This study was conducted to examine the changes of pH, proteolytic enzymic activity, and every kind of nitrogen compounds during their fermentation of the three groups of meju for 90days.
Among the three groups, the first group was conventional Korean meju which was proved to be good quality (sample J), the second group was prepared with soybean paste using B. subtilis (sample K), and the third group was an improved meju which was fermented with the soybean and wheat (7 : 3) mixtured paste with Asp. sojae (sample L).
These groups were analyzed at an interval of 10 day and the results are summarized as follows:
1) The pH of the all three groups was lowered from 6.45∼6.75 to 4.85∼5.20 in just the 30 days and maintained the weak acidity during this fermentation.
2) The proteolytic enzymic activity was increased as soon as the three groups of meju were fermented and marked the maximum value in 30 days. The maximum value of the three groups of meju J.K. and L was 147, 112, and 52 respectively. The proteolytic enzymic activity of sample J and K was decreased to 23.5 and 20.5 in 20 days, while that of sample L was decreased to 18.0 in 40 days, and maintained the volues to the end of fermentation for 90 days.
The conventional meju J and the improved meju K showed sparkling activity at the pH 7, while the activity of improved meju L was strong at the pH 10.
3) The PAA-N content of sample J and K was increased and reached to the peak point with 1.55% and 1.49% respectively in 60 days. But the sample L marked the maximum value with 1.28% after 80 days.
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