Optimizing Bay Scallop (Argopecten irradians) Product Quality: Moderate Freezing as an Effective Strategy for Improving Adductor Muscle Gel Properties

The bay scallop (<i>Argopecten irradians</i>) adductor is an attractive raw material for the production of surimi-like products. The gelling properties of raw materials directly affect the quality of surimi-like products. To assess the potential of processing frozen bay scallop adductors into surimi-like products, the effects of short-term freezing treatment on the endogenous transglutaminase (TGase) activity, myofibrillar protein (MP) structure and gelling properties of bay scallop adductors were investigated during 14 days of frozen storage (-18 °C). The results showed that TGase activity in adductor muscles increased significantly during the first 7 days. After 7-14 days, the carbonyl and sulfhydryl contents of the MPs notably changed (increased then decreased). The β-turn content of the MPs increased, indicating stretching and flexibility. Surface hydrophobicity, fluorescence intensity and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis demonstrated changes in the tertiary structure of the MPs. Compared with gels from fresh samples, gels from scallop adductors frozen for 1 day presented significantly better texture characteristics (breaking force, gel strength, hardness, springiness, cohesiveness, chewiness) and higher water-holding capacity (<i>p</i> < 0.05). However, these properties significantly decreased on the 7th and 14th days (<i>p</i> < 0.05). Microstructural analysis revealed a more compact gel network from 1-day-frozen adductor muscles. These changes in TGase activity and MP structure are key factors influencing the gelling properties of frozen bay scallop adductors. This study provides new insights for improving gel properties during the frozen storage of bay scallop adductors.