DD148437A3 - PREPARATION OF FISH PROTEIN HYDROLYSATE - Google Patents

Abstract

The invention relates to the production of a fish protein hydrolyzate, in particular from shark meat, using proteolytic enzymes, in particular thermitase, a protease from Thermoactinomyces vulgaris. Goal d. Invention is the better usability of less used fish raw materials for human consumption. The object is to remove, by suitable pre-treatment, undesirable constituents of fish meat (e.g., urea and ammonia in shark meat, lipids, amines, etc.) and to improve fish protein functional properties (e.g., solubility, emulsifiability, disintegrability) by partial enzymatic hydrolysis. For pretreatment, the fish meat is first stirred with dilute acid and then, with the respective separation of the non-soluble precipitate, extracted with weak ethanolic sodium hydroxide solution and with ethanol. The fish protein obtained is either partially hydrolysed after intermediate drying or directly enzymatically and dried. The drying can be carried out as a whole or individually after separation into the soluble and insoluble fraction. At hydrolysis levels up to 10% no bitter taste occurs. The hydrolysates can be used for food or dietetic food preparations.

Description

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Applicant: Academy of Sciences of the Republic of Cuba, Institute of Chemistry and Experimental Biology, Havana

Academy of Sciences of the German Democratic Republic, Central Institute of Nutrition,

2 Bergholz-Rehbrücke

Inventor:

Dr. Basiliano Aldana Limonta

Dr. Ulrich Behnke ²

Prof. Dr. Heinz Ruttloff ²

Production of fish protein hydrolyzate Field of application of the invention

The invention relates to a process for the production of fish protein hydrolyzate (FPH), which can be prepared from shark meat or other fish species or fish waste by enzymatic hydrolysis with good sensory, nutritional and functional properties. These hydrolysates can be used for food or diet food preparations.

Characteristic of the known technical solutions

For the production of FPH, acidic, alkaline and enzymatic hydrolyses are used. These methods have various advantages and disadvantages. By acid hydrolysis (hydrochloric acid, sulfuric acid) can produce mixtures of free amino acids; but this important amino acids, especially tryptophan, destroyed. Furthermore, the final

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product a relatively large amount of acid whose elimination or neutralization is complicated or leads to a high salt content of the product; On the other hand, undesirable humic substances are formed due to the hydrolysis conditions.

Alkaline hydrolysis may result in the racemization of some amino acids, and the final product contains a greater amount of alkali, the removal of which is also not readily possible or results in a high salt load on the preparation. Because of the racemization and possible conversion of cysteine to lanthionine, food quality is degraded.

The erizymatische hydrolysis can cause a negative taste influence by formation of bitter peptides. In addition, such hydrolysates sometimes have an unpleasant odor, which may affect their use. On the other hand, however, the hydrolysis with enzymes gives an FPH of high biological value and better functional properties. For this reason, this problem is being worked on with the aim of obtaining a hydrolyzate with a better taste and smell, which is suitable for use in foods. According to the known literature and patent specifications for the production of FPH, various methods have been proposed, all of which are based on the following principle:

The starting material is an aqueous slurry containing 20-30% of fish or fish products whose pH is adjusted for hydrolysis by the addition of alkali or acid (enzyme-dependent). The hydrolysis with animal, plant or microbial proteases takes place at the pH and temperature optimum of the enzyme used. The mixture is treated after hydrolysis with a solvent until the defatted fish hydrolyzate is virtually odorless and tasteless, and then dried. The dry substance consists essentially

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from peptides and amino acids.

The protein content of FPH and the values of the essential amino acids are similar to the fish protein concentrate. In particular, a high lysine value (% 10.5 g / 16 S N) can be observed. In general, the functional properties of FPH are more favorable than those of FPK. A disadvantage of the product is the bitterness, which depends mainly on the degree of hydrolysis.

