JPS6246140B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Protein fortification of acidic foods with a PH in the range of 2 to 6 is complicated in that proteins exhibiting satisfactory nutritional and taste properties are not available. Oilseed proteins, particularly soybean proteins, when converted to acid-soluble form, are characterized by undesirable taste characteristics variously described as green and bitter. Offensive flavors are particularly noticeable in acidic beverages where protein concentrations of 2-8% or more do not contain enough other ingredients to mask strong flavors.

Hydrolysis of seed proteins by the action of proteolytic enzymes is a well-known process that yields water-soluble products that can remain soluble or partially soluble under acidic conditions. Known methods of oxygen decomposition are disclosed in Patent No. 3814816, Patent No. 3830942, and Patent No.
3843802 and Patent No. 3846560.

According to conventional methods, the protein is separated from the seeds in a water slurry. Add proteolytic enzyme to the slurry.
Adjust the pH to optimize reaction conditions for the specific enzyme used. The slurry can be heated before addition of the enzyme and during enzyme decomposition.

The polypeptide mixture produced by enzymatic hydrolysis is water soluble at acidic or neutral pH, but has a stronger flavor than the initial protein isolate. Therefore, it is desirable to reduce strong or young flavors while retaining acid solubility.

The present invention improves the taste characteristics of hydrolysates obtained by enzymatic hydrolysis of oilseed proteins. The hydrolyzate is chemically modified by reaction with an acylating agent, preferably a dicarboxylic acid anhydride such as succinic anhydride. By this method, free amino groups of the polypeptide are acylated, which substantially improves taste, especially in acidic solutions.

Acylation of proteins themselves is a well-known process. For example, in Patent No. 3764711, the patentee obtains a coffee whitener by acylating unhydrolyzed soy protein. However, the same patentee has shown that acylation of pre-hydrolyzed proteins results in products with undesirable taste characteristics. It is also stated that acylated hydrolyzed proteins are insoluble in acidic solutions.

It was unexpectedly found that acylation of enzymatic hydrolysates resulted in substantial improvements in taste properties, while the products remained soluble in acidic solutions.

The present invention is applicable to enzymatic hydrolysis of acid-soluble soybean protein. Naturally, one would expect application in exactly the same way to similarly isolated proteins of peanut, cotton, corn, rapeseed and sesame. It has been found that the method of the invention cannot be applied to animal proteins.

Seed seeds, such as soybeans, are first processed to separate the protein. For example, soybean flour has a rating of about 7.5 to about 9.5.
It can be extracted with a weak alkali having a PH.
The aqueous extract is separated from the solid fraction and then
Adjust the pH to approximately 4.5 to precipitate the protein. Precipitated proteins can be washed and then subjected to enzymatic hydrolysis.

The aqueous slurry of soy protein can be heated at temperatures of about 93° to about 129.5°C (about 200° to about 265°) for a period of time without degrading the full flavor of the final product. Heating times of 1 to about 25 seconds, depending on the temperature, are generally sufficient.

The partially denatured protein is then treated with a proteolytic enzyme, preferably under slightly acidic or basic conditions. Suitable enzymes include plant or animal neutral and alkaline protease enzymes, endopeptidases such as pepsin, fuicin, papain, reinin, trypsin and chymotrypsin, as well as microbial exopeptidases such as aminopeptidases and carboxypeptidases A and B.

The PH and concentration of the slurry can be adjusted to ensure maximum activity of the selected enzyme according to well-known principles. Preferably the protein concentration should not exceed 20%. The amount of enzyme used and the degradation time may vary depending on the type of enzyme used, temperature, PH, and such factors can be determined by one skilled in the art. The temperature is generally raised to a level above room temperature, but at a level that deactivates or denatures the enzyme, generally around 71°C (approx.
160〓) or less.

Enzymatic hydrolysis is a major proportion of protein, preferably
Continue until 60-85% is hydrolyzed and then terminate. The resulting polypeptide mixture has a wide range of
It will dissolve in a solution with a PH value. However, for purposes of the present invention, the mixture will dissolve in a solution having a pH of 2 to 6. After removing any insoluble fractions, the solution can be dried.

The isolated protein is then brought into solution and acylated in the customary manner. The acylating agent is oxygen with a substitutable hydrogen atom that provides a site for reacting with the agent;
It is a compound that can acylate functional groups in protein hydrolysates, such as sulfur or nitrogen. Suitable agents are either internal or external, such as monocarboxylic anhydrides, including acetic anhydride and propionic anhydride, and dicarboxylic anhydrides, such as succinic anhydride, glutamic anhydride, and maleic anhydride, as well as mixtures thereof. Contains carboxylic acid anhydride. Succinic anhydride is preferably added as a solid to the hydrolyzate solution maintained at a neutral pH of about 7.0 to about 7.2. Preferably, the solution is cooled to a temperature of about 1 to about 15°C during the reaction.

