1990 Volume 85 Issue 2 Pages 114-119
Fermentation characteristics of sake mash made by rice-koji prepared with Aspergillus kawachii were investigated for the purpose of obtaining sake with a flavor of citric acid. During the preparation of rice-koji, the temperature at the latter half of cultivation was kept at 40°C, so that not so much amount (8.3 mg/g koji) of citric acid was produced by A. kawachii. Activities of α-amylase and acid protease of the rice-koji were 1/16 and 2.6 times, respectively, those of rice-koji prepared with A. or yzae used in common sake brewing. The extremely low activity of α-amylase gave little influence on the parallel fermentation, that is, the combination of progressive saccharification of starch in raw materials and alcohol fermentation in sake mash. This result was considered to be due to the fact that α-amylase of A. kawachii was not adsorbed on steamed rice, because the a-amylase adsorbed was quite inactive in attacking the steamed rice on which the enzyme had been adsorbed, and had an important effect on the digestion of steamed rice in the early stage of sake mash. The quality of sake brewed with rice-koji of A. kawachii had fresh flavor and sour taste of citric acid in sensory evaluation.
