酸性蛋白酶对高盐稀态酱油发酵的影响

以高盐稀态发酵酱油为研究对象，以未添加酸性蛋白酶的样品为对照组（K），在酱油发酵初期（0 d）添加酸性蛋白酶（1‰）的样品为实验组（S），通过分析发酵过程（1～62 d）中酸性和中性蛋白酶活力、pH、总酸含量、氨基酸态氨含量和游离氨基酸含量的变化及生酱油的呈味氨基酸含量，考察添加外源酸性蛋白酶对酱油发酵的影响。结果表明，S组的酸性蛋白酶和中性蛋白酶活力分别为K组的2.9倍和2.1倍。发酵结束时，与K组相比，S组酱油的pH下降至4.50、总酸、氨基酸态氮含量分别增加36.71%、16.49%；游离氨基酸总含量降低13.64%，生酱油呈鲜味的谷氨酸含量由11.52 g/L降至1.26 g/L。表明酸性蛋白酶虽然能够提高原料利用率，但对酱油滋味也有一定影响。

Effects of acidic protease on high-salt dilute-state soy sauce fermentation

Using high-salt dilute-state fermented soy sauce as the research object, the sample without acidic protease as the control group (K), the sample with acidic protease addition (1‰) at the initial stage of soy sauce fermentation (0 d) as the experimental group (S), the changes of acidic and neutral protease activity, pH, total acid, amino nitrogen and free amino acid contents during the fermentation (1-62 d) and the flavor amino acid contents of raw soy sauce were analyzed, the effects of exogenous acid protease addition on soy sauce fermentation was investigated. The results showed that the activities of acidic and neutral protease in group S were 2.9 and 2.1 times of those in group K, respectively. At the end of fermentation, compared with group K, the pH of soy sauce in group S decreased to 4.50, the contents of total acid and amino nitrogen increased 36.71% and 16.49%, respectively, the contents of free amino acid decreased 13.64%, and the content of glutamic acid with an umami flavor decreased from 11.52 g/L to 1.26 g/L. The results showed that although acidic protease could improve the utilization rate of raw materials, it also had a certain impact on the taste of soy sauce.