Effect Of Co-fermentation By Williopsis Saturnus And Saccharomyces Cerevisiae On The Flavor Of Jujube Wine

Fermented fruit wine is a low-alcohol beverage produced by yeast which convert sugar in fruit to alcohol.It can not only keep most of the nutrients in the fruit,but also contain the beneficialsubstances produced by microbial metabolism,which is benefici al to human health.Jujube has a long history of cultivation in China and is a traditional food with the same origin of medicine and food.Jujube fermented wine made from jujube is rich in nutrition,which not only increases the added valueof jujube,but also enriches the variety of fruit wine on the market.However,at present,the fermented wine of jujube is usually fermented by Saccharomyces cerevisiae,which cannot well reflect the complexity and typicality of jujbe wine’s flavor.In this experiment,in order to obtain high quality jujube wine with typical jujube flavor,the dry jujube was took as the research object,we studied the effects of the types and addition of assimilable nitrogen,the process and parameters of fermented jujube wine by Wine yeast and the process and parameters of mixed fermentation of Williopsis saturnus and Wine yeast on the flavor of jujube wine,finally,the antioxidant activity of fermented jujube wine was determined.The findings are as follows:(1)The optimum technological parameters of fermented jujube wine by Sacc haromyces cerevisiae determined by single factor experiment were:the addition of diammonium hydrogen phosphate was 320 mg/L,the inoculation amount of Saccha romyces cerevisiae was 0.25%,the initial saccharification of fermentation broth was20°Bx,the initial pH of fermentation broth was 4 and the fermentation temperature was 24℃.On this basis,the regressive model of Saccharomyces cerevisiae addition,initial saccharification,fermentation temperature,the addition of diammonium phosph ate and alcoholic strength was established by the response surface analysis,alcoholic=+11.20+0.31*A+0.64*B+0.20*C+0.30*D+0.25*A*B+0.15*A*C-0.18*A*D+0.42*B*C+0.35*B*D+0.075*C*D-1.29*A~2-1.19*B~2-1.63*C~2-1.53*D~2,the addition of Sacch aromyces cerevisiae was 0.26%,the initial saccharification was 21°Bx,the optimal technological condition of fermented jujube wine was determined which the fermen tation temperature was 24℃and the addition of diammonium phosphate was 330 mg/L,under this condition,the alcohol content of the product was 11.20%.(2)On the basis of the process of Saccharomyces cerevisiae fermentation,using the sequential mixing fermentation by Williopsis saturnus and Saccharomyces cerevisiae,the process parameters of the sequential mixing fermentation were determ ined by single factor experiment which the initial concentration of jujube plup was150 mg/L,the addition of Williopsis saturnus was 0.75%and the action time of Williopsis saturnus was 72 h.On this basis,the regressive model of the initial concentr ation of jujube plup,the addition of Williopsis saturnus,the action time of Williopsis saturnus and the content of total ester during the fermentation of jujube wine was established by the response surface analysis,total ester=1.23+0.065*A+0.070*B+0.048*C+0.012*A*B-0.028*A*C-0.038*B*C-0.10*A~2-0.11*B~2-0.13*C~2,the optimum ferm entation conditions of sequential mixing fermentation was determined which the initi al concentration was 166 mg/L,the addition of Williopsis saturnus was 0.83%and the action time of Williopsis saturnus was 74 h,under this condition,the total ester of the product was 1.23 g/L.(3)The aroma components of jujube wine in three different ways(the pure fermentation of Saccharomyces cerevisiae,the pure fermentation of Williopsis saturn us and the sequential mixing fermentation of Williopsis saturnus and Saccharomyces cerevisiae)were compared and analysed by HS-SPME-GC-MS.The results show that the main aroma components of three kinds of jujube wine were accohols and esters and the kinds and concentration in the jujube wine through sequential mixing ferme ntation were higher than pure fermentation(P<0.05).The concentration of ethyl octanoate(floral,fruity,brandy),ethyl caprate(fruity,grape),ethyl laurate(fruity,floral)in the sequential mixing fermentation jujube wine were 0.12 mg/L,0.16 mg/L.1.24mg/L,and the OAV>1,which has the positive contribution to the flavor of jujube wine.(4)The total phenol content of fermented jujube wine and two kinds of jujube wine purchased in the market was determined by Folin-Ciocalteu,the antioxidant capacity of them was studied by the determination of the clear rate of free radical of DPPH·,the clear rate of·OH and the determination of superoxide anion free rad ical.The results show that the total phenol content of the fermented jujube wine,the market of jujube wine A and the market of jujube wine B were 1.104 mg/mL、0.378mg/mL、1.039 mg/m L,respectively.The ablity of clearing the DPPH·was fermented jujube wine>the market of jujube wine B>the market of jujube wine A,the ablity of clearing the·OH was the market of jujube wine B>the market of jujube wine A>fermented jujube wine,the ablity of clearing the superoxide anion was fermented jujube wine>the market of jujube wine B>the market of jujube wine A.