内源性转谷氨酰胺酶对淡水鱼鱼糜凝胶化的影响

Effect of endogenous transglutaminase on setting of surimi from freshwater fishes

研究罗非鱼、鳙鱼、鲮鱼3种淡水鱼鱼糜在25℃和40℃的凝胶化特性,并通过SDS-聚丙烯酰胺凝胶电泳(SDS-PAGE)、内源性转谷氨酰胺酶(TGase)活性的检测及研究添加TGase激活剂(CaCl2)和抑制剂(EDTA,NH4Cl)对其凝胶化特性的影响,探讨内源性TGase在淡水鱼鱼糜凝胶中的作用。实验结果表明,经过25℃或40℃凝胶化后,3种鱼糜的凝胶强度均显著得到提高。SDS-PAGE图谱显示,经过凝胶化后,3种鱼糜凝胶的肌球蛋白重链(MHC)带的强度均减弱,说明鱼糜的MHC在内源性TGase的作用下发生了交联作用。罗非鱼鱼糜和鳙鱼鱼糜适合在40℃凝胶化,而鲮鱼鱼糜适合在25℃凝胶化,这与其内源性TGase活性是一致的。添加激活剂CaCl2后,3种鱼糜的凝胶强度都显著增加,与MHC带强度减弱相一致;而添加抑制剂EDTA、NH4Cl后,3种鱼糜的凝胶强度都显著降低,与MHC带强度增加也相一致。上述结果表明,淡水鱼鱼糜的内源性TGase在其凝胶化过程中起着很重要的作用。

The setting properties at 25 ℃ and 40 ℃ of freshwater fish surimi from three species, i.e. tilapia, bighead carp and dace were studied. SDS-polyacrylamide gel electropHoresis（SDS-PAGE）, the test of the activity of endogenous transglutaminase（TGase）and the effect of TGase activator（calcium chloride）and inhibitors （EDTA, ammonium chloride）on the setting properties of the surimi were carded out to investigate the function of TGase during setting. The results showed the gel strength of the surimi gels from three species made by setting at 25 ℃ or 40 ℃could be increased markedly. SDS-PAGE declared the intensity of the myosin heavy chain （MHC）of the setting gels all decreased suggesting the cross-linking of MHC catalyzed by endogenous TGase during setting. The optimal setting temperature of tilapia and bighead carp surimi was found to be 40 ℃, while that of dace surimi was 25 ℃, which was coincided with the activity of endogenous TGase. The gel strength of the surimi gels from three species was considerably elevated with the addition of calcium chloride, which was coincided with the decrease of the intensity of their MHCs. On the other hand, the gel strength was decreased markedly with the addition of EDTA and ammonium chloride, which was in agreement with the increase of the intensity of their MHCs. The above results confirmed that endogenous TGase played an important role during the setting of the freshwater fish surimi.