Peptide bonds cleaved by pepsin are affected by the morphology of heat-induced ovalbumin aggregates

• Published in: Food chemistry 2024-11, Vol.458, p.140260, Article 140260
• Main Authors: Suwareh, Ousmane, Causeur, David, Le Feunteun, Steven, Jardin, Julien, Briard-Bion, Valérie, Pezennec, Stéphane, Nau, Françoise
• Format: Article
• Language: English
• Subjects: Aggregation; Animals; Cleavage site; Denaturation; Digestion; Food and Nutrition; Hot Temperature; Hydrogen-Ion Concentration; Hydrolysis; In vitro digestion; Life Sciences; Ovalbumin - chemistry; Ovalbumin - metabolism; Pepsin A - chemistry; Pepsin A - metabolism; Peptides - chemistry; Protein Aggregates; Statistical analysis; Statistical model comparison
• ISSN: 0308-8146; 1873-7072; 1873-7072
• DOI: 10.1016/j.foodchem.2024.140260

The study aimed to assess the extent to which protein aggregation, and even the modality of aggregation, can affect gastric digestion, down to the nature of the hydrolyzed peptide bonds. By controlling pH and ionic strength during heating, linear or spherical ovalbumin (OVA) aggregates were prepared, then digested with pepsin. Statistical analysis characterized the peptide bonds specifically hydrolyzed versus those not hydrolyzed for a given condition, based on a detailed description of all these bonds. Aggregation limits pepsin access to buried regions of native OVA, but some cleavage sites specific to aggregates reflect specific hydrolysis pathways due to the denaturation-aggregation process. Cleavage sites specific to linear aggregates indicate greater denaturation compared to spherical aggregates, consistent with theoretical models of heat-induced aggregation of OVA. Thus, the peptides released during the gastric phase may vary depending on the aggregation modality. Precisely tuned aggregation may therefore allow subtle control of the digestion process. [Display omitted] •Pepsin's preference for specific amino acids is an essentially stable feature•Thermal aggregation mainly affects the kinetics of ovalbumin hydrolysis by pepsin•Pepsin's access to the core of ovalbumin is limited by aggregation•Aggregation allows pepsin cleavage sites never observed in native ovalbumin•Pepsinolysis of ovalbumin reveals structural differences between aggregate types