Abstract: This study analyzed the effects of four combined processing methods, namely boiling (W), steaming (G), microwave (M), and fresh (F)) each followed by deep frying (denoted as WF, GF, MF, and FF, respectively) on the color, texture, nutritional components, water distribution, protein secondary structure, thermal stability, microstructure, and volatile substances of seasoned scallop meat. The results showed that boiled scallop had a loose and porous structure, which facilitated the penetration of oil into the core area through the pores. Under the internal steam pressure generated by the batter coating, the hardness ((736.32 ± 14.73) N) of the MF group was higher than that of the GF and WF groups, and its chewiness was significantly lower than that of the GF and WF groups (P < 0.05). The MF group showed a stronger binding capacity for immobilized water and free water, and microstructural observations revealed that protein aggregates were reconstructed into a blocky structure. The GF group exhibited more pronounced myofibrillar protein aggregation and larger pores on the surface due to uneven heating during steaming, which led to greater oil penetration during frying. Its α-helix content was significantly lower than that of the WF and MF groups (P < 0.05). The FF group had the longest heating time, resulting in more severe protein oxidation and cross-linking. Its relative content of α-helix, (33.51 ± 3.43)%, was significantly lower, while its enthalpy of aggregation (344.70 J/g) was significantly higher than that of the other treatment groups (P < 0.05). WF performed best in retaining volatile substances, retaining key volatile components such as hexanal (grass-like aroma), 1-octen-3-ol (mushroom-like and earthy aroma), and 4-isopropylbenzaldehyde to the greatest extent. Therefore, WF, which retained the highest number of volatile substances and showed no obvious disadvantages in other aspects, was selected as the preferred combined processing method for seasoned scallop meat.

Key words: scallops; combined processing; volatile substances; low-field nuclear magnetic resonance; protein secondary structure