**4. Conclusion**

The results of studies of the chemical composition, physicochemical characteristics of proteins, and functional properties of dry wheat gluten, its components, protein concentrates from wheat bran, and their granulometric fractions have shown that it is advisable to regulate the quality indices of protein products with the aim of improving them and taking into account the revealed regularities. A high correlation positive dependence was established for the solubility of wheat gluten proteins, protein concentrates from wheat bran and their fractions with the amount of albumins and globulins, the sum of nonpolar amino acids (gluten, gliadin, soluble glutenin), and a negative correlation with gliadin gluten. With the indices of thiol metabolism, the relationship between solubility and WBA is not revealed.

For WBC of protein products, the reverse dependence on the sum of the polar amino acids of both fractions of glutenin is typical; for FBA, it is a direct relationship with the sum of gluten proteins and polar amino acids in gliadin and whole gluten and the inverse relationship was observed for the sum of nonpolar amino acids in the alcohol-soluble fraction. The lower the protein aggregation coefficient, hence, the less degree of hydrophobic interactions, less than -SH-groups, but more -S-S-bonds in proteins, the higher the FBA.

FEA positively correlated with the amount of glutenin and insoluble residue in proteins from wheat bran and the sum of nonpolar amino acids in gluten, gliadin. A negative relationship is established for the sum of polar amino acids, as whole gluten, and all its fractions. The higher the degree of hydrophobic interactions in protein products and the less disulfide bonds in them, the ability to emulsify fat and stabilize the emulsion is higher.

The average correlation dependence was revealed for FC and the mass fraction of protein for all types of protein products studied. The FC of gluten proteins positively correlated with the sum of nonpolar amino acids of gliadin, soluble, insoluble glutenin, and polar amino acids of insoluble glutenin. The sum of two kinds of amino acids also positively influenced the FC of other protein products. The higher the mass fraction of albumins, globulins, and gliadin in gluten, the more FC products are. As for FEA protein products from wheat bran, it was found that the higher the content of SH groups and the lower the number of S-S bonds in protein products, the more FC protein products are higher.

Consequently, the main functional properties of the protein products studied from wheat are interrelated with the protein mass fraction, the features of the fractional, amino acid composition of proteins, the number of covalent disulfide bonds, sulfhydryl groups, and non-covalent (hydrophobic) interactions. Thus, in order to predict the high and stable functional properties of protein products from wheat for production or their modification, it is advisable to take into account the patterns of interrelation of these properties with the chemical composition and the physicochemical properties of their proteins.
