山西老陈醋发酵过程中细菌群落组成与有机酸变化的关系研究

Study on the Relationship between Bacterial Community Composition and Changes of Organic Acids during Fermentation Process of Shanxi Aged Vinegar

山西老陈醋含有丰富的有机酸,发酵过程微生物种类众多,共同作用赋予山西老陈醋独特的口感,其中细菌是主要的产酸微生物。研究对山西老陈醋整个发酵过程细菌群落组成和有机酸变化规律进行了分析,并利用典范对应分析(CCA)方法对它们之间的关系进行了研究。PCR-DGGE对发酵过程中细菌群落组成分析总共检测到优势菌18株,包括乳酸菌12株,醋酸菌2株,未培养细菌4株,发酵过程中细菌多样性在酒精发酵阶段和醋酸发酵初期逐渐增加,在醋酸发酵后期开始减少,其中部分乳酸菌醋酸发酵阶段开始减少直至消失,醋酸菌在醋酸发酵阶段开始出现并且逐渐增加。乙酸和乳酸占有机酸总量的90%以上,是山西老陈醋的主体有机酸。CCA对应分析结果表明发酵过程中对乙酸生成贡献率较大的菌株分别为Acetobacter pasteurianus>Gluconacetobacter liquefaciens>Lactobacillus panis>Lactobacillus helveticus,对乳酸生成贡献率较大的菌株分别为Lactobacillus reuteri>Lactobacillus malefermentans>Lactobacillus fermentum。

Shanxi aged vinegar contains various organic acids that give the vinegar unique flavor.The organic acids are mainly produced by kinds of bacterial during the fermentation process.This research studies the succession of bacterial community and the changes of organic acids during fermentation process.The relationship between them is analyzed with the method of canonical correspondence analysis（CCA）.PCR-DGGE method is used to analyze the bacterial community during fermentation process. 1 8 strains of bacteria, containing 1 2 lactic acid bacteria, 2 acetic acid bacteria and 4 uncultured bacteria are detected.The bacterial diversity increases at the stage of alcohol fermentation, and then decreases at the end of acetic acid fermentation .Several lactic acid bacteria disappear duringacetic fermentation process.Acetic acid bacteria appear and increase gradually during acetic acid fermentation.Acetic acids and lactic acids are the main organic acids,which offer over 90% of total organic acids of Shanxi aged vinegar.Canonical correspondence analysis （CCA）shows that bacteria which contribute to acetic acid formation are Acetobacter pasteurianus 〉 Gluconacetobacter liquefaciens 〉Lactobacilluspanis 〉Lactobacillushelveticus,and bacteria which contribute to lactic acid formation are Lactobacillusreuteri 〉Lactobacillusmalefermentans 〉Lactobacillus fermentum respectively.