酶法制备大豆多肽及在酱油发酵中的应用

以脱脂大豆粕为原料，采用复合酶解技术制取大豆多肽酶解液，将制备的大豆多肽应用于酱油发酵前期，并从酱油理化指标、感官评价及香气分析三方面归纳其对酱油主要品质的影响。结果表明，先加中性蛋白酶（温度55 ℃，pH值为6.5，酶用量为4 500 U/g蛋白，酶解3 h）后，再加入碱性蛋白酶（温度55 ℃，pH值为9.0，酶用量为3 000 U/g蛋白，酶解1 h）。此时水解度达22%，多肽得率达10.84%。添加大豆多肽的酿造酱油色泽棕红亮，醇香、酱香浓郁，整体滋味均优于普通酿造酱油。气质联用（GC-MS）鉴定出酱油中含挥发性风味化合物40种，其中主要香气化合物为醇类69.41%、酸类23.06%、醛酮类4.45%、杂环酯类2.47%等，大豆多肽提高了酿造酱油的综合品质，滋味和香气明显优于传统发酵酱油，可用于开发功能营养型酱油。

Preparation of soybean polypeptide by enzymatic method and its application in soy sauce fermentation

Using defatted soybean meal as raw material, the soybean polypeptide hydrolysate was prepared by composite enzymatic technology. The prepared polypeptide was applied in the early stage of soy sauce fermentation, and the physicochemical indexes, sensory evaluation and aroma analysis of the soy sauce quality was evaluated. The results showed that soybean peptides were prepared with double-enzyme hydrolysis by adding neutral protease firstly (temperature 55 ℃, pH 6.5, enzyme 4 500 U/g protein, enzymolysis time 3 h), and adding alkaline protease afterwards (temperature 55 ℃, pH 9, enzyme 3 000 U/g protein, enzymolysis time 1 h). Under the condition, the hydrolysis degree was 22%, and the polypeptide yield reached 10.84%. The soy sauce added soybean peptide was reddish brown in color bright, mellow, rich in sauce-flavor, and the overall taste and sensory evaluation was superior to common soy sauce. Over 40 volatile flavor compounds in soy sauce was identified by GC-MS, of which the main aroma compounds were alcohol 69.41%, acid 23.06%, aldehydes and ketones 4.45%, heterocyclic esters 2.47%, etc. The whole quality of soy sauce was improved when the soybean polypeptide was involved in the early stage fermentation. The aroma and flavor was significantly superior to the traditional fermented soy sauce, so they can be used to develop nutrition-based, functionality of soy sauce.