Investigating the impact of ovalbumin aggregate morphology on in vitro ovalbumin digestion using label-free quantitative peptidomics and multivariate data analysis

- The morphology of OVA aggregates governs the amount and type of peptides released.
- Peptic and chymotryptic cleavages are favored for OVA aggregates.
- Tryptic cleavages are favored for spherical-agglomerated OVA aggregates.
- The peptide release from flexible regions of native OVA is favored by aggregation.
- The peptide release from the surface of native OVA is favored for linear aggregates.

This study aimed to investigate how food structure, in the form of different ovalbumin aggregate morphologies, impacted the proteolysis of ovalbumin using an in vitro model that simulated digestion in the adult gastrointestinal tract. Four different aggregate morphologies were prepared by heating ovalbumin solution using different combinations of pH and ionic strength. Quantitative peptidomics (label-free) and multivariate data analysis of the resulting in vitro digests were performed. The 593 identified peptides were distributed in 6 homogeneous clusters based on the relative amount of peptide release from the different aggregate morphologies. Each cluster gathered peptides with common physicochemical characteristics. The results suggest that peptic and chymotryptic cleavages were favored by aggregation regardless of the aggregate morphology, while tryptic cleavages were favored when ovalbumin aggregates were spherical-agglomerated. It is notable that even after extensive digestion, the initial aggregate morphology influenced the amount of each peptide released.