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What Is Soy Peptide Exactly?

Dec 17, 2019

First, I will ask you a question that what is soy peptide exactly? It is an active peptide, which obtained by micronizing soybean protein. The average length of the peptide chain is 3 to 6 amino acids.  In order to be released from soy protein, the amino acid obtained is basically the same as that of soy protein. Let's look at its features.


It is a light yellow powder, mainly composed of di- and tri-peptides, with a relative molecular weight of less than 1000 D. The main components are: crude protein> 80%, moisture <7%, ash <12%, sugar and other 1%, free amino acids <7%. Soy  bean peptide protein content is more than 80%, the amino acid composition is more reasonable and rich in content, contains 8 amino acids necessary for human body. Except for methionine, the content of other amino acids is close to or exceeds the WHO recommended standards, and has high nutritional value. At present, soybean peptides are mainly obtained through enzymatic hydrolysis. The type of protease used and the conditions under which it is used are closely related to the product composition. The physicochemical properties directly affect its functions and properties, such as processing, nutrition, and biological activity.

Soy  bean peptide

Solubility and stability

The soluble ammonia index (NSI) is above 95%, soy polypeptide is easy to dissolve water and has no residue. 

The soy protein isolate solution has poor stability, and almost all precipitates around the isoelectric point pH of 4.3. The viscosity of the soybean peptide solution is reduced, and it will not gel when heated. The viscosity of the 65% solution is only 1/4 of that of the 10% soybean protein solution, and the solubility is as high as 99% or more. The significant decrease in protein was due to the disintegration of protein multimers and the increase in ionic groups, which increased the orderliness of protein molecules and decreased hydrophobicity.

Easy to absorb

Soy peptide is generally believed that the protein in food is eventually absorbed as amino acids after being supplemented with protease. Modern biological metabolism studies have shown that human-implanted proteins are not necessarily completely absorbed in the form of free amino acids, and are more rapidly absorbed by low-molecular, dipeptide, and tripeptide than amino acids of the same composition. Because the absorption of free amino acids has a competitive inhibitory effect, such as arginine (Arg) and lysine (Lys) competing carriers during absorption, but when provided to animals in the form of small peptides, Lys absorption is no longer affected by Arg. So as to improve the utilization of amino acids. In addition, soybean polypeptides have a much lower osmotic pressure than amino acids and are easy to absorb in the body. This feature  is very suitable for use as a nutritional agent for patients and recovery periods after illness, transforming nutritional agents, digestive function decline or infant fluid food And the ideal nitrogen source fortifier in elderly food.


Hygroscopicity and moisture retention

Soy peptide is pulverized into small peptides, which changes its structure, exposes some polar amino acids, has hygroscopicity and moisture retention, softens food, adjusts the hardness of protein food, makes the product soft, elastic, and improves the taste. Apply to soy products, fish products, baked products, candy and cakes. It can also be used as moisturizing additives to produce various cosmetics or shampoos.

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