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)

摘要:

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。

Abstract:

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 (P>0.05) 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.