Effect of desalination-related pH shift on whey protein structure and digestion: Insights from spectroscopy,...

The digestibility and bioactivity of whey protein (WP) are essential to its function as a dietary supplement. However, the impact of pH changes during desalination on WP structure, digestibility, and bioactive peptide formation mechanisms remains uncertain. This study examined different pH treatments on WP in vitro digestion using spectroscopy, molecular dynamics (MD), and peptideomics. The results show that acidic pH and pH shift treatments significantly increased WP hydrolysis degree (11.27 % and 13.72 %, p < 0.05), while reducing molecular weight and antigenicity of digestion products. Spectroscopy analysis revealed pH-induced changes in WP secondary and tertiary structures, increasing enzymatic accessibility to cleavage sites. Peptideomics and MD simulations further confirmed that pH treatments induced conformational changes in α-lactalbumin and β-lactoglobulin, increased post-digestive bioactive peptide levels, and decreased β-lactoglobulin allergenicity. This study elucidates how pH regulation improves WP digestibility, offering theoretical and technical foundations for optimizing WP processing and developing low-allergenic, high-bioactivity functional foods.