The Effects of Turning Fermentation Mixture on the Quality of Kaoliang Spirit

• Main Authors: Yeh, Ching-Chung, 葉慶鍾
• Other Authors: Weng, Yih-Ming
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/23546294255047729152

碩士 === 國立嘉義大學 === 食品科學暨生物藥學研究所 === 99 === Kao-liang liquor is a special alcoholic product manufactured by solid-state fermentation, thus many production operations will affect the qualities of the liquor. The present study was designed to investigate the effects of fermenting-grain-turning (FGT) technique on the quality of kao-liang liquor. The fermentation and distillation of each fermenting grain were conducted for three consecutive rounds which were carried out in both warm (ambient temperature above 28℃) and cold (ambient temperature below 22℃) seasons. The temperature and titratable acidity of fermenting grain and final alcohol concentration were significantly affected by FGT technique. For fermentation temperature during warm season, FGT decreased the fermentation temperature by increasing aeration. Since yeast alcohol fermentation is usually inhibited when temperature is above 38℃, the FGT showed less markedly effect on lowering temperature for cold season fermentation. The titratable acidity reached 25-30 ml/10 g in the first round and held relatively constant in the second and third rounds for the warm season fermentation. Because the acids did not distill and remained in the distilled materials, the following alcohol fermentation would be affected negatively by the acids. The acidity of non-FGT fermentation increased gradually from the first round to the third round with the final concentration approximately equal to the acidity of FGT counterpart. Less marked effects of FGT on titratable acidity were observed for fermentation conducted in the cold season. While alcohol concentration of FGT group was lower than that of non-FGT group for fermentation conducted in the warm season, no significant difference of alcohol concentration was detected between FGT and non-FGT groups fermented in the cold season. Since the overall alcohol yield of non-FGT fermentation was higher, the FT technique seems unnecessary in the respect of alcohol yield for solid state fermentation of kao-liang liquor. Total acidity, total ester and volatile components of FGT kao-liang liquor were significantly higher than those of non-FGT group; the difference was greater for liquor fermented in the warm season. However, no significant difference was detected in the sensory evaluation for kao-liang liquor derived from FGT and non-FGT groups.