Microbial Communities Of Rice Wine Starters And The Improvement Of Baerqu

Chongming rice wine has a long history and rich nutrition,there are some defects in Chongming rice wine such as pungency and afterbitterness,and it is still in the stage of manual brewing.In order to improve the quality of Chongming rice wine and provide reference for the standardization and modernization,the high-throughput sequencing technology was used for the first time to systematically explore the microbial communities in Chongming Baerqu,starters from Ningbo and Yichang.The fungi and bacteria in three starters were isolated,identified and screened.The high-quality strains were used to prepare optimized Baerqu.Modern detection methods were used to explore the quality of rice wines.It was found that the optimized Baerqu had great fermentation effect and the flavor of rice wine could be improved.The main results are as follows:?1?Through high-throughput sequencing technology analysis,it was found that the dominant genera?relative abundance more than 1.0%?of CMQ were Pantoea?96.3%?,Bacillus?1.6%?,Rhizopus?93.1%?and Candida?2.0%?.The dominant genera of NBQ were Lactobacillus?33.8%?,Acetobacter?27.3%?,Pediococcus?22.3%?,Weissella?12.4%?,Bacillus?2.1%?,Candida?86.9%?,Aspergillus?11.5%?and Rhizopus?1.2%?.The dominant genera of YCQ were Pediococcus?22.6%?,Leuconostoc?22.2%?,Weissella?6.1%?,Fraxinus_excelsior?4.2%?,Lactococcus?3.7%?,Ochrobactrum?2.9%?,Lactobacillus?2.7%?,Rhizopus?63.1%?and Mucor?1.2%?.?2?Eight bacteria,eight molds and twelve yeasts were isolated from CMQ,NBQ and YCQ.After screening,we got the Rhizopus oryzae ZJM3 and Mucor circnelloides ZJM5 with strong saccharification ability.The results showed that NBY003,CMY001 and YCY001 with strong fermentation ability,CMY002,CMY003 and NBY002 with strong aroma and ester production ability.67 kinds of volatile aroma compounds were detected in the fermentation broth of three strains.There were 47,43 and 37 volatile aroma compounds in NBY002,CMY002 and CMY003 fermentation broth respectively.The high quality yeast strains Saccharomyces cerevisiae CMY001,Wickerhamomyces anomalus CMY002 and Candida glabra YCY001 were screened out by the comprehensive fermentation capacity,aroma,ester and tolerance.?3?The quality evaluation model of rice wine was obtained by PCA analysis:Y=1.177X₁+1.283X₂-0.903X₃-1.660X₄+0.653X₅+91.556Where X₁ is alcohol content;X₂ is non-sugar solidity content;X₃ is total sugar content;X₄ is total acid content and X₅ is amino acid nitrogen content.The R2 of the model was 0.902,indicating that the goodness-of-fit was good,and the P value was 0.001,indicating passing the test of significance level.The relative error of the model was less than 1%,which can evaluate the sensory quality of rice wine accurately and objectively.?4?Five strains of high quality were selected to make the optimized Baerqu,the physicochemical indexes and enzyme activities of the optimized Baerqu were determined.The quality of rice wine was determined by the quality evaluation model.The quality of optimized Baerqu prepared by ZJM3,CMY001,CMY002 and YCY001 was the best.?5?SPME-GC/MS technology was used to detect the volatile aroma components in rice wine fermented by CMQ,NBQ,YCQ,RQ and market rice wine.The content of ?-phenylethanol was the highest in rice wine made from optimized Baerqu.In addition,palmitic acid,ethyl laurate,ethyl tetradecanoate,ethyl palmitate,ethyl oleate and ethyl linoleic acid were only found in rice wine made from optimized Baerqu.Five kinds of rice wine were detected by Heracles II electronic nose,found that the smell was obvious different.The difference of odor information between rice wine made from optimized Baerqu and NBQ was small,followed by CMQ,and significant with rice wine made from YCQ and market rice wine.Five kinds of rice wine were detected by electronic tongue.It was found that compared with CMQ rice wine,the rice wine brewed by optimized Baerqu had a significant decrease in acidity,astringency,sweetness and bitterness aftertaste were decreased,while the fresh and fresh aftertaste were significantly increased.Compared with the market rice wine,the acidity,sweetness and fresh aftertaste is significantly higher,while the bitterness,fresh,astringency,bitterness aftertaste and astringency aftertaste are significantly lower.In the synthesis the factor,the effect of optimized B aerqu could effectively improve the flavor of rice wine.The above research results can effectively improve the quality of Chongming rice wine and provide reference for promoting the standardization and modernization of its industry.