Study On The Effect Of Mixed Fermentation On The Flavor Of Citrus Wine

Citrus fruit wine is a kind of Citrus fermented product with low alcohol content.The development of high-quality citrus wine can increase the added value of Citrus raw materials and has a good development prospect.However,at present,the understanding of citrus varieties is not deep enough,and there is no special variety suitable for wine making,which leads to low quality of citrus wine and poor utilization rate of citrus varieties.In addition,due to the use of ordinary commercial wine yeast fermentation,there is no special strain for citrus wine,which makes the wine flavor relatively single,and the aroma complexity and characteristics are poor.In this paper,six citrus varieties mainly cultivated in Hunan were used as raw materials to select suitable citrus varieties for fermentation from the perspective of physical and chemical indexes,bitter substance content and flavor quality of citrus wine;The mixed fermentation of non Saccharomyces cerevisiae and common Saccharomyces cerevisiae with aroma enhancing ability was selected to explore the effects of different mixed fermentation on the volatile aroma components of citrus wine,in order to obtain the fermentation strains suitable for the fermentation of citrus wine and improve the aroma quality of citrus wine;The optimal mixed fermentation mode was compared with single strain fermentation,the changes of enzyme activity in different fermentation groups and its correlation with flavor substances were measured,and the aroma enhancement mechanism of mixed fermentation was discussed.The main results are as follows:1.The results showed that there were significant differences in the quality of fruit wine among different citrus varieties(P < 0.05).The bitter substances limonin and nomilin in Bingtang orange and blood orange wine Wenzhou orange,were higher;Langfeng navel orange wine has the lowest bitter substance content,the highest total phenol content and good quality in all aspects.There were significant differences in the content and types of aroma compounds in six wine samples.A total of 31 aroma components were measured in Langfeng navel orange,with the most types.The results of sensory evaluation showed that Langfeng navel orange wine had coordinated citrus fruit aroma and wine aroma,good flavor and taste,full-bodied wine,followed by fertile orange wine.Considering all aspects of quality,Langfeng navel orange was the most suitable for the processing of high-quality characteristic citrus wine.2.Using Kunfeng navel orange as raw material,the volatile aroma components of citrus wine obtained by different mixed bacteria fermentation are compared by GC-IMS technology.It was found that the fermentation of mixed bacteria would have a greater impact on the flavor of citrus cider.Different non-saccharomyces cerevisiae have a greater impact on the type and content of flavor substances.Compared with other fermentation groups,JW14+DV10 fermentation wine has a higher content of3-hydroxy-2-butanone,4-methylpentane-2-keto,butyral,valeraldehyde,ethyl acetate,ethyl propionate,isobutyl acetate,propyl acetate and propanoate,which can make the wine sample have soft fruit aromas such as banana and pineapple,as well as slightly fruity wine aromas.Sensory analysis showed that JW14+DV10 citrus wines were clear,crisp,aromatic,citrus fruity and fermented,with the best sensory quality.Based on the physical and chemical indicators,volatile aroma components and sensory evaluation,JW14+DV10 mixed bacteria fermentation citrus wine has better overall quality and better flavor,which is an effective way to increase the flavor characteristics of citrus cider.3.Using the fermentation strain strategy with the best flavor sense,taking the fermentation of single Saccharomyces cerevisiae and single non Saccharomyces cerevisiae as the control,the β-glycosidase,acid protease and volatile aroma substances after fermentation were measured respectively,and the correlation between enzyme activity and aroma substances was analyzed.The results showed that JW14 + DV10 had the highest enzyme activity,and the aroma of fruit wine was rich and higher.PLS was used to analyze the effect of enzyme activity of yeast on compound transformation during citrus wine fermentation.The results showed that there was a significant positive correlation between enzyme activity and the content of various aroma substances.