The extent of ovalbumin in vitro digestion and the nature of generated peptides are modulated by the morphology of protein aggregates

• Aggregated ovalbumin is more extensively digested compared with native ovalbumin.
• OVA aggregation rendered specific peptide bonds accessible to digestive proteases.
• OVA aggregate morphology is modified by heating under different pH conditions.
• The extent and the nature of digestion are modulated by aggregate morphologies.

The impact of heat-induced aggregation on the extent of ovalbumin digestion and the nature of peptides released was investigated using an in vitro digestion model. The extent of hydrolysis, estimated by the disappearance of intact ovalbumin and the appearance of soluble peptides, was greater for the linear aggregates as compared to the spherical aggregates. The latter result may be due to differences in the surface area to volume ratio of the aggregates, or the degree of unfolding of the proteins during aggregate preparation. Peptide identification using LC–MS/MS highlighted that ovalbumin aggregation rendered a number of peptide bonds accessible to digestive proteases which were not accessible in native ovalbumin. Moreover, the peptide bonds that were cleaved appeared to be specific depending on the morphology of the aggregates. This work illustrates the links existing between food structure and their breakdown during the digestive process. Such quantitative and qualitative differences may have important nutritional consequences.