Analysis Of The Higher Alcohols In Grape Wine And Method Of Regulating And Controlling It

The environmental factors including strains and inoculum concentration of yeast, a -amido nitrogen concentration in grape musts,fermentation tenperature and pH of the musts were studied and were demonstrated in relation to the content of higher alcohols produced during alcoholic fermentation in grape wine of Jufeng. A method of super area-external standard of Capillary Gas Chromatography was established for analyzing the higher alcohols in grape wine. In addition, a sensory evaluation revealed a proper range of content of higher alcohols in grape wine.The environmental factors including strains and inoculum concentration of yeast, a -amido nitrogen concentration in grape musts,fermentation tenperature and pH of the musts were tested and were demonstrated in relation to the content of higher alcohols produced during alcoholic fermentation in grape wine of Jufeng.And the results confirmed that a remarkable variability of higher alcohols content occurs in the production brewed by the different yeast strains.For one single strain,different inoculum concentration generate different amount of higher alcohols in the vinification.The strain Y1 is suitable for the higher alcohols content in the wine and is lower than other strains after fermentation.Increasing the inoculum concentration of Yl in the grape musts properly contributed to lesser higher alcohols content too. The results were also show that total higher alcohols decreased when addition simple organic amino nitrogen or inorganic amino nitrogen to a range of 180~200mg/L a - amino nitrogen in the grape musts.The lower fermentation temperature and lower pH of grape juice give rise to the decreasing the amount of higher alcohols. There seemed to be a relationship between addition Leu to grape musts and higher isoamyl alcohol concentration in the products and between addition Val to grape musts and higher isobutyl alcohol concentration.The relationship showed that the better the grape is the more higher alcohols generated and the more necessary to control the fermentation processs.Optimum environmental factors of brewing processing were gained by orthogonal test.The range analysis proved that,among the four environmental factors above,the factor influencing the higher alcohols concentration in the product of grape wine most is the content of a - amino nitrogen in the grape musts,the second is inoculum concentration of yeast,the third , fermentation temperature and the last is primitive pH value in grape must.