金种子浓香型大曲中产蛋白酶嗜热细菌的筛选及其产香分析

Screening of Thermophilic Protease-producing Bacteria Strains from Jinzhongzi Nongxiang Daqu and Analysis of Its Flavoring Components

产蛋白酶嗜热细菌在芝麻香功能复合曲中具有重要应用价值。根据其产芽孢与蛋白酶的特性,利用热处理、酶活检测、高温培养等方法,从金种子浓香型大曲中分离出6株产蛋白酶嗜热细菌。其中,菌株Nxzd4的强化麸曲蛋白酶活力较高。利用液态培养进行单菌种发酵,并应用GC-MS检测其馏分的香气成分。结果表明,6株菌株液态发酵产香成分均不相同,但均可检测到芳香族化合物、酚类、酯类等风味物质;其中,菌株Nxzd1产香较为丰富,菌株Nxzd2、Nxzd4还产生乙偶姻、吡嗪等芝麻香酒特征性风味物质。该研究为制备金种子功能复合曲提供了研究基础。

Thermophilic protease-producing bacteria is of important application values in Zhimaxiang functional compound starter. Based on its properties of producing spores and protease, 6 thermophilic protease-producing bacteria strains were isolated from Jinzhongzi Nongxiang Daqu through heat treatment, protease activity detection, and high- temperature cultivation. Among them, the strengthened bran starter of strain Nxzd4 had higher protease activity. Meanwhile, the flavoring components acquired from liquid fermentation of each individual bacteria strain were analyzed by GC-MS. The results showed that, the flavoring components produced by the 6 bacteria strains were not the same, however,some flavoring substances including aromatic compounds, phenols, and esters etc. could be detected for all 6 bacteria strains. Among them,strain Nxzd1 could produce abundant flavoring components, while strain Nxzd2 and Nxzd4 could produce acetoin and pyrazine etc., which were characteristic flavoring substances of Zhimaxiang Baijiu（liquor）. This study provided research base for the preparation of Jinzhongzi functional compound starter.