숙성기간이 다른 재래식 된장 12종과 개량식 된장 4종의 아이소플라본과 $eta$-glucosidase 활성도를 비교하였다. 재래식 된장의 전체 아이소플라본 함량(TI)은 $370-723;{mu}g/g$이었고, 개량식 된장은 $179-537;{mu}g/g$으로 유의적으로 낮은 함량을 보였다. 된장의 주요 아이소플라본은 비배당체 형태였으며 재래식 된장의 경우 42.98-89.96%, 개량식 된장은 35.51-93.48%이었다. 아이소플라본 함량 분포에 대한 주성분 분석 결과 재래식 된장은 개량식 된장과 차별화가 가능하였다. 개량식 된장의 경우 $eta$-glucoside 형태는 검출되지 않았는데 이는 과도한 열처리를 받았거나 발효에 관여한 미생물의 $eta$-glucosidase 활성이 높았음을 의미한다. 된장시료에서 $eta$-glucosidase 활성도는 날콩에 비해 낮았으며 재래식 및 개량식 된장간에 유의적인 차이 및 아이소플라본의 분포와의 상관관계는 명확하지 않았다.
Isoflavone distribution and $eta$-glucosidase activity in 16 commercially available doenjang samples were determined. Twelve of the samples were home-made doenjang (HMD) with a relatively long fermentation period and 4 of the samples were factory-produced doenjang (FPD) from four different manufactures. Total isoflavones (TI) in the HMD ranged from $370-723;{mu}g/g$, while those in FPD ranged from $179-537;{mu}g/g$. The isoflavone distribution in HMD was different from those in FPD. Generally, the TI in HMD was higher than those in FPD. The major isoflavone was aglycones, which ranged from 42.98 to 89.96% in HMD and from 35.51 to 93.48% in FPD. Isoflavones in the $eta$-glucoside forms were not detected in tested FPD samples. Principal components analysis (PCA) of the isoflavone profiles showed that HMD were differentiated from FPD. First principal component (PC1) and second principal component (PC2) expressed 43.6 and 22.9% of the data variability, respectively. $eta$-Glucosidase activity in doenjang was lower than that in raw soybeans. The results of this study can be used to understand the differences in the isoflavone distribution in traditionally manufactured and factory produced doenjang.
