Kinetics Of The Main By-products And Esters In Mixed Fermentation With Non-saccharomyces Cerevisiae And Saccharomyces Cerevisiae

In recent years,researchers began to re-evaluate the role of non-Saccharomyces cerevisiae in mixed fermentation with Saccharomyces cerevisiae.Studies have shown that Some non-S.cerevisiae with high esterase activity can regulate the content of esters in wine during fermentation and increase the fruity characteristics.In addition,more and more researchers have begun to pay attention to the influence of the main by-products like glycerin,polysaccharide,succinic acid,lactic acid and volatile acid in mixed fermentation between the non-S.cerevisiae and S.cerevisiae to evaluate the quality as an important basis.Therefore,in order to evaluate the effect of non-S.cerevisiae and S.cerevisiae in mixed fermentation on wine flavor quality,this paper intends to study the kinetics of the esters and the main by-products in mixed fermentation between non-S.cerevisiae and S.cerevisiae.Which can provide the theoretical and practical support on the application of mixed fermentation with non-S.cerevisiae..In this study,there are three Non-S.cerevisiae strains were selected from the winemaking environment,Establishing the fermentation kinetics equation to explore the relationship between esters,main byproducts,cell growth and sugar consumption in mixed fermentation,which can provides the basis for better optimization and control the fermentation process.The main results are as follows:(1)The growth of yeasts in mixed fermentation with Non-S.cerevisiae and S.cerevisiae:Compared with the S.cerevisiae,the total number of yeasts in mixed fermentation was higher.In sequential inoculation fermentation,the cells survival time of Pichia fermentans was the longest while the Rhodotorula mucilaginosa was the shortest,that indicating the S.cerevisiae has some inhibitory effects on the Non-S.cerevisiae.(2)The change of Sugar consumption and alcohol in mixed fermentation with Non-S.cerevisiae and S.cerevisiae.Compared with the S.cerevisiae,in sequential inoculation fermentation,the delayed inoculation of S.cerevisiae that reduce the rate of sugar consumption,the kinetics curve is different from S.cerevisiae.At the same time,In sequential inoculation between Hanseniaspora uvarum and S.cerevisiae,the sugar consumption was completely while R.mucilaginosa was the lowest.(3)The change of the main by-products in mixed fermentation with Non-S.cerevisiae and S.cerevisiae.The generated by-products in mixed fermentation with non-S.cerevisiae and S.cerevisiae were synchronized with the growth of yeasts.Compared with the S.cerevisiae,in sequential fermentation,the P.fermentans,R.mucilaginosa can significantly increase the content of glycerol,polysaccharides,lactic acid,reduce the volatile acid,at the same time,the glycerol and succinic acid were increased in simultaneous mixed fermentation between the H.uvarum and S.cerevisiae.(4)The change of the esters in mixed fermentation with Non-S.cerevisiae and S.cerevisiae.The total amount of aroma generated in mixed fermentation was higher than S.cerevisiae.In simultaneous inoculation mixed fermentation with of P.fermentans and S.cerevisiae,that has significantly increased the ethyl acetate,isobutyl acetate,phenylethyl acetate.Ethyl butyrate,ethyl hexanoate,ethyl octanoate,ethyl lactate,Isoamyl octanoate.The total content of esters is increased and the aroma intensity of the wine is increased.The sequential inoculation treatment can significantly increase the content of other esters and the complexity of the wine flavor.