Microbial Transglutaminase Enhances Antioxidant Activity Of Yogurt Through Altering Pattern Of Water-Soluble Peptides And Increasing Release Of Amino Acids

This study compared the antioxidant capacity of yogurt with and without microbial transglutaminase treatment after milk fermentation, and investigated the correlation between antioxidant property and the water-soluble peptides and amino acids composition. Results showed that small molecular peptide fraction exhibited stronger antioxidant activity than large peptides. Microbial transglutaminase yogurt isolated fraction had stronger antioxidant capacity than that from the control. Microbial transglutaminase altered the peptides composition, and resulted in higher amount of small molecular peptides (<1.5kDa) mainly consisting of -casein-derived peptides in yogurt. The dominant peptides sequences (IAKYI, IAKYIPI, IAKYIPIQY, PYYAK and NQFLPYPYYAK) in the treated yogurt were different from those in the control (PYPQ, VLPVPQKAVPYPQ, PVPQKAVPYPQ and VLSRYPSYGLN). Microbial transglutaminase improved the composition and concentration of amino acids in yogurt.