Effect of transglutaminase on taste characteristics of pea protein hydrolysates through altering the composition of amino acids and peptides

This study investigated the effects of transglutaminase (TGase) treatment on the taste profiles and peptide compositions of pea protein isolate hydrolysates (PPIH) produced by Flavourzyme and protease 11,039. TGase significantly increased umami intensity by 50% and dramatically decreased bitterness by 40% in PPIH. While protein recovery, degree of hydrolysis, and peptide nitrogen percentage remained unaffected, TGase altered the relative proportions of taste compounds. This was evident through increased levels of umami, hydrophilic, and sweet-bitter amino acids in non-free amino acids, indicating the formation of peptides with umami potential. UPLC-MS/MS analysis confirmed that TGase facilitated the generation of longer peptides with higher umami potential compared to the short peptides in untreated PPIH. Simultaneously, the reduction in bitter components and the generation of umami substances contributed to the decrease in bitterness. Receptor-peptide docking studies confirmed that the newly formed peptides had higher binding affinities. Overall, TGase modification led to a shift in the substance profiles of PPIH, resulting in the creation of peptides with enhanced umami characteristics. These findings demonstrate the potential of combining TGase treatment with enzymatic hydrolysis to modify taste properties and develop flavorful plant-based protein ingredients.