真空包装草鱼片低温贮藏后微观结构及理化性质的变化

为研究真空包装草鱼片在低温条件下的变化,将真空包装草鱼片分别于-18、0、4、10℃贮藏15 d,以贮藏期间K值(ATP分解指数)的变化来评价其化学变化。结果表明:在0、4、10℃下贮藏15 d后,草鱼肌纤维间的空隙变大,由于鱼肉内水的结晶,在-18℃下肌纤维间的空隙达到最大(约100μm);随着贮藏时间的延长,鱼片的持水能力显著下降,-18℃下贮藏鱼片的持水能力最低,0、4℃贮藏鱼片的持水能力高于10℃贮藏鱼片;于较高温度(0、4、10℃)贮藏后,鱼肉的亮度值(L*)、红绿值(a*)和黄蓝值(b*)均较高,在-18℃低温贮藏后鱼肉的亮度值增加;随贮藏时间的延长,鱼片颜色(色差仪分析结果)趋向于红色值和黄色值增大;在-18℃贮藏15 d后,鱼片仍然新鲜,但质构变差。

Microstructure, chemical and physical changes of vacuum-packed grass carp(Ctenopharyngodon idella) fillets stored in low temperature

This study was carried out to evaluate the microstructure,chemical and physical changes of vacuum-packed grass carp(Ctenopharyngodon idella) fillet stored in low temperature(-18,0,4,10 ℃) during 15 d of storage.The chemical changes were demonstrated by significant increase of K-value during storage.Chilling temperature,higher temperature and longer storage time gave bigger spaces between the muscle fibers,while freezing temperature gave the biggest gapping due to ice crystallization between muscle fibers.Water holding capacity(WHC) was decreased significantly after storage with frozen fish having the smallest WHC.0 and 4 ℃ storage had higher WHC than 10 ℃ storage.L*,a* and b* value were higher at higher temperature storage and longer storage time,indicating that the fish were lighter,more reddish and yellowish at the end of storage.Only fish stored in frozen temperature(-18 ℃) were considered still fresh until 15 d,but had poor texture quality.