Effects Of Mixed Fermentation,Lees Aging On The Quality Of Cabernet Sauvignon Dry Red Wine

The problems of high sugar and low acidity and homogenization of wine in Xinjiang production areas had existed for a long time.In recent years,the lees aging process that could improve wine quality has been applied to dry red wine,combined it with the use of non-Saccharomyces cerevisiae with specific functions.It was of practical significance to explore the changes in wine quality and taste.Therefore,in this paper,Cabernet Sauvignon grapes were used as raw materials,commercial acid-enhancing non-Saccharomyces cerevisiae CT10 and aroma-enhancing non-Saccharomyces cerevisiae PL09 were used to ferment with three commercial Saccharomyces cerevisiae(MST,CEC01,F33)in a 1:1 order to obtain Cabernet Sauvignon.Raisin red wine(CM,CC,CF,PM,PC,PF).After malate-lactic acid fermentation,the wine samples with better quality were selected for lees aging treatment,and an enzyme solution rich inβ-glucanase was added to accelerate the lees autolysis.By monitoring the fermentation period,aging period and bottle storage process changes in various indicators in the wine,and analyzed the quality and differences of wine.The effects of different yeasts and their purees on the quality of Cabernet Sauvignon dry red wine during lees aging were clarified to provide reference for selecting suitable non-Saccharomyces cerevisiae and purees.The main research results were as follows:1.The fermentation process,physical and chemical indicators,color parameters,phenolic substances and sensory evaluation of wine were analyzed by mixed sequential fermentation.The results showed that:Compared with the fermentation of Saccharomyces cerevisiae,the sequential inoculation of mixed delayed the fermentation period by 2-3 d,increased the content of total acid and dry extract,and improved the total pigment and aggregated pigment of wine samples,made the color more stable;The mixed fermentation samples CM and PF had a significant effect on the tannin,total phenol and total flavonoid content;the sensory scores showed that CM and PF have complex aromas and rounded flavours,with an overall sensory score of “excellent”.2.Analysis of the dynamics of the wine indicators during the un-aged(sample no.-1),aged(sample no.-2),aged in combined with β-glucanase(sample no.-3)and bottle storage processes,The results showed that: Mixed bacteria lees aging and combined enzyme treatment could better protect wine-like phenolic substances,and at the same time had better release and retention ability of polysaccharides,MST-2 had the best effect on protein hydrolysis,MST-3 and PF-3 released Stronger capacity of α-amino acids;After lees aging and enzyme treatment,most of the derived anthocyanins in the wine samples becamed characteristic substances,and the content of pyranoid anthocyanins increased significantly.And in the process of bottle storage,the color tone decreases,and the polymerized pigment increased to stabilize the color of the wine.3.The results of the determination of seven organic acids in wine by high performance liquid chromatography.Mixed fermentation could increased the content of tartaric acid,pyruvic acid,lactic acid,acetic acid and citric acid in wine,while reduced the content of succinic acid;The content of tartaric acid,lactic acid,acetic acid,citric acid and succinic acid increased after aging on Saccharomyces cerevisiae lees;After the mixed fermentation lees aging,tartaric acid,lactic acid,and succinic acid increased,while pyruvic acid,acetic acid,and citric acid decreased,Mixed fermentation,wine lees aging and combined withβ-glucanase treatment all increased the organic acid content of wine to varying degrees,improved the proportion of organic acid components in wine,and achieved the effect of increasing acidity and modifying taste.4.The volatile aroma compounds in wine samples were detected by headspace-solid phase microextraction combined with gas chromatography-mass spectrometry.The results showed that: The total amount of volatile aroma substances in the three groups of CM was better than MST-1,while the content of aroma substances in MST-2 and MST-3 was higher than CM-1.Compared with the control group,the three groups of PF treatments had no positive effect on the total amount of aroma substances but increased the types.The total amount of volatile substances in PF-3 increased by 13.36% compared with PF-2.The main role for these phenomena was the increase and appearance of some esters,alcohols and aldehydes and ketones.Principal component analysed found that the types of aroma substances that contributed the most to single yeast and mixed fermented wine samples were single,but the types increased significantly after lees aging.Sensory evaluation showed that the wine samples of CM-3 had more intense aroma and soft and round taste.