorbate, citric acid, propyl gal late, a spice aroma and optionally a fish flavour carrier.

10. Process according to claim 1 for the production of granular protein formed bodies, substantially as hereinbefore described and exemplified.

11. Granular protein formed bodies, whenever produced by the process according to any of claims 1 to 10.