Abstract:In this study, the effects of ultra-low temperature freezing and frozen storage on the quality of mussels during frozen storage were explored by taking the freezing method and frozen storage temperature as variables. During the 6-week freezing process, compared with the slow freezing in the refrigerator and the freezing at -20 ℃, the mussels were quickly frozen in liquid nitrogen and thawed at -30 ℃, resulting in a loss of 22.58%, a higher moisture content (76.61%) as compared with the other groups, and the best sensory scoring while maintaining good elasticity (0.52 mm) and chewiness (5.64 mJ). During the frozen storage period, the TVB-N value and total bacterial count of the mussels continued to increase, whilst the pH continued to decrease. After rapid freezing in liquid nitrogen and frozen storage below -30 ℃ , the TVB-N value of mussels was 12.2 mg/100 g, and the total bacterial count was 32 CFU/g, which were significantly lower than those of the other three groups (P<0.05). The pH value (7.32) and color L* value (66.18) of mussels were higher than those of the other three groups. Compared with the other groups, the Ca2+-ATPase (345.21 IU/L) activity of the myofibrillar protein in the mussels frozen at -20 ℃ after rapid freezing in liquid nitrogen was the highest, with higher elasticity (0.59 mm) and chewiness (6.86 mJ). In summary, using liquid nitrogen for quick freezing of mussels can effectively improve the quality of frozen mussels, and a lower storage temperatures can improve the quality of frozen mussels to a certain extent, which will provide theoretical support for ultra-low temperature preservation of mussels.
