국내 전통발효식품으로부터 protease 활성이 높은 Aspergillus oryzae SCF-6, SCF-37, 그리고 JJSF-1 균주를 선발하여 된장을 각각 제조하고 60일간 숙성하면서 품질을 비교 평가하였다. 60일 숙성 동안 수분 염도 및 pH는 시료 간에 큰 차이가 없었다. 된장의 숙성지표가 되는 아미노산성 질소의 함량은 숙성 경과에 따라 증가하여 60일 숙성 후 SCF-6을 활용하여 제조한 된장이 971.6 mg%로 다른 시료보다 높았으며, 유리아미노산 함량도 상대적으로 높은 8,064.9 mg%이었다. SCF-6과 37로 제조한 된장은 60일 숙성 후 GABA 함량이 각각 61.3과 53.7 mg%로 측정되었다. 색도는 숙성 경과에 따라 명도와 황색도는 점차 감소한 반면 적색도는 점차 증가 하였다. 아플라톡신은 모든 된장에서 불검출 되었고, 바이오제닉 아민 중 histamine 함량은 2.55-5.60 mg/kg 그리고 tyramine은 3.70-5.87 mg/kg으로 매우 낮게 측정되었다. 본 결과로 A. oryzae SCF-6은 장류 제조의 종균으로 적합한 것으로 판단된다.

This study was conducted to evaluate the possible utility of 3 Aspergillus oryzae strains (designated as SCF- 6, SCF-37, and JJSH-1), isolated from Korean traditional fermented materials, as starter cultures in the soybean paste industry. Doenjang (fermented soybean paste) was made with the A. oryzae strains described above, and its quality attributes were analyzed during a 60-day aging period. No significant differences in pH, moisture, or salt content were detected among the doenjang varieties made with the 3 Aspergillus strains. The concentration of amino-nitrogen, an indicator of doenjang aging, increased in each sample during the aging period. After the 60-day aging period, the contents of amino-nitrogen and free amino acid in doenjang made with SCF-6 showed the highest concentrations among the tested doenjang products: 971.6 and 8,064.9 mg%, respectively. Measurements of the color of doenjang showed that lightness and yellowness decreased during the aging period, but redness increased. After the 60-day aging period, the γ-aminobutyric-n-acid (GABA) concentrations in doenjang made with SCF-6 and SCF-37 were 61.3 and 53.7 mg%, respectively. In doenjang samples, aflatoxin was not detected and the concentrations of biogenic amines (histamine and tyramine) were 2.55-5.60 mg/kg and 3.70-5.87 mg/kg, respectively. These results indicated that A. oryzae SCF-6 isolated from traditional fermented foods could be useful as a starter culture in the soybean paste industry.