Abstract
Natto's appearance, temperature, number/g of B. natto, hardness and color tone during fermentation were investigated at different temperatures (30, 35, 40, 45°C) with different inoculum sizes (102, 104, 106, cells/g). At a low temperature down with an decrease in inoculum size the fermentation rate was slowed. When the incubation temperature was high, Natto's temperature was also high. At higher temperatures and larger inoculum sizes, the growth rate of B. natto was faster. The hardness continued increasing through the 30 hours of fermentation, and showed higher values at higher temperatures and larger inoculum sizes. The change in Y% was opposite to those in x, y values. The z value increased during“gray green stage”. Natto's fermentation was kept in good conditions at 35°C with an inoculation of 104-106 cells/g or at 40°C·102-104 cells/g of the starter, judging from the appearance, color tone and hardness at 18-20 fermentation hours.
