Moderate Protein Oxidation Improves Bovine Myofibril Digestibility by Releasing Peptides in the S2 Region of Myosin: A Peptidomics Perspective

This study aimed to investigate the influence of protein oxidation on the digestive properties of beef myofibrillar protein (MP). MP was treated with a hydroxyl radical-generating system containing various concentrations of H2O2. The increased content in a free sulfhydryl group and surface hydrophobicity indicated that oxidation treatment with 1 mM H2O2 induced unfolding of MP. Reducing and nonreducing SDS-PAGE results suggested that 10 mM H2O2 oxidation treatment resulted in aggregation of MP; meanwhile, the disulfide bond was the major covalent bond involved in aggregation. Peptidomics showed that peptides in the digestion products of MP were mainly derived from myosin tail. Moderate oxidation (1 mM H2O2) facilitated the release of peptide in the rod portion (S2) of myosin, whereas excessive oxidation (10 mM H2O2) inhibited peptide release in the light meromyosin region. This work presents insightful information for the crucial impact of oxidation on meat protein digestibility from the peptidomics perspective.