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

Abstract

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 H 2 O 2 . The increased content in a free sulfhydryl group and surface hydrophobicity indicated that oxidation treatment with 1 mM H 2 O 2 induced unfolding of MP. Reducing and nonreducing SDS−PAGE results suggested that 10 mM H 2 O 2 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 H 2 O 2 ) facilitated the release of peptide in the rod portion (S2) of myosin, whereas excessive oxidation (10 mM H 2 O 2 ) 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.

Effects of Baking and Frying on the Protein Oxidation of Wheat Dough

“…The overall performance was irregular curl, α-helix toward β-sheet, and β-turn direction change. Yin et al [47] proved that hydrogen peroxide-induced protein oxidation significantly increased the proportion of β-sheet and β-turn, consistent with our results. The secondary structure of proteins may be affected by various forces such as covalent cross-linking, electrostatic interaction, and hydrophobic interaction.…”

“…In our study, with the increased baking and frying time and temperature, the decrease in protein digestibility may be caused by protein oxidation. It has been shown that the recognition sites of pepsin are mainly hydrophobic amino acids [47], but with the oxidation of protein and the aggregation of macromolecular substances, the enzyme cannot recognize the hydrolysis point. A study has shown that linoleic acid induces soybean protein oxidation, and it was found that under low oxidation conditions, the Different lowercase letters indicate significant differences between different baking and frying times and temperatures; the markers "*" and "**" represent the significant differences (p < 0.05) and highly significant differences (p < 0.01) vs. the control group.…”

Improvement of oxidized myofibrillar protein gel properties by black rice extract

“…In the gel sample supplemented with DTT in Fig. 6 b, light chains of myofibrils with ∼30 KDa appeared ( Yin, Xing, & Zhang, 2023 ), which is because DTT breaks the —S—S— in MP gel. In addition, protein aggregation occurred at the top of the concentrated gel in Fig.…”