Enzyme inactivation and quality preservation of sake [Japanese alcoholic bevera from rice] by high-pressure carbonation at a moderate temperature

The effect of a high-pressure carbonation treatment on the change in quality of sake during storage was investigated. Measurements of the amino acidity and isovaleraldehyde content of carbonated sake (20 MPa pressure at 40, 45 and 50 deg C for 7, 21 and 33 min, respectively) as well as of heat-treated sake (reaching temperature of 65 deg C and immediately cooled) were almost unchanged during storage at 3 and 20 deg C. Glucose in the sake subjected to these treatments was retained at an almost constant under the same storage conditions, except for the sake carbonated at 40 deg C and stored at 20 deg C. In contrast, the amino acidity, and glucose and isovaleraldehyde contents of non-pasteurized (fresh) sake increased during storage at both temperatures. The sake samples subjected to the carbonation treatment and heat treatment both gave better sensory scores than the fresh sake sample after 6 month of storage at 3 and 20 deg C, especially at 3 deg C for the flavor. These results suggest that the high-pressure carbonation treatment is an effective new technique for preserving the quality of sake.