Insights into differences in oxidation and interaction of main components in porcine and bovine milk during refrigerated storage

Oxidation and interactions of components in porcine milk (PM) and bovine milk (BM) during 6-day storage at 4 °C were investigated. Compared to BM, PM exhibited higher levels of lipid oxidation products, protein carbonyl and surface hydrophobicity (P < 0.05), with protein aggregation, indicating PM underwent more extensive lipid and protein oxidation. In contrast, BM showed higher 3-deoxyglucosone (3-DG) and D-glucosone (GLO) accumulation, greater sulfhydryl loss, enhanced fluorescence, and fluctuating particle size, suggesting carbohydrate oxidation and glycation reaction. Orthogonal projection to latent structures discriminant analysis identified surface hydrophobicity, thiobarbituric acid-reactive substances (TBARS), particle size and sulfhydryl groups as discriminators of PM and BM oxidation states. TBARS in PM correlated with particle size, carbonyl and sulfhydryl groups (P < 0.05), whereas BM surface hydrophobicity correlated with 3-DG and GLO contents (P < 0.05). Thus, lipid oxidation in PM was associated with protein changes, whereas in BM such changes paralleled glycation driven by carbohydrate oxidation and glycation reaction.