微小杆菌属SWJS2蛋白酶对鱼肉酶解特性的研究

Enzymatic Hydrolysis of Fish Proteins using Protease Produced by Exiguobacterium sp. SWJS2

本文以凤尾鱼、草鱼为原料,研究了本实验室新筛选的微小杆菌属SWJS2所产蛋白酶对凤尾鱼和草鱼蛋白的酶解特性。结果表明:微小杆菌属SWJS2蛋白酶对凤尾鱼和草鱼的最适酶解温度分别为40℃和45℃。微小杆菌属SWJS2蛋白酶对凤尾鱼的酶解效果优于木瓜蛋白酶,酶解12 h时蛋白回收率为72.64%,水解度达21.38%,ORAC值与还原力均高于木瓜蛋白酶的酶解产物。微小杆菌属SWJS2蛋白酶酶解草鱼的蛋白回收率及抗氧化性能则不及木瓜蛋白酶,但水解度较高。微小杆菌属SWJS2蛋白酶对两种鱼肉的酶解产物中游离氨基酸组成与6种商业蛋白酶有明显差异,亮氨酸、丙氨酸、缬氨酸、苯丙氨酸、异亮氨酸含量显著高于商业酶,而精氨酸、天冬氨酸、苏氨酸、丝氨酸、天冬酰胺等的含量较低。说明其优先酶切位点与6种商业蛋白酶有较明显的差异。

The hydrolysis characteristics of the protease produced by a new isolated Exiguobacterium sp. SWJS2 on Coilia mystus and Grass carp were studied. The results showed that the optimal hydrolysis temperature of Exiguobacterium sp. SWJS2 protease （EP） was 40 ℃ for Coilia mystus and 45 ℃ for Grass carp. The enzymatic hydrolysis effect of EP on Coilia mystus was better than that of papain. The protein recovery was 72.64% and the degree of hydrolysis was 21.38% after 12 h. The ORAC value and reducing power were higher than the hydrolysates by papain. For Grass carp hydrolysates by EP, the protein recovery and antioxidant activities were poorer than papain hydrolysates, but the degree of hydrolysis was much higher. The flee amino acids compositions of Coilia mystus and Grass carp hydrolysates by EP were quite different from those of six commercial proteases. The contents of Leu, Ala, Val, Phe and Ile were much higher in EP hydrolysates, while the contents of Arg, Asp, Thr, Ser and Asn were rather low, which reflected that the prior cleavage site of EP had obvious differences from the six commercial proteases.