There is no knowledge about the use of shark meat for the production of FPH. As the most important ingredient in human nutrition, fish meat contains biologically high-quality protein, which, together with that of mammalian and poultry meat and milk and eggs, is at the top compared to other proteins, and shark meat and meat from other cartilaginous fish are the proteins mentioned in this regard The protein content, based on the crude protein (N × 6.25), is 18.1%, and has a high lysine and tryptophan content in comparison with egg and milk protein, as well as other N-containing shark muscle Ingredients (non-protein nitrogen, especially urea) that can be of importance for both flavor and spoilage Because of the high urea content, ammonia is formed very rapidly after the animal dies in part, products are made whose names do not recognize their origin; Holographic considerations have led, in lieu of the deterrent name "shark," to other designations that have been well received by the consumer (eg. B. "Schillerlocke" and "sea eel" from spurdog; "Veal fish" from pork shark; "Bacon fish" from gray shark). Due to the mentioned disadvantages, the main amount of shark (300 - 400 kt per year) is fed to animal nutrition. The FPH offers a way to make the shark protein for the human

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To use nutrition.

Object of the invention

Purpose of the invention is the production of FPH with neutral, in particular not bitter taste, high nutritional value and favorable functional properties, preferably from shark meat.

Explanation of the essence of the invention

The invention has for its object to show the special conditions for the recovery of such J ¹ PH. The production of FPH can be based directly on shark meat or other species of fish, or it can first be processed into fish protein concentrate (FPK) according to the first pre-treatment stages. produced and stored, .When subsequently the enzyme action takes place. For the preparation of the fish meat, the hydrolysis and the working up, the following procedure according to the invention has proven to be particularly suitable:

The comminuted fish meat is used to remove unwanted compounds (eg urea, ammonia, amines, odorants and flavorings, etc.) with the 2-5fa ^c k ^en ) preferably 3 - 4 times the amount 0.05 - 1%, preferably 0, 1 - 0.25% phosphoric acid at temperatures of 50 - 70 ⁰ C, preferably at 60 ⁰ C, 1-5 h, preferably 2-4 ii, kept in motion and then the residue separated. The latter is stirred to remove lipids with 0.01 to 1%, preferably 0.05 to 0.1% strength, ethanolic sodium hydroxide again 0.5 to 5 k, preferably 1-3 h ^ stirred and the insoluble, separated protein content 1-3 times, preferably 2 times, during 10-60 min, preferably 15-45 min, with ethanol at 30-60 ⁰ G, preferably 40 50 ⁰ C, extracted. The FPK thus obtained, after separation from the suspension, can be dried in vacuo and stored as storable

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Intermediate stored.

The residue or the PPK are brought to a protein content of 4-10%, preferably 6-8%, with 0.05% sodium hydroxide solution and adjusted with hydrochloric acid to a pH suitable for the enzyme to be used (for thermitase, for example pH 9). After mixing, a protease, ζ. Thermitase (a protease from Thermoactinomyces vulgaris; DD-WP 112 662, DD-WP 106 130), bromelin or another protease is added, and it is added with stirring at a suitable temperature for the enzyme used (40-70 ⁰ C, . thermitase z for example 50 - 60 ⁰ C) -3H 0.5, preferably 1-1.5 &> incubated. According to the invention, the amount of enzyme is metered in such a way that the hydrolyzate has a degree of hydrolysis (proportion of hydrolyzed peptide bonds of the starting protein, determination of released NH.sub.2 groups Ze.sub.B.sup.2 with 2,4,6-trinitrobenzenesulphonic acid) of 0.5-10%, depending on the desired functional properties (eg, solubility, foamability and foam stability, emulsifiability and emulsion stability, water binding capacity, among others, which are all dependent on the degree of hydrolysis). To inactivate the enzyme activity is heated to 100 ⁰ C within 30 min. A mixture of a protein precipitate and a soluble FPH fraction is obtained, which is dried together or separately (for example vacuum drying, spray drying, freeze drying) and stored. The optionally desired separation of the hydrolyzate into a soluble and an insoluble fraction takes place at a predetermined pH, z. B. pH 4.0. Fish protein partial hydrolyzates with hydrolytic levels above 10 % show increasing bitterness. The resulting products are white to light cream, odorless and of neutral, non-bitter taste and are intended for use in food or diet foods.

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embodiments Example 1 .

