Intrinsic relationship between structural changes of different types of oyster proteins and flavor release after sous-vide treatment.

Proteins, as typical macromolecules in aquatic products, have been demonstrated to play a crucial role in flavor release. The structural modifications of water-soluble proteins (WSP), salt-soluble proteins (SSP), and alkali-soluble proteins (ALSP) in oysters after Sous Vide (SV) heating, along with their interactions with flavor compounds, were systematically investigated. More significant alterations in secondary and tertiary structures in SSP were observed compared to WSP and ALSP following SV heating, accompanied by the highest degree of hydrophobicity and aggregation. The introduction of flavor compounds further altered protein tertiary structures, with fluorescence quenching rate following the order: octanal > (E, E)-2,4-hexadienal >2,3-diethylpyrazine > (E)-2-hexenal > (E)-2-pentenal. The quenching type was primarily identified as static quenching. Higher release ratios were obtained for (E)-2-hexenal and (E)-2-pentenal when interacting with native WSP, SSP and ALSP compared to octanal, (E, E)-2,4-hexadienal, and 2,3-diethylpyrazine, suggesting the flavor release characteristics of native proteins were primarily influenced by the types of flavor compounds. Moreover, all flavor compounds exhibited significantly enhanced release ratios after SV heating, indicating protein denaturation enhances flavor liberation. This study provides key insights for flavor control in oyster processing.