잠재적인 생균제제 Bacillus subtilis CSY191에 의해 제조된 국산 검정콩(서리태 및 서목태) 청국장 발효 중 ${eta}$-glycosidase 활성, total phenolic와 isoflavone 함량 및 항산화 활성을 조사하였다. 청국장 발효 후 total phenolic 및 isoflavone-malonylgycoside와 -aglycone 함량은 증가하였고 이에 따라 ABTS 라디칼 소거활성 및 FRAP 활성은 증가하였으나 isoflavone-glycoside 함량은 감소하였다. 특히, $7^{circ}C$에서 48시간 발효된 서리태 청국장은 서목태 원료 및 청국장보다 높은 활성을 나타내었다. 서리태 48시간 발효 후, daidzein, glycitein 및 genistein의 함량은 각각 253.0 ${mu}g/g$ 72.5 ${mu}g/g$ 및 114.1 ${mu}g/g$을 나타내었다. 이 결과로부터, 검정콩 청국장의 높은 항산화 활성은 total phenolic 및 isoflavonemalonylgycoside와 -aglycone 함량 증가에 의한 것으로 추측할 수 있다.
Changes in ${eta}$-glycosidase activity, total phenolic and isoflavone contents, and antioxidant activities during the fermentation of Korean black soybeans (Seoritae and Seomoktae) fermented food cheonggukjang by the potential probiotic Bacillus subtilis CSY191 were investigated. The levels of total phenolic and isoflavone-malonylglycoside and -aglycone contents increased, while 2,2-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging activity and ferric reducing/antioxidant power (FRAP) increased, but the isoflavone-glycoside contents decreased after cheonggukjang fermentation. The content of antioxidant compounds, including isoflavone-aglycones and -malonylglycosides, was increased by fermenting-processing, whereas the content of isoflavone-glycosides was decreased in the fermented soybeans. In particular, the Seoritae soybean fermented at 3 $7^{circ}C$ for 48 h displayed the highest antioxidant activities, compared to those of the Seomoktae soybean and the fermented. The highest levels of daidzein, glycitein, and genistein were present at concentrations of 253.0 ${mu}g/g$, 72.5 ${mu}g/g$, and 114.1 ${mu}g/g$ after 48 h of Seoritae soybean fermentation. From those results, we suggest that the high antioxidant activity of cheonggukjang of black soybeans might be related to the markedly higher levels of total phenolic and isoflavone-aglycone and -malonylglycoside contents achieved during fermentation.
