[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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Recently (after 1990), we attempted to isolate lactic acid bacteria from koji, seed mash (moto or shubo), main mash (moromi), and sake. Most lactic acid bacteria are unsuited for sake brewing in developing moromi with excessive acid accompanied by an off flavor due to acetic acid and diacetyl.
We isolated lactic acid bacteria from 24 samples: 2 strains from koji, 1 from brewing water, 2 from shubo, 7 from moromi, 1 from stored sake in a brewery, and 11 from sake in the market. These bacteria were all bacilli except for 1 bacterium (coccus) isolated from a koji.
On the natures of these strains: Thirteen srains were lactic acid bacteria having homo fermentation, and 11 strains had hetero fermentation. Twenty two strains were able to grow in 10% alcohol containing a medium (BCG or SI medium). The strains which produced diacetyl at more than its detectable threshold comprised only about 1/3 of the total. It was confirmed that strain No.8 was able to convert more than 99% of its malic acid to lactic acid. We concluded that the strain was of malo-lactic fermentation bacteria which were isolated from the main mash prepared with yamahaimoto seed mash.
Strain No.8 was identified as Lactobacillus paracasei by the similarity of its 16S rRNA sequence to that of related Lactobacilli.

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Ethyl carbamate, known for its genotoxicity, is found in a wide range of fermented foods and alcoholic beverages. We attempted to reduce ethyl carbamate in ume liqueur by the removal of hydrogen cyanide - which is a precursor of ethyl carbamate - using soda lime. Ume liqueurs were steeped by stirring under the conditions of placing soda lime in the headspace. The ethyl carbamate and hydrogen cyanide concentrations in the experimental groups were reduced by 70% and 79%, respectively, as compared with the control group. There were no significant differences between the control and experimental groups in alcohol content, specific gravity, pH, total acidity, or sensory evaluation.

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