Effects of thawing methods on the biochemical properties and microstructure of pre-rigor frozen scallop striated adductor muscle

Postmortem biochemical properties (pH, salt solubility, Ca2+-ATPase activity, ATP-related compounds) and microstructural changes in the striated adductor muscle of pre-rigor frozen Japanese scallops (Patinopecten yessoensis) were studied after thawing and during storage at 4 degrees C. Four thawing methods were used: running water (18 degrees C, R); ice-water (0 degrees C, I); air (4 degrees C, A) and ice-saltwater (-2 degrees C, S). The pH values and salt solubility of R group were lower than the other three thawing groups while I group was highest after thawing. However, no significant difference (P < 0.05) in Ca2+-ATPase activity were detected among 4 groups. The microstructure results indicated that the structure of I group was close to that of fresh scallop. Moreover, ATP decomposition rate was the slowest. Therefore, ice-water thawing is the best method because it induced the least changes in the biochemical properties and microstructures of scallop adductor muscle.