Research On Strawberry Fruit Wine Strain Screening And Sequential Mixed Bacteria Fermentation Technology

The brewing of strawberry fruit wine is one of the effective ways to enhance the added value of strawberries.In order to explore its market potential and meet the preferences of different consumers,it is crucial to improve the flavor quality of strawberry fruit wine.The screening of fermentation strains and the study of mixed strain fermentation methods are one of the main breakthrough points for flavor optimization.In this study,the strawberry wine fermented from the strawberry base of Wenji Town,Yingquan District,Fuyang City,Anhui Province,was selected from wild yeast isolated from the soil of strawberry garden,ripe strawberry peel and natural fermentation mash of strawberry,and the fermentation performance was analyzed with the yeast strain from the strain preservation center of China Academy of Food and Fermentation Industry.The yeast strains with excellent fermentation characteristics were then combined with non-brew yeast to evaluate the basic physicochemical indexes,sensory and volatile organic compounds of the finished wine,with the aim of screening out the sequential mix of fermentation strains that can improve the quality and aroma richness of strawberry fruit wine,and providing theories for the development of high-quality strawberry fruit wine.theoretical guidance for the development of high-quality strawberry fruit wine.The results of the study are as follows.1.A total of 20 strains were isolated and purified from the root soil,strawberry epidermis and natural fermentation mash of strawberries produced at the strawberry base in Wenji Town,Yingquan District,Fuyang City,Anhui Province,combined with 7 strains of yeast originally conserved in the laboratory,two yeast strains with better performance were obtained through multi-layer screening,one of which is a known yeast 32929 abnormal Wickerhamomyces anomalus,and another strain of yeast B12,whose colony morphology is white,elevated in the middle,opaque,sticky and creamy,with neat edges,can tolerate higher concentrations of ethanol,sucrose,citric acid and sulfur dioxide,with strong growth ability and excellent overall fermentation performance,after molecular biology identification and genetic evolution After molecular biology identification and genetic evolution analysis,B12 yeast was identified as Pichia kluyveri.2.Seven commercially available commercial yeasts were used to ferment strawberry wine,and the basic physicochemical properties and the contents of three bioactive components of total phenols,anthocyanins and flavonoids were compared at the end of fermentation,and the types and contents of volatile organic compounds in the strawberry wine obtained by fermentation were analyzed by GC-IMS technique.The results showed that the fermentation quality of L2323 commercial yeast was good and the content of bioactive components in the strawberry wine produced by it was relatively high;and the content of esters in the strawberry wine produced by it was the highest,including 1-penten-3-one,ethyl caprylate,ethyl isobutyrate,ethyl butyrate,ethyl propionate,ethyl caprylate,isopentyl acetate,isobutyl acetate and ethyl 2-methylbutyrate.The comprehensive analysis concluded that the overall quality of strawberry wine brewed by L2323 yeast was excellent and the aroma substance content was richer,therefore,L2323 yeast was selected as the brewer’s yeast strain for the subsequent sequential mixed bacteria fermentation study.3.Two strains of non-brewery yeast B12 and 32929 were fermented with L2323 commercial brewer’s yeast in sequential mixed bacteria,and the sequential inoculation treatment groups were set as LB12,LB12 24 h,LB12 36 h,LB12 48 h,LY3,LY3 24 h,LY336 h,LY3 48 h,and a comprehensive comparison of the physicochemical indexes and bioactive substances of the B12 yeast fermentation group and the 32929 yeast fermentation group was found.It was found that in the sequential mixed fermentation of B12 yeast,32929 yeast and L2323 commercial yeast,the commercial yeast could improve the characteristics of poor alcohol production,slow sugar consumption and high acidity of strawberry wine fermented by non-brewery yeast;the mutual synergistic effect of mixed fermentation could improve the consumption of anthocyanin content by commercial yeast fermentation to a certain extent.The volatile flavor substances of strawberry fruit wine in different inoculation sequence treatment groups were detected by GC-IMS technique,and 32 aroma compounds were detected,mainly esters and alcohols,among which the flavor typicality of strawberry wine in B12 pure seed fermentation group was the most unique.Combined with the sensory evaluation,LB12 36 h,i.e.B12 Pichia kluyveri and L2323 The commercial yeast,36 h sequential inoculation is the suitable fermentation combination for making strawberry fruit wine,and this combination can give full play to the aromatic effect of B12 non-enological yeast,and the sensory evaluation is the best.