Changes in the Amino Acid Composition of Gelatin After Treatment of Bovine Collagen with Enzyme Preparations

Recently, increased attention has been paid to the study of the amino acid (AA) composition of gelatins, which is associated with the quality of the corresponding gels as intermediates for human and animal nutrition. In a brief review, a modification of the general method of acid extraction of collagens for the preparation of gelatins using enzymes (such as papain, actinidin, and others) is considered and the corresponding changes in the amino acid composition of gelatins are discussed. It is clear that there are changes in the content of glycine in gelatins from any collagens, but in all cases the content of glycine is about a third of the content of all amino acids (as in the original collagens). It is important that the content of imino acids (the sum of proline and hydroxyproline, which largely determines the properties of gels) in gelatins from any collagens with the use of all the studied enzymes is much higher than without them. In addition, the content of imino acids in gelatin from the bovine skin of cows with the use of any enzymes is significantly higher than in gelatins from the skin of pigs and fish. This also holds true for other key proteinogenic AAs. The reverse trend is observed only for a few AAs: serine, threonine, tyrosine, and phenylalanine, whose content is low in gelatins from any collagens.

Automated summary

Recently, there has been increased attention on the study of the amino acid composition of gelatins and its relation to the quality of gels. The use of enzymes in the acid extraction of collagens to prepare gelatins brings about changes in the amino acid composition. The content of glycine in gelatins varies, but it is generally about one-third of the total amino acid content. The use of enzymes significantly increases the content of imino acids in gelatins, which is important for the gel properties. The content of imino acids in gelatin from bovine skin is higher than that from pig and fish skin, as well as other key proteinogenic amino acids. Only a few amino acids, such as serine, threonine, tyrosine, and phenylalanine, have low content in gelatins from any collagens.