ホスファターゼ低生産麹菌株kbn8048を用いた非加熱だし入り米味噌のイノシン酸分解特性

Abstract

__________________We applied the low acid phosphatase producer Aspergillus oryzae KBN8048 or its mutants to non-heated soybean paste. In a rice koji trial, acid phosphatase activity was lower than that of A. oryzae EM-2, a market strain for miso brewing, when sodium phosphate concentrations up to 20 mM were added at the beginning of incubation. The soybean paste was brewed at 30 °C for 60 days, using rice koji, followed by the addition of 0.2 % inosinic acid and incubation at 4 °C. The inosinic acid required 7 weeks and 1 week to decrease by 50 % with KBN8048 and EM-2, respectively. When KBN8048 was incubated at 30 °C for 1 week, more inosinic acid was retained than when the same was done using EM-2. These observations indicate that addition of A. oryzae KBN8048 strains to non-heated soybean paste was effective for inhibiting the degradation of inosinic acid.