Specifically, the reaction solution contains approximately 30% of the protein hydrolyzate.
Contains ~15%. Sufficient acylating agent is added and
Typically from about 7 to about 18% of the available functional groups, based on the weight of the hydrolyzate, are reacted substantially completely. Addition of a 0.08 Molar saline solution may be necessary for solutions containing polypeptides that would otherwise not dissolve at neutral PH and require increasing the ionic strength of the solution in order to dissolve. The acylating agent is added to the solution thus prepared and the pH adjusted to neutral or slightly above by addition of a suitable base such as caustic potash, caustic soda or the like. The pH is preferably maintained at 7.0 to 7.2 by continuous titration until the acylating agent is completely dissolved and the reaction is complete. Inorganic salts formed by the reaction can be removed by dialysis, electrophoresis, reverse osmosis or other suitable desalting techniques. The solution can then be dried to obtain a solid carboxyacylated hydrolyzate.

The product thus obtained has a very mild odor and flavor and exhibits no unpleasant flavor when dissolved in acidic solutions having a pH of about 2.0 to 6.0. The product is thus particularly suitable for addition to acidic beverages, including natural or artificially acidic fruit beverages. Suitable beverages include, for example, sweet orange and tomato beverages. The product is also suitable for addition to carbonated drinks.

Example: In the production of a soft-tasting acid-soluble protein, 134 g of enzyme-hydrolyzed soy protein (type 1205,
Gunther, Division of Staley) in water.
of distilled water. The pH of the solution is 4.46 and the temperature is
The temperature was 2.8℃ (37〓). 12.5ml NaOH (5N) was added to the solution to bring the pH to 7.05. Succinic anhydride (11.7
Sprinkle g) slowly over the reaction mixture, while
PH of 7.0-7.2 by continuous titration with NaOH (5N)
was maintained. Approximately 48 ml of caustic soda was used for this titration.

If the pH is kept constant, the reaction mixture is diluted with water using a hollow fiber dialyzer once the reaction is indicated to be complete.
One gallon of distilled water was dialyzed five times, changing every 20 minutes. The reaction mixture was then lyophilized.

EXAMPLE Three different types of enzymatically hydrolyzed soy protein, Gunther type 1205, Gunther type 1043 and Central Soya type FS704, were amber-oxidized according to the example. An orange drink was prepared and divided into three portions. Equal amounts of amber oxidized moieties were added to equal amounts of orange beverages and taste tested. The same sample containing the same amount of protein without amber oxidation was prepared for comparison. Taste improvements with amber-oxidized protein were observed in all cases, including a reduction in soy flavor and bitterness.

Example Reconstitute 100 ml of natural orange juice beverage fortified with 3.7% frozen orange juice concentrate with amber oxidized acid soluble soy protein (by analysis
% protein) was added to produce 4.66 g.

EXAMPLE A protein enriched, natural orange juice concentrate was prepared by adding 33.12 grams of amber oxidized acid soluble soy protein to 6 ounces of orange juice concentrate. When reconstituted with 18 ounces of water, this concentrate yields 37% protein-enriched natural orange juice.

Example A 4.0% protein fortified artificial orange juice drink was prepared by dissolving the following formulation in 100ml of cold water: Sucrose 11.5g Citric acid, anhydrous 1.0g Cellulose gum 0.1g Orange flavor as needed Orange color as needed Amber oxidized acid soluble soybean Protein 5.0g Example A 50% natural, 50% artificial orange youth beverage fortified with 3.8% protein was prepared by mixing with an equal amount of the beverage as described in Example and above.

Example: 4.0% protein fortified carbonated natural orange juice drink reconstituted to 200 ml of frozen orange juice concentrate, 10.0 g of amber oxidized acid soluble soy protein was added and the beverage was then carbonated in a pressurized carbon dioxide cylinder. Manufactured by

Example A 4.0% protein-enriched artificial tomato youth beverage was prepared by dispersing the following formulation in 8 ounces of cold water: Tomato powder 30.0 g Salt 1.2 g Citric acid, anhydrous 1.0 g Tomato flavor as needed Amber oxidized acid soluble soybean protein White 12.0g The beverages described in the examples and descriptions are representative acidic beverages that can contain the modified protein of the present invention. All these beverages are delicious and free from excessive bitterness and unpleasant soy flavors.

Claims (1)

[Claims] 1. In the production of a modified protein food having a mild flavor, the protein obtained from oilseed seeds is first hydrolyzed with a proteolytic enzyme to form an acid-soluble polypeptide mixture; A method for producing the protein food described above, characterized in that the mixture is acylated to form an acylated hydrolyzate. 2. The method according to claim 1, wherein the protein is soybean protein. 3. The method of claim 1, wherein the acylated hydrolyzate is soluble in an acid solution having a pH of about 2 to about 6.