Abstract
The components and microorganism growth differed during putrefactive fermentation and normal fermentation. In putrefactive fermentation yeast reached a maximum of 8×106 cells per ml of Moromi Mash in two days of fermentation. Lactic acid bacteria increased to 1×108 cells per ml of Moromi Mash after 6 days of fermentation, and thereafter decreased rapidly. Under normal fermentation yeast increased to 2.7×108 cells per ml of Moromi Mash after 4 days fermentation and then decreased. No lactic acid bacteria was observed.
In normal fermentation less acetaldehyde was formed than in putrefactive fermentation (about half). However in the latter, higher alcohols (C3_??_C5) and ethyl acetate were formed (about 1.5- to 2-fold). Isoamyl acetate, a fragrant component found in normal fermentation, was not formed under putrefactive fermentation.
When the Moromi Mash was putrefied, the total lactic acid and acetic acid was about 90% of the total organic acids, and the content of citric acid was 4%. Lactic acid and acetic acid increased gradually with fermentation time. On the other hand, in normal fermentation citric acid was the main acidic component, and it accounted for 59.2% of all organic acids, with malic acid the next most common acid (17.8%). In putrefactive fermentation the amount of malic acid was considerably lower than under normal fermentation but the amount of formic acid was greater than in normal fermentation.