25 kg of minced shark meat _(Ä 3J9 kg protein) with the 3> 5-fold amount of 0.2% phosphoric acid at 60 C for 3 hours and then centrifuged kept in continuous motion. The precipitate is stirred for 2 hours at room temperature with 0.05% strength ethanolic sodium hydroxide solution. Then the insoluble protein content obtained after centrifuging again is extracted twice with ethanol at 40 ^° C. for 30 minutes. The residue is adjusted with a 0.05% sodium hydroxide solution to a protein content of 8 % , brought to pH 9> 0 with 1 Ν and 0.1 N hydrochloric acid and stirred at 50 ⁰ C for 10 min. Thereafter, the required amount of thermitase is added and it is incubated with stirring at 50 C for 1 h. To inactivate the enzyme activity is heated to 100 ⁰ C in the course of about 30 min. Centrifugation gives a protein precipitate and the soluble FPH in the supernatant. The protein sediment is dried in vacuo and pulverized in a colloid mill (ie 2.2 kg protein). The supernatant is spray-dried after concentration in vacuo (2, 1.3 kg protein).

Example 2

Same procedure as in the first example, but after the inactivation of the enzyme, the mixture is concentrated in vacuo and freeze-dried or spray-dried.

Example 3

Same procedure as in the first example, but after the inactivation of the enzyme, the mixture is adjusted to pH 4 with 1 N and 0.1 N hydrochloric acid and then centrifuged for 30 min at 4 Q. Sediment and soluble fraction are dried.

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Example 4

The FPK prepared from shark meat is adjusted to about 8% protein with a 0.05% sodium hydroxide solution and mixed. Then the process is optionally continued according to example 1, 2 or 3.

Claims (6)

-a- 2 169 15 invention claims 1. A process for preparing a Fischproteinhydrolysates, characterized in that fish meat, in particular shark meat, successively an acidic, alkaline   and subjected to ethanolic pretreatment with respective separation of the insoluble protein portion and this is subsequently hydrolyzed with a protease, preferably thermitase. 2. The method according to item 1, characterized in that the acidic pretreatment with a 0.05 to 1%, preferably 0.1 to 0.25% phosphoric acid in 2 to 5 times, preferably 3 to 4 times the amount at 50 to 70 ° G, preferably at 60 ⁰ C, while 1 to 5 h, preferably 2 to 4 h, is carried out with stirring. 3 · Method according to item 1 and 2, characterized in that after centrifuging the precipitate of the acidic pretreatment of this 0.5 to 5 h, preferably 1 to 3 h, at room temperature with 0.01 to 1%, preferably 0.05 to 0.1%, ethanolic sodium hydroxide solution is pretreated. 4. The method of item 1-3 », characterized in that the centrifuged precipitate of the alkaline pretreatment 1 to 3 times, preferably 2 times, for 10 to 60 minutes, preferably 15 to 45 minutes, with ethanol at 30 to 60 ⁰ C.
is extracted. at 30 to 60 ^° C., preferably at 40 to 50 ^° C., Process according to items 1 to 4, characterized in that the extracted with ethanol fish protein with 0.05% sodium hydroxide solution to a protein content of 4 to 10%, preferably 6 to 8%, and then with hydrochloric acid to the pH required for the respective enzyme Value, preferably for thermitase to pH 9 ". -j- 2 169 15 is presented. 6. Process according to item 1-5 », characterized in that the enzymatic hydrolysis for 0.5 to 3 h, preferably 1 to 1.5 h, at 40 to 70 ⁰ C, for thermitase preferably at 50 to 60 C, with stirring is carried out. 7 · Method according to item 1-6, characterized in that the amount of enzyme is metered so that the degree of hydrolysis is in the range of 0.5 to 10%. 8. The method according to item 1-7 », characterized in that is heated to 100 g for inactivation of the enzyme within 30 min and then cooled to room temperature. 9. The method according to item 1-8, characterized in that the hydrolyzate is optionally dried in total, or that after separation of the hydrolyzate at a predetermined pH, for. B. 4.0, in the soluble and the insoluble fraction in each case both fractions obtained are dried individually.