Insights from structural characterization for understanding isolation and impact of roasting on allergenic potential...

A systematic extraction protocol involving multiple oil body washing with buffers of NaHCO₃ (pH 10), NaCl, and urea was investigated, and the enrichment of α-helix-rich hydrophobic proteins were monitored by the spectroscopic techniques, while the isolated proteins were identified as oleosin with a relative content of 81.05 %. Dot-blot analysis revealed the allergenicity was enhanced at 150 °C compared to the unroasted state, followed by a decline at 180 °C. SDS-PAGE and size exclusion chromatography showed the formation of higher molecular weight aggregates during roasting, while spectroscopy methods indicated a complex process of protein unfolding, folding, and re-unfolding, along with secondary structure modifications. Molecular dynamics simulations indicated structural alterations and flexibility changes, especially at the N- and C-terminal domains of oleosins, within the phospholipid membrane. Protein-protein docking demonstrated the strong self-association of oleosins after roasting. This study offers theoretical reference for deeper understanding of the structural alterations of sesame oleosins post-roasting.