川南麸醋入池发酵过程中理化指标变化规律研究

连续测定川南某醋厂入池发酵过程中7项理化指标的动态变化。试验结果表明,水分变化不大,从整个周期来看,略有提升;淀粉在整个入池发酵过程中从33.81g/100g干醅降低到26.12g/100g干醅,利用率只有21.71%;还原糖和酒精都是中间代谢产物,发酵过程中不断生成但同时又被消耗利用,都呈先增加后降低的趋势;氨基酸态氮含量一直上升,从0.42g/100g干醅上升到1.14g/100g干醅;不挥发酸和挥发酸为麸醋的主要成分,且一直呈上升趋势,不挥发酸最高含量达到8.99g/100g干醅(以乳酸菌计),挥发酸最高含量达4.71g/100g干醅(以乙酸计)。研究发现,川南麸醋入池发酵过程可分成3个阶段,其中0~1d主要为糖化、酒化、醋化阶段,2~7d主要为酒化、醋化阶段,还有缓慢的糖化作用,8~13d主要是醋化阶段。由于是生料发酵,川南麸醋入池发酵阶段存在明显的淀粉利用率偏低的现象。

Study on the Change Rules of Physicochemical Indexes During the Pit-entry Fermentation Process of Southern Sichuan Bran Vinegar

The dynamic changes of 7 physicochemical indexes in the pit-entry fermentation process of a vinegar factory in southern Sichuan are determined continuously.The experimental results show that the water content changes little and increases slightly during the whole fermentation process.Starch is reduced from 33.81 g/100 g dry grains to 26.12 g/100 g dry grains in the whole fermentation process,with the utilization rate of 21.71% only.Both reducing sugar and alcohol are the intermediate metabolites which are constantly produced in the fermentation process but consumed at the same time,they are increased firstly and then decreased.The content of amino acid nitrogen increases from0.42 g/100 g dry grains to 1.14 g/100 g dry grains.Non-volatile acid and volatile acid are the main components of bran vinegar,and their content is increased during fermentation process.The highest content of non-volatile acid can reach to 8.99 g/100 g dry grains(measured by lactic acid),and the highest content of volatile acid can reach to 4.71 g/100 g dry grains(measured by acetic acid).According to the research,the fermentation process of southern Sichuan bran vinegar can be divided into three stages,among which,0~1 day is mainly saccharification,alcoholization and acetification stage;2~7 days is mainly alcoholization and acetification stage with slow saccharification,8~13 days is mainly acetification stage.Whereas the starch utilization rate is obviously low in the pit-entry fermentation process of southern Sichuan bran vinegar due to raw material fermentation.