冻结方式对南极磷虾品质的影响

Effects of Freezing Methods on the Quality of Antarctic Krill (EuphausiaSuperba)

以盐溶性蛋白质含量、持水率变化、感官评分、Ca2+-ATP酶活性和组织切片为指标,研究了静止空气、盐水浸渍和液氮冻结三种冻结方式对南极磷虾品质的影响。实验表明,盐水浸渍冻结条件下的冻结速率是静止空气冻结的1.39倍,样品在液氮冻结下的冻结速率达到100 cm/h。静止空气冻结后南极磷虾的持水率、盐溶性蛋白质、和感官评分最低,Ca2+-ATP酶活性降低率较高,肌肉组织结构松散,盐水浸渍冻结下的南极磷虾品质略好于静止空气冻结,液氮冻结条件下的南极磷虾的持水率、盐溶性蛋白质、和感官评分与对照组差别不显著(P>0.05),Ca2+-ATP酶活性降低率5.21%,肌肉纤维清晰、紧密、结构完整。综上所述,不同冻结方式对冻结速率影响较大,南极磷虾的品质变化与冻结速率有一定的相关性,静止空气冻结、盐水浸渍冻结后南极磷虾的品质变化较大,而液氮冻结更适合保持南极磷虾的品质。

Effects of still-air freezing,immersion freezing and liquid nitrogen freezing on the quality changes of Antarctic krill were researched by testing the indexes of salt-soluble protein,water-holding capacity（WHC）,sensory evaluation,Ca2＋-ATPase activity,and tissue section.The results indicated that the freezing rate of the krill by immersion freezing exhibited 1.39-fold higher than that of still-air freezing.And the freezing rate of the krill by liquid nitrogen freezing was 100 cm/h.By still-air freezing,the krill showed significant decrease in WHC,salt-soluble protein,Ca2＋-ATPase activity and sensory quality,and a loose muscles structure.Antarctic krill by immersion freezing showed a little better quality than that by still-air freezing,without remarkable decrease in WHC,salt-soluble protein and sensory quality（P0.05） by liquid nitrogen freezing.The reduction rate of Ca2＋-ATPase activity of the krill by immersion freezing was 5.21% and muscles fibril was compact and netlike.This research demonstrated that different freezing methods significantly affected the freezing rate of the krill.There was a correlation between the quality change and the freezing rate.The quality of Antarctic krill could be maintained better by means of liquid nitrogen freezing.