Study On The Optimization Of Chishui Sun-tanning Vinegar Fermentation Process

Chishui sun-tanning vinegar adopts traditional folk hand-brewing techniques,selects high-quality rice,glutinous rice and bran as the main raw materials,and uses vinegar koji made from more than 100 kinds of Chinese herbal medicine as saccharification starter.It is brewed by more than 30 processes such as exposure,and the brewed vinegar has the characteristics of color,aroma,acid,alcohol,and concentration,and it is deeply loved by consumers.However,this traditional hand-brewed vinegar has the problems of low utilization rate of starch in raw materials and low acid production.In order to change the status quo of process defects,this study first selected acetic acid bacteria with high acid production and strong tolerance from the chishui sun-tanning vinegar,which was used to strengthen the acetic acid fermentation.Finally,the results of process improvement are applied to actual production,so that the vinegar drying process can be optimized.The research results are as follows:Screening of acetic acid bacteria in vinegar and vinegar: In order to avoid the adverse effect of the addition of acetic acid bacteria on the vinegar fermentation system,the traditional acetic acid bacteria screening method was used to obtain acetic acid bacteria C1,C5 and C6 from the vinegar and vinegar.Both belong to Acetobacter pasteurianus.In terms of acid production capacity,acetic acid bacteria C1 and C6 are far stronger than C5.In terms of tolerance,the acetic acid bacteria C1 and C6 are significantly more resistant to ethanol and acid than C5,and their salt resistance is equivalent.Therefore,acetic acid bacteria C1 and C6 can be used to enhance the acetic acid fermentation stage of sun vinegar production;Simulated experiment of improved vinegar fermentation process: In the laboratory,simulation of red water vinegar fermentation process was improved,and other fermentation conditions remained unchanged,the original fermentation processwas adjusted by adjusting the ratio of raw materials and water in the vinegar fermentation process The material-water ratio was adjusted from 1:14 to 1: 7 and the result was the best.Examination of vinegar koji enzyme activity found that the low activity of vinegar koji liquefaction enzyme resulted in insufficient starch liquefaction,which affected the production of sugar and alcohol.It was found through experiments that when the amount of liquefaction enzyme reached 90 u / g starch,the raw material liquefaction process was suitable.In the case of a change in the feed-water ratio,the liquefaction process was improved by adding amylase and vinegar,respectively.The results showed that adding enzymes to strengthen the process was better than increasing the amount of vinegar;Application of the improved process in the production of vinegar: The improved vinegar process is applied to actual production.The results show that the effect of the alcohol fermentation stage is obvious,and the alcohol content of the mash is increased from 1.285% Vo L to 5.24% Vo L in the original fermentation process.However,the substantial increase in the alcohol content of the mash has led to the inhibition of the growth of acetic acid bacteria in the later acetic acid fermentation and the occurrence of fermentation abnormalities.The acetic acid bacteria C1 and C6 obtained by screening are expanded into the vinegar and the acetic acid fermentation process is strengthened The acidity of the final vinegar increased from 3.17 g / 100 ml to 6.21 g /100 ml in the original fermentation process,and the utilization rate of starch in the vinegar from 18.30% reached 34.87%.By testing the volatile components of the improved fermentation process at the end of alcohol fermentation and the end of acetic acid fermentation,compared with the original fermentation process,it was found that there is no major difference in the types of volatile components,mainly because the relative content of volatile components has increased or decreased.In particular,the relative content of alcohol and acid in the improved process has increased significantly,and at the same time,some other volatile components are lower than the original fermentation process,but this change is small,and the relative content is less than 1%.Generally speaking,compared with the original fermentationprocess,the improved fermentation process significantly improves the utilization of raw materials and acid production,and does not cause any major changes to the flavor substances in the fermentation stage.