Effect of protease reaction conditions on volatile compounds generated in Maillard reaction products from soy protein hydrolysates

Maillard reaction products (MRPs) produced by heating protease-catalyzed soy protein hydrolysates (SPHs) with cysteine and ribose can generate meat-like flavors. However, the impact of protease reaction conditions on the volatile compound composition of MRPs has not been thoroughly investigated. In this study, seven SPHs were prepared using two proteases, flavourzyme and trypsin, over reaction times of 10, 120, and 1440 min. The volatile compound compositions, including sulfur-containing compounds, aldehydes, pyrazines, and furans, of the seven SPHs and the corresponding seven MRPs varied according to the protease reaction conditions and the Maillard reaction. Differences in pH, free amino acid composition, and peptide composition were responsible for these variations. Notably, soy-derived peptides containing unique cysteine sequences, such as PGCPST, DETICT, ECQIQK, and HCQR, were significantly reduced during the Maillard reaction, suggesting that these sequences may serve as precursors to volatile compounds.