中文摘要：

以草鱼内脏为原料,脱脂离心制备蛋白质粗提液,用SDS-PAGE方法测定蛋白质分子质量,然后以制备的草鱼内脏蛋白质为底物,比较研究木瓜蛋白酶、碱性蛋白酶、风味蛋白酶、胃蛋白酶、胰蛋白酶和中性蛋白酶的水解特性。结果表明：草鱼内脏蛋白质分子质量分别约为32.4、13.2、2.8kD。6种酶解液中氨基酸含量在前6h随着时间的延长迅速增加,后趋于平稳;风味蛋白酶的氨态氮含量最高,碱性蛋白酶与中性蛋白酶之间差异不显著,其他各种蛋白酶两两之间差异都显著。而胰蛋白酶、胃蛋白酶、中性蛋白酶、木瓜蛋白酶、风味蛋白酶多肽含量在酶解6h达到最大值,碱性蛋白酶在酶解9h时达到最大值,木瓜蛋白酶多肽含量最高,而风味蛋白酶的最低。随着酶解的不断进行,酶解液的呈味效果不断发生着变化,酶解液的呈味特性随着氨基酸和多肽的释放,鲜味逐渐明显,以感官评价为指标风味蛋白酶的鲜味最强,6种蛋白酶互相之间差异都显著。

英文摘要：

Crude protein extract was prepared from defatted grass carp viscera.Molecular weigth determination of protein components in the crude extract were performed using SDS-PAGE.Papain,alcalase,flavorzyme,pepsin,trypsin,and neutral protease were compared for differences in their hydrolysis characteristics using the crude extract as a susbtrate.Proteins with molecular weigth of 32.4,13.2 kD and 2.8 kD were detected in the crude extract.For each enzymatic hydrolysate,the content of amino acids promptly increased with hydorlysis time up to 6 h followed by a stable trend.The highest amino nitrogen content was found in the flavorzyme hydrolysate,and a signifciant differene in this indicator was observed between the hdyrolysates prepared with all proteases except alcalase and neutral protease.The maximum polypeptide content was obtained when the hydrolysis time was 6 h with trypsin,papain,neutral protease,pepsin,flavorzyme and 9 h with alcalase;the papain hydrolysate had the highest polypeptide content,whereas the lowest polypeptide content was found in the flavorzyme hydrolysate.The taste of hydrolysates changed continueously as hydrolysis proceeded.Moreover,amino acids and polypeptides responsible for umami were gradually released.The flavorzyme hydrolysate had the strongest umami based on sensory evaluation.We also found significant umami differences among all the enzymatic hydrolysates.