The role of oleic acid-induced aggregation and glycation modifications in peptide release from duck myofibrillar proteins.

To investigate how oleic acid-induced protein aggregation and glycation alter peptide release and distribution from myofibrillar protein (MPs), an oleic acid-MPs oxidation model was established and subjected to in vitro gastrointestinal digestion. The results showed that under mild oxidation, the looser structure of MPs promoted advanced glycation end products (AGEs) formation without significantly reducing hydrolysis. Under moderate oxidation, MPs transitioned toward dense aggregates, with increased longer peptides. Nε-carboxymethyllysine (CML) and Nε-carboxyethyllysine (CEL) levels rose by 43.82% and 38.49%, respectively. These modifications blocked trypsin recognition, significantly reducing the hydrolysis of gastrointestinal digesta (p < 0.05). Under severe oxidation, highly cross-linked aggregates formed. Limited sites preferentially produced CML, while CEL decreased markedly (p < 0.05). The combined effect of structural disruption and AGEs modification released abundant larger peptides and reduced digestibility by 11.06%. These findings confirm that protein oxidation remodels cleavage pathways and digestive product profiles through altered aggregation and AGEs modification.