| Xinjiang of China is the famous areas of grape planting and wine production in the world, and its table grapes have good quality. Because of table grapes production season more concentrating, there are a large number of grapes rotting away, and juicing and brewing is a good method to solve the contradiction. The biggest characteristic of natural low alcohol sweet wines is of rich nutrition, low alcohol, perfectly fruity taste, in harmony with sweet and sour,and fit for chinese diet habits, so low alcohol sweet wines is very promising as healthy drinks. This paper studied on using cell immobilized technology and inhibiting fermentation process in midway to brew low alcohol sweet wines, and providing references for the technology innovation of low-alcohol wine brewing. Several conclusions had been drawn in the experiments.1. From the grape resources of Shihezi areas screening a wine yeast strain F12 with the excellent performance of fermentation, through the strain morphology,physiological and biochemical characteristics and molecular taxonomy test, the yeast was determined to be of S.cerevisiae. The result of testing the capability of fermentationshowed that the wine yeast's propagation and growth was fast, the ability of fermentation was powerful, The ability of adapting to grape juice was strong. The F12 yeast could ferment the grape juice with sugar content above 400g/L, SO2 concentration above 200mg/L, alcoholic content above 15%, acid content 18g/L. It could ferment in the temperature range of 10-35℃. The F12 yeast is closer to the French wine yeast D254 in the speed and ability of fermentationin. The wine brewing by the F12 yeast has tne characteristics of pure color, aroma full-bodied wine, mouth-filling, coordination and pure and gentle to taste, in the brewing performance without too much difference with the French wine yeast D254.2.Through using the technique of immobilization cell, Sodium alginate-PVA mixed was used for Saccharomyces cerevisiae immobilization.The fermentation performance and mechanical intensity of immobilized S.cerevisiae under different conditions were determined and optimized to improve characteristics of the carrier, the results showed that 2% sodium alginate and 7% of PVA mixed as the carrier, with 4% calcium chloride solution as crosslinking agent curing 6h at room temperature, so the characteristics of the carrier is better; while comparing the fermentation performance of immobilized yeast and free yeast and winemaking experiment, the results showed that S.cerevisiae could grow well in the carrier, and the total bacterial count could reach at 109 series, immobilized yeast got the wine, residual sugar 3.34 g/L,alcohol 10.2°,free yeast got the wine, residual sugar 3.71 g/L,alcohol 10.0°, both almost there.3. Determined the brewing optimal process of low alcohol sweet wines:table grape was removed its stems and broken, adding in SO2 content 100mg/L, going to 45℃,60min hot-soaking pretreatment, adding in 15%(v/v) immobilized yeast and fermenting at 18-20℃constant temperature, after fermenting 108-120h, when alcoholic strength reached to 5-7°,immobilized yeast was filtered out of the wine, then centrifuging the wine by 6000r/min,15min, taking the fluid to go to diatomite filtration, then adding in SO2 content 100mg/L could get low alcohol sweet wines. |
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