南极磷虾酶解工艺优化及酶解产物对牡蛎肉的冷冻保护作用

为了开发安全高效的无磷抗冻剂,本研究以南极磷虾为原料制备酶解产物对其进行冷冻保护作用评价,为开发新型抗冻剂提供基础数据。以水解度为指标,对南极磷虾进行酶解,从4种蛋白酶中筛选得到碱性蛋白酶作为实验用酶,在单因素实验的基础上结合正交试验对酶解工艺进行了优化;并以解冻失水率、盐溶性蛋白含量、总巯基含量、Ca2+-ATPase酶活力为指标,考察了南极磷虾酶解产物对牡蛎肉的冷冻保护作用。结果表明,用碱性蛋白酶酶解南极磷虾的最佳条件为温度为55℃,酶解pH为8.5,加酶量2.6%,酶解时间为5 h;在此工艺参数下南极磷虾酶解产物相对分子质量主要分布在100~5500 Da,占总酶解产物的79.69%。南极磷虾酶解产物可以抑制牡蛎冻藏后失水,延缓盐溶性蛋白、Ca2+-ATPase酶活力、总巯基含量下降,其作用效果优于含磷抗冻剂。因此,南极磷虾酶解产物具有冷冻保护活性,可进一步对其进行分离鉴定研究。

Optimization of Enzymatic Hydrolysis Process of Antarctic Krill and Cryoprotective Effect of Enzymatic Hydrolysates on Oyster Meat

In order to develop a safe and efficient non-phosphorus antifreeze agent,enzymatic hydrolysates of Antarctic krill were prepared to evaluate their cryoprotective effects,providing basic data for the development of new antifreeze agents.The alkaline protease was screened from the four proteases as experimental enzymes,and the enzymatic hydrolysis process was optimized by single factor experiment and orthogonal experiment. The freezing protection of oyster meat by enzymatic hydrolysates of Antarctic krill was studied with the indexes of the water loss rate,salt-soluble protein content,total sulfhydryl group content and Ca2+-ATPase activity.The results showed that the optimum conditions for enzymatic hydrolysis of Antarctic krill by alkaline protease were as follows:Temperature 55℃,pH8.5,enzyme dosage 2.6%,enzymatic hydrolysis time 5 h. Under these conditions,the relative molecular weight of enzymatic hydrolysates of Antarctic krill mainly distributed in the range of 100~5500 Da,accounting for 79.69% of the total enzymatic hydrolysates. The enzymatic hydrolysate of Antarctic krill could inhibit the loss of water after freezing storage,retard the decrease of salt-soluble protein content,Ca2+-ATPase activity and total sulfhydryl content,and its effect was better than that of phosphorus-containing antifreeze agent.Therefore,the enzymatic hydrolysate of Antarctic krill had freezing protection activity,which could be further separated and identified.