Study On Quality Changes Of Eriocheir Sinensis During Frozen Storage

In recent years,maricultured fisheries have developed rapidly in China,and taking the fresh or live sale as the main way can not adapt to the condition that the yield quickly increases.It is very important to keep the freshness by iced or frozen storage.However,a series of changes which affect seriously the freshness and edible quilities of the aquatic products still occur at low temperature storage.Using relative indexes,changes of Eriocheir Sinensis during low temperature storage—-10℃, -17℃, -24℃were studied respectively,in order that this can provide academic foundation for refreshing and processing of Eriocheir Sinensis.The glass transition temperatures of Wuxi Taihu Crab and Suzhou Shangtang Crab were determined by differential scanning calorimeter,then the storage temperatures in this experiment were selected.Results showed that:according to the thermal analysis graphs given by DSC, chose -17℃as critical point and selected -10℃,-17℃, -24℃as frozen storage temperature in this paper.Changes of Ca2+-ATPase,the contents of T-SH and A-SH,S0ANS,the salt-solubility of actomyosin,pH,trimethylamine,total volatile nitrogen, sensory properties of Eriocheir Sinensis during -10℃,-17℃and -24℃storage were analyzed so as to study the trend of each index'es change with the increase of storage time.The results indicated:the activity of Ca2+-ATPase have the characteristic of first going up then decline.The T-SH and A-SH content decreased with the increase of time.While S0ANS increased with the prolong of time.From the SDS-PAGE,the myosin heavy chain turned thin,the actin remained unchanged.This showed that myosin was more sensitive than actin.The salt-solubility of actomyosin declined with the extension of time.pH first went up then went down.TMA content raised from trace and had similar trend with TVBN.By sensory assessment,the point dropped with the increase of time.We can see from the graphs the change of myofibrillar protein and ice crystal during the frozen storage.Moreover,the kinetic model has been given according to the series of indexes.The influence of storage temperature on Eriocheir Sinensis'quality were studied.Study on the influence of glass frozen storage combined with the determination of glass transition temperature.From all the indexes,the lower frozen storage temperature,the better Eriocheir Sinensis'quality.The rate of quality declined under -10℃storage is the highest; under -24℃,its quality dropped most slowly, under -17℃,a bit worse than -24℃.