Study On Mixed Fermentation And Flavor Components Of Whole Navel Orange Wine

This study research on the navel orange wine which brewing with whole fruit of navel orange.First,the optimum fermentation conditions of whole navel orange wine were determined by response surface design.In order to improve the flavor of fruit wine on the premise of keeping high fermentation efficiency,the further optimization of fermentation process of whole navel orange wine by mixed sequence fermentation of Saccharomyces cerevisiae and K.lockera apiculata was carried out under this condition.In addition,we compared and analyzed the flavor substances in four kinds of navel orange fruit wine brewed by different fermentation methods(fermented by whole fruit juice with pomace,whole fruit juice,pulp juice with pomace,pulp juice)and four kinds of whole navel orange wine with different inoculation methods(mixed simultaneous or sequential fermentation of K.lockera apiculata and Saccharomyces cerevisiae,fermented by the two yeast alone).Finally,the antioxidant activity of navel orange wine was determined.Thus,it can provide a theoretical basis for the whole navel orange wine with higher quality,stronger flavor and more typical flavor.The results are as follows:(1)The effects of yeast inoculation amount,fermentation temperature and fermentation time on the fermentation of whole navel orange wine were analyzed by single experiment and Box-Behnken design.The results showed that the influence of various factors on the alcohol accuracy of whole navel orange wine was as follows:yeast inoculum quantity>fermentation temperature>fermentation time.The optimum technological conditions of navel orange whole fruit wine were as follows:yeast inoculation was 6.4%,fermentation temperature was 28?,fermentation time was 14days.Under this condition,the alcohol accuracy and sensory score of whole navel orange wine were 11.23%and 83.7 respectively.(2)Based on the fermentation of whole navel orange wine,the mixed sequence fermentation of Saccharomyces cerevisiae and K.lockera apiculata was adopted.The effects of the addition of K.lockera apiculata,the interval time of Saccharomyces cerevisiae inoculation and the initial sugar content of fermentation broth on the whole navel orange wine were analyzed by single experiment and Box-Behnken design.The results showed that the effects of various factors on the total ester content of whole navel orange wine were as follows:the amount of K.lockera apiculata>the interval inoculation time of Saccharomyces cerevisiae>the initial sugar content of fermentation broth.The optimum technological conditions for mixed sequential fermentation of whole navel orange wine were as follows:the addition of K.lockera apiculata was 6 log cfu/mL,the interval time of Saccharomyces cerevisiae inoculation was 74 h,and the initial sugar content of fermentation broth was 22.7%.Under these conditions,the total ester content was 1.469 g/L,and the alcohol precision was 10.9%.(3)Headspace solid-phase microextraction(SPME)and gas-mass spectrometry(GC-MS)were used to analyze the flavor substances of different navel orange wine.A total of 30?21?21?16 volatile compounds were identified in the four navel orange wine(whole fruit juice wine with pomace,whole fruit juice wine,pulp juice wine with pomacepulp,juice wine),respectively.According to analysis,volatile compounds of the whole fruit wine were predominantly terpenes,while the pulp wine were alcohols(more than 50%).The content of volatile components in whole fruit juice wine with pomace was the most abundant(12.856 mg/L),and the sensory score was the highest.A total of 38 volatile components were detected in whole navel orange wine with four different inoculation methods,including 9 alcohols,11 esters,9terpenes,5 ketones and 5 phenols,among which terpenes accounted for the largest proportion(more than 30%).The volatile components were the highest(37 species,21.957 mg/L)in the mixed sequential fermentation wine,and the mixed simultaneous fermentation wine followed(35 species,20.704 mg/L).What's more,the esters and terpenes in the mixed fermentation wine were significantly higher than those in the single fermentation.(4)The antioxidant activity of four kinds of navel orange wine(whole fruit juice wine with pomace,whole fruit juice wine,pulp juice wine with pomacepulp,juice wine)and navel orange wine sold in the market were determined.The antioxidant capacity of different navel orange wine were compared with the total antioxidant capacity and the scavenging effect of three kinds of free radicals of DPPH·?ABTS~+?·OH.The results showed that the antioxidant capacity of five kinds of navel orange wine was as follows:whole fruit juice wine with pomace>whole fruit juice wine>pulp juice wine with pomace>the market wine>pulp juice wine.