Research of the changes of sugar and ethanol contents during ice wine brewing process

The main chemical constituents of ice wine changed significantly in the process of brewing,especially during main fermentation.These changes,including sugar's consumption and ethanol's production,had important influence on the quality of ice wine.This study took Vidal ice grape juice provided by Wunvshan Milan Wine Co.Ltd as material and inoculates Yeast( ST) to ferment.After fermentation,the ice grape juice was storaged in oak barrel for ageing which lasted 4 months.The changes of sugar and ethanol contents during fermentation and ageing were determined by HPLC- ELSD.Sensory evaluation of flavor and microorganisms were detected after the completion of the brewing.The results showed that main sugars in ice grape juice were glucose and fructose.During the process of fermentation,the glucose content in the ice wine decreased from 180.56 g / L to 53.24 g / L,what's more,the period from 7 to 28 days had highest decline rate. Fructose content in the ice wine decreased from 223.65 g / L to160.54 g / L.And the changes of ethanol concentration were negatively correlated with changes in glucose content,the final alcoholic degree was 11% v / v. During the process of ageing in oak barrel,the glucose content in the ice wine decreased to 47.64 g / L.The fructose content decreased to 151.25 g / L,while final alcoholic degree was 9.8%v / v.Microbial detection and flavor assessment were in line with the standard. The research provided theoretical basis for improving the processing technique and quality of ice wine,at the same time laid a foundation for identification of ice wine.