Product Development And Technology Research Of Natural Sweet Wine

Natural sweet wine refers to the sugar content of wine more than 45g/L,and alcohol content?v/v?of wine more than 12%,respectively.Besides the remaining sugar in the wine,all the sugar for the yeast fermatation into alcohol completely sources from the grapes.the study aims to develop a kind of natural sweet wine,establish the proper technology and better fermatation conditions.the study started with the following aspects:1)screening the appropriate yeast to match the established process,2)figuring out the relationship of technology,yeast,wine,3)accumulating basic data for the industry of natural sweet wine.the results of the study are as follows:1)Selection of special yeast:the yeast strains from Saccharomyces cerevisiae preservated in the laboratory which can start the fermentation of grape juice with high sugar content,slow down the post-fermentation,and automatically terminate the fermentation.The minimum concentration 300g/L of substrate sugar was as a starting point,inoculated 16 strains of Saccharomyces cerevisiae by selected subspecies,then studied the ability of bacteria growth and fast starting up fermentation,selected two yeast strains S-4 and S-6 respectively,which grew well and quickly started fermentation under the sugar concentration of 400 g/L,the content of volatile acid produced by S-4 strain was low and the rate of post-fermentation of S-6 strain was slow,the former was suitable for the fermentation of grape juice with high sugar content,and the latter was suitable inhibiting fermentation in midway,thereby,further studied the physiological and biochemical characteristics of the two strains to confirm that they were suitable for brewing natural sweet wine.2)Improving sugar content of grape juice to brew natural sweet wine:Natural sweet wine was obtained in the conditions that the high-osmotic-pressure-resistance yeast fermented the grape juice of high sugar content and the remaining sugar content met to the necessary requirement of wine.This research raised the sugar content of grape pulp through concentrated grape juice before fermentation,then S-4 Saccharomyces cerevisiae was inoculated to start the fermentation,separated the yeast by centrifuging when residual sugar under 50 g/L,adding SO₂ and cooling storage to get the natural sweet wine.Compared with the strain of TOP15,the fermentation started rate and bacteria growth rate of S-4 were faster,the concentration of bacteria was higher and fermentation period was short,further more the bacteria decayed faster in post-fermentation.The primary liquor was clear and transparent,with typical ruby red colour,the fermented alcohol degree was14.3%?v/v?.3)Halfway inhibition fermentation process of natural sweet wine:stopped keeping sugar fermentation brewing natural sweet wine when halfway inhibition in fermented grape juice fermentation technology refers to the content of residual sugar to reach the required content.In this study,used the same batch of grape wine and brandy distillation system,and then used for fermentation halfway inhibitors.When natural sweet wine brewed,we used S-6 yeast fermentation to inhibit point centrifugal separation strains,and added the brandy.S-6 start fermentation fast and latter part was slowly in the Midway suppressed fermentation processes,so the fermentation process is easy to control.There detected 28 kinds of aroma components,The wine has better palatability and olfactory harmony.In conclusion,this study used the same batch of pre-made concentrated grape juice and distilled brandy,respectively adoped high sugar fermentation and halfway inhibition of fermentation process of making natural sweet wines,selected S-4 and S-6 customize saccharomyces cerevisiae,respectively applicable to different process are compared with goods all have unique advantages.Made from natural sweet wine has aroma balance and good taste.