Characterization of peptides released from frozen-then-aged beef after digestion in an in vitro infant gastrointestinal model

This study investigated whether the freezing-then-aging treatment of beef affects protein digestibility and release of potentially bioactive peptides using an in vitro infant digestion model. After 28 days of storage, aged-only (AO) and frozen-then-aged (FA) beef exhibited higher α-amino group contents in the 10% trichloroacetic acid-soluble fraction compared to day 0 (P < 0.05). Following in vitro digestion in the infant model, FA showed higher contents of α-amino groups and smaller proteins (<3 and 1 kDa) than day 0 and AO (P < 0.05). Relative contributions of myofibrillar, sarcoplasmic, and stromal proteins to the bioactive peptides released from AO and FA differed from those of day 0. In addition, FA exhibited a higher proportion of potential bioactive peptide sequences. Overall, freezing-then-aging treatment can enhance the potential health benefits of beef to be used as a protein source for complementary foods.