Acylation of food proteins and hydrolysis by digestive enzymes: A review

The acylation of proteins involves the covalent attachment of acyl groups such as fatty acids and amino acids to both alpha- and epsilon-amino groups of the polypeptide chain. Chemical methods are currently used to covalently attach amino acids to casein via isopeptide bonds. By modifying food proteins with acylation, it is possible to increase the nutritional value of the protein judging from growth tests on rats. Enzymatic methods via transglutanaminase and human placental factor XIII for preparing protein derivatives have also been tested. In vitro hydrolysis studies using intestinal homogenates have indicated that the intestinal mucosal hydrolases efficiently cleave acylated proteins as well as E-peptide bonds. Hog intestinal aminopeptidase N, as well as N-acylpeptide hydrolase and acylase I have been found to be responsible for the biological utilization of N-acylated food proteins.