Ellman's法测定鲜、冻鱼糜的巯基含量

Determination of Sulfhydryl Groups in Fresh and Frozen Surimi by Ellman’s Method

鱼糜在冷藏过程中容易发生变性从而影响其凝胶强度。为探究鲜、冻鱼糜变性程度,本文以鲜、冻鱼糜为原料,以巯基含量作为衡量蛋白变性指标,采用Ellman’s法对鱼糜巯基含量进行测定。通过单因素条件优化试验,得到总巯基最佳测定条件为含EDTA的稀释液,DTNB的添加量为100μL,反应时间为45 min,反应温度为25℃;游离巯基最佳测定条件为含EDTA的稀释液,DTNB的添加量为200μL,反应时间为60 min,反应温度为40℃。使用最优条件对鲜、冻鱼糜进行巯基含量测定,结果显示鲜鱼糜的总巯基和游离巯基的含量均高于冻鱼糜,这也在一定程度上证明了冻藏会导致鱼糜部分蛋白变性。

Surimi is prone to denaturation during refrigeration which affects the gel strength.In order to explore the denaturation degree of fresh and frozen surimi,this paper used fresh and frozen surimi as raw materials,and measured the sulfhydryl content of surimi by Ellman’s method.Bying single factor condition optimization test,the optimum conditions for the determination of total sulfhydryl groups were as follows:the diluent containing EDTA,the addition amount of DTNB was 100μL,the reaction time was 45 min,and the reaction temperature was 25℃.The optimal conditions for the determination of free sulfhydryl group were as follows:the diluent containing EDTA,the addition amount of DTNB was 200μL,the reaction time was 60 min and the reaction temperature was 40℃.The optimum conditions were used to determine the content of sulfhydryl group in fresh and frozen surimi.The results showed that the content of total and free sulfhydryl group in fresh surimi was higher than that in frozen surimi,which also proved that frozen storage would lead to degeneration of surimi to some extent.