| With the continuous expansion of the coffee market and the continuous growth of domestic coffee consumption,the coffee cultivation industry in China has also developed rapidly.At present,most coffee producing areas in China are concentrated in Yunnan Province.In order to reduce the waste of resources and increase the income of local farmers,a non-saccharomyces cerevisiae,Pichia kluyveri,with excellent aroma production effect and high wine production rate,was selected by using coffee peel as raw material in this paper.With the saccharomyces cerevisiae in 7 kinds of proportion(1:0,1:0,1:1,10:1,100:1,1000:1,10000:1 v/v)mix fermented fruit wine,coffee and its physical and chemical substance,characteristic,and aroma measured active substances,in combination with sensory evaluation of coffee wine quality were analyzed.The main contents and conclusions are as follows:(1)After LYS culture-medium screening,olfactory method,Duchente tubule fermentation method and basic physicochemical index detection,yeast CB9,which has good aroma production effect and high wine production rate,was screened from coffee peel.Through staining observation,it was found that the colony of strain CB9 was round shape,smooth and flat surface,suitable for large-scale culture and brewing.Pass.A surname.Based on morphological observation and molecular identification of 18 S r DNA,CB9 was identified as Pichia kluyveri and selected as non-saccharomyces cerevisiae for mixed fermentation by comparing with phylogenetic tree.(2)The physical and chemical indexes and characteristic substances of coffee wine were investigated by inoculating saccharomyces cerevisiae with seven different proportions of fermentation.It was found that the addition of high concentration of Pichia kluvei retained higher residual sugar content.The total acid content increased first and then decreased with the addition of Pichia cruviae.Both types of yeast significantly affected the alcohol content,and the group with saccharomyces cerevisiae had higher alcohol content.In addition,through the detection of caffeine,rutin,trigonelline,chlorogenic acid and mangiferin in coffee wine,it can be concluded that mixed bacteria fermentation can produce higher caffeine content.The content of mangiferin was not affected by the ratio of yeast,but the content of mangiferin was the highest when the ratio of saccharomyces cerevisiae to Pichia cruvei was 1:1.Pichia kluvei could stimulate the content of rutin and trigonelline.The content of chlorogenic acid was affected by the proportion of yeast,and the overall concentration showed a trend of first increasing and then decreasing.(3)The volatile compounds of coffee wine were analyzed by gas chromatography-mass spectrometry.A total of 56 aroma compounds were obtained.The content of higher alcohols was increased by 84.64% by mixed fermentation,and the floral flavor was enhanced.The amount of ethyl ester in the wine body is also increased,adding grassy notes and caramel notes.At the same time,the mixed bacteria fermentation also significantly increased the acid substances in the wine samples,the highest increase of 149.76%,making the wine more refreshing.The inoculated fermentation group by OAV analysis not only increased the aroma components of 8esters,but also increased many alcohols,phenols and terpenes that could be perceived by smell.Finally,according to the sensory analysis of the wine samples,combined with physical and chemical experiments and aroma components,it can be concluded that mixed fermentation is conducive to brewing a new type of coffee wine with strong aroma and rich taste.When Pichia pastoris kluviae and saccharsacchara cerevisiae are inoculated at a ratio of 1:1,more floral,sweet and woody aromas can be added to the wine body. |
PDF Full Text Request