Natural Brewing Process Of Muscat Wine And The Screening, Identify Of Yeast And Their Characteristic Analysis

In this study, the natural brewing process of muscat wine was analyzed.Compared to that of brewing process with commercial yeast, the common physical and chemical indicators, aroma compounds and their characteristics of Muscat wine from natural brewing process was studied, which will provide theory basis for the production of Muscat wine with regional and variety characteristics.At the same time, functional yeast, which play important role in the natural brewing process, was screened and identified. Furthermore, their function in the brewing process was also studied in the case of finding yeasts that fit the regional characteristic of Changli and the variety features of Muscat grape. The results are as follows:1. Compared to the brewing process with commercial yeast, the characteristics of natural brewing process of Muscat wine are as follows: the initiation of alcohol fermentation of natural brewing process is 2 days later, and 8days is needed to finish the alcohol fermentation, which is 2 days longer than the control, and all of the final physical and chemical indicators of it meet the criterion GB/T15037-2006 and brewing qualification. In case of the total acid content, it reached a content of 4.8g/L after 2 months sat quietly, which 0.565 g/L lower than that of the control. Moreover, there no menthol was detected and it was concerned as secure. Finally, there no obvious difference in the components of phenolic compounds between these two brewing process, but the Muscat wine from natural brewing process took an advantages of phenolic compounds amount.2. There were 46 kinds of aroma compounds in total were detected in the Muscat wine from natural brewing process after alcohol fermentation, the content of phenethyl alcohol,nerol,ethyl caproate,etheyl octanoa, and so on, which are the characteristic flavor compounds for Muscat grape, were high relatively. And at the same time, it is in advantage of the kinds of aroma compounds and the content of them than that of wine from brewing process with yeast FX10.3. There were 7 yeast strains were screened from the brewing broth during the alcohol fermentation in the natural brewing case, and 2 of them, named as Y1 and Y2, were identified molecularly as saccharomyces cerevisiae, 1 of them,named as Y3, was identified molecularly as Spore Hanxun yeast. Ethanol tolerance of strain Y1, Y2 and Y3 was 14%,10% and 16%, respectively. Moreover,all of these three yeast strains can produce high content of esters, especially for strain Y2.4. In the fermentation experiments, the results of reducing sugar measurement indicated that strainY1, Y2 and Y3 meet the criterion for dry red wine production. Strain Y1 showed the best ability in alcohol production, and strain Y2 produced more total acid and volatile acid content than strain Y1 and Y3did; Moreover, each single strain produce more volatile acid content than the mixture strain of Y1, Y2 and Y3 did. Furthermore, there are 42,32,50 and 22 kinds of aroma compounds were detected in the broth of Y1, Y2, Y3 and the mixture strain of them. And the results indicated that strain Y1 and Y2 performed better in fermentation than strainY2 and the mixture strain did, but Y2 showed a high ability in ester production. Base on above, mixture strain performed not as well as single strain did in fermentation experiments.