Selection And Identification Of Saccharomyces Cerevisiae In Shanxi Grape Production Area And Analysis Of Its Co-fermentation Characteristics

Shanxi Province is located in the western part of the North China Plain and the eastern part of the Loess Plateau.It is one of the top ten grape-growing regions in China.The wine production has a long history.It has the characteristics of dry early climate and long frost-free period.Its native wild yeast resources are diversified.Exploit the resource potential of unique strains of brewer's yeast for making high-quality wine.In this study,112 yeast strains were isolated from grape berries and vineyard soil-related samples from seven cities in Shanxi Province.After three-level screening of 112 isolated and purified strains including determination of fermentability,tolerance performance and basic characteristics,three yeast strains with excellent comprehensive performance were obtained,numbered GP1,FT9,and FM3.All three preferred yeast strains are available.It starts fermentation within 12 hours and can tolerate 15%alcohol,60%glucose concentration,350 mg/L SO₂;GP1,FT9 can tolerate 1.6 acidity,FM3 can tolerate 2.1 acidity;GP1 can tolerate Subject to a high temperature of 42?,FT9 and FM3 can tolerate a high temperature of 39?;the three preferred yeast strains are all strains with high alcohol and low hydrogen sulfide production;GP1 and FM3 are high-ester and low-foam-yielding yeasts,and FT9 is middle-ester and middle-yield Foamy yeast.The 3 strains of native yeasts were tested for the fermentation of Cabernet Sauvignon wine,and the physical and chemical indexes of the fermentation process were determined.After the fermentation is terminated,the reducing sugars in the fermentation broth of the wines brewed by the 5 yeast strains are between 3.08 and3.62 g/L,the alcohol content is between 12.5%and 14.2%,and the total acid is between 6.33 and 7.09 g/L.The requirements for wine in the national standard.The various indicators of GP1 brewing wine are the most prominent,which are better than the two control bacteria.Its alcohol content,reducing sugar content and total acid value are 14.2%vol,3.08 g/L,and 6.33 g/L,respectively.According to the sensory evaluation results,the wine made by the GP1 strain had the highest score,which was better than the two control commercial yeasts.It is suitable for wine making and can be used for co-fermentation wine production strains.The preferred native yeast GP1 was identified by WL and classified as Saccharomyces cerevisiae.The tolerance performance of the non-Saccharomyces cerevisiae Isa orientalis(DF)purchased from CICC is tested,which can adapt to the wine-making environment.The preferred native strain GP1 and non-Saccharomyces cerevisiae DF were mixed and co-fermented at 3%inoculum ratios of 1:9,3:7,and 5:5 in a mixed co-fermentation experiment.After the fermentation was terminated,the fermentation of each treatment was determined.Liquid indicators.The content of anthocyanins,tannins,total phenols,alcohol,reducing sugars and total acids is 124.85?146.68 mg/L,372.45?418.07 mg/L,2079?2214 mg/L,13.5?14 degrees,3.48?3.69 g/L,between6.24 and 6.41 g/L,all meet the requirements for wine production in the national standard.The aroma components of each wine sample were determined and analyzed.A total of 59 aroma components were detected in the wine samples fermented by GP1single bacteria,and 56-62 aroma components were detected in the wine samples with the inoculation ratio of mixed bacteria co-fermentation.The total content of esters and alcohols in co-fermented wine samples is higher than that of the preferred native Saccharomyces cerevisiae GP1 monobacterium fermented wine samples,and the increase in wine samples with an inoculation ratio of 3:7 is more prominent.The total content of organic acids and other compounds such as phenols and ketones in co-fermented wines is not much different.Sensory evaluation of each wine sample,the highest score is the inoculation ratio of 3:7 mixed fermentation wine,83.6 points,therefore,the best inoculation ratio is 3:7.