Microwave Processing Alters Milk Protein Digestion and Peptide Release: Insights from Peptidomics and Bioactivity Evaluation

Abstract This study compared microwave (MW) and conventional thermal (CT) processing at 70 °C for 20 s and 135 °C for 5 s, simulating pasteurization and ultrahigh-temperature (UHT) processing, respectively, to investigate their effects on milk protein digestion and functionality. MW treatment reduced heat-induced aggregation and improved protease digestibility. Peptidomic analysis revealed distinct peptide profiles, with MW-UHT generating more low-molecular-weight peptides and promoting selective cleavage within functional regions of caseins and favoring the generation of bioactive peptide sequences during digestion. Importantly, cell-based assays demonstrated that digests from MW-treated milk exerted stronger anti-inflammatory effects in LPS-stimulated RAW264.7 macrophages than CT counterparts. These findings provide experimental evidence that MW processing not only reshapes digestive peptide release but also better preserves the biofunctional potential of milk proteins.