Abstract: To investigate the effect of pre-cooking treatment on the quality of swimming crab (Portunus trituberculatus) meat during frozen storage, the differences in the quality of group C (control without any treatment), group H-F (heating followed by frozen storage) and group F-H (frozen storage followed by heating) during 180 d storage at −20 ℃ were evaluated in terms of their color difference, water-holding capacity (WHC), pH, total volatile base nitrogen (TVB-N) content, total viable count (TVC), and protein composition and microstructure. The results showed that the whiteness and WHC of the three groups decreased with storage time. The pH of group C decreased first and then increased, while the pH of the other two groups showed the opposite trend and then remained steady. The TVB-N content and TVC of all groups showed an overall upward trend. The TVB-N content and TVC of group H-F were (21.12 ± 0.58) mg/100 g and (4.03 ± 0.17) (lg(CFU/g)) after 180 d, respectively, which were significantly lower than those of group F-H. The microstructure of crab muscle in group C changed from clear and ordered to fuzzy and disordered during the frozen storage process, while pre-cooked crab meat maintained a better morphology. Besides, the results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) suggested that crab meat proteins in the three groups were degraded to different degrees during storage, which was more pronounced in group F-H than in group H-F. Therefore, pre-cooking treatment could efficiently reduce the quality deterioration of crab meat during frozen storage, which could provide a reference for subsequent research to improve the frozen storage quality of P. trituberculatus.

Key words: Portunus trituberculatus; pre-cooking treatment; frozen storage; muscle quality; microstructure