Correlation Between Lactic Acid Bacteria And Flavoring Substances In Wine Malolactic Fermentation Process

Xinjiang Tianshan Beijiao wine production area is located at 44° north latitude,with an average annual sunshine hours of 2,800.The land is large and the climate is pleasant,which has spawned a number of excellent grape growing bases.Wine has a lot of effects and is loved by people,but there is room for improvement in China's winemaking.The fermentation stage of malolactic fermentation after wine alcohol fermentation is an important stage of winemaking.It can change the composition of wine aroma and improve the stability and quality of the product.It is especially important for the production of high-quality red wine.Therefore,this paper explores the dynamic changes of microorganisms in the malolactic fermentation,and understands the unique Malolactic bacteria dominant flora in the northern foothills of Tianshan,Xinjiang,and its aroma effect,which improves the control of red wine fermentation in China and improves the final fermentation.The quality of the products and the characteristics of the terroirs in the Xinjiang producing areas are of great significance.This study used the Cabernet Sauvignon red wine after the alcoholic fermentation of the baron wine barn of Zhangyu Babao in Shihezi,Xinjiang,on the 3rd,6th,9th,and 12 th day after the natural start of malolactic fermentation.Samples were taken on the 15 th day.Analysis of lactic acid bacteria diversity in wine malolactic fermentation using high-throughput sequencing based on Ion S5 TM XL sequencing platform,using headspace solid phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS) The dynamic changes of volatile substances were studied to construct the structureactivity relationship between aroma components and lactic acid bacteria diversity in wine MLF.The main research contents and results are as follows:(1)There are a variety of microorganisms in the wine fermentation process,which together make the wine have a complex flora environment.Yeast is the main process in the alcohol fermentation process,and the lactic acid bacteria are the main in the malolactic fermentation process.After the alcohol fermentation,the Cabernet Sauvignon red wine was used for malolactic fermentation.High-throughput sequencing of wine bacteria during the malolactic fermentation was carried out.A total of 594 progenitor microorganisms of different genera were detected,belonging to Oxyphotobacteria,Proteobacteria,Firmicutes,Bacteroidetes,Actinobacteria,etc.33.A total of 6 families of lactic acid bacteria were detected,including Leuconostocaceae,Lactobacillus,Aerococcaceae,Carnobacteriaceae,Enterococcaceae,Streptococcaceae.17 Lactobacillus,Oenococcus spp. (11-83%),Lactobacillus spp. (10-44%) and Streptococcus spp. (20%) are the dominant lactic acid bacteria.The results of ? diversity analysis showed that the bacterial flora in wine was the highest on the 3rd day of fermentation,and the bacterial flora on the 9th day of fermentation was diverse.The highest diversity.The results of ? diversity analysis showed that there was a big difference between the initial fermentation period and the 6th day of fermentation and the 15 th day of fermentation.The PCoA results showed that the structure of the bacterial flora on the third day of fermentation was the most complicated.(2)There are many chemicals in the wine,and the interaction makes the wine have a good taste,flavor and nutrition.HS-SPME combined with GC-MS was used to study the volatile substances in malolactic fermentation process,and 55 volatile substances were detected,including esters (22),alcohols (10),acids (8),aldehydes.Class(7),ketones (4),terpenes (3),phenols (1).At the beginning of the malolactic fermentation,48 volatile compounds were detected,among which the volatile substances with a relative content of more than 5% were ethyl acetate (5.74%),ethyl octanoate (5.98%),and phenylethyl alcohol (6.72%).The highest relative amount of isoamyl alcohol (32.78%).At the end of the malolactic fermentation (15d),43 volatile compounds were detected,among which the volatile substances with a relative content of more than 5% were ethyl acetate (6.8%),ethyl hexanoate (5.42%),and octanoic acid B.Ester (8.48%),phenylethyl alcohol (6.03%) and the highest relative isoamyl alcohol(20.48%).(3)Combining high-throughput sequencing results with aroma results,the correlation analysis between microbes and volatile components in malolactic fermentation of Cabernet Sauvignon red wine was carried out.Multivariate statistical analysis of O2 PLS model combined with linear regression analysis,Spearman correlation analysis,and typical association analysis (CCA) method were used to establish the dynamic changes of bacterial community and the correlation of flavor substances in wine MLF.The results showed that acids,alcohols,aldehydes,terpenes and phenols were strongly correlated with lactic acid bacteria community diversity.Alcohols were significantly negatively correlated with Oenococcus spp.,and phenols were significantly positively correlated with Streptococcus spp..There was a significant positive correlation between Oenococcus spp.and octanoic acid,and a significant negative correlation with phenylethyl alcohol and terpinol.Lactobacillus spp.is significantly negatively correlated with linalool and benzyl alcohol.Streptococcus spp.is significantly negatively correlated with linalool and ethyl hexanoate.