청육장은 볶은 대두를 이용하여 제조된 청국장에 해산물, 육류를 함께 가열한 반가 식품의 일종이다. 140과 220$^{circ}C$에서 각각 21.0과 6.0분 간 볶은 대두와 이를 이용한 청국장, 청육장의 총 아이소플라본을 HPLC로 분석하였다. 총 아이소플라본 함량(${mu}$mol/g)은 생 대두 대비 약 79-80, 56-65, 47-50%이었다. 볶음 공정으로 인해 malonyl-${eta}$-glucosides 함량은 유의적으로 감소한 반면 acetyl-${eta}$-glucosides와 ${eta}$-glucosides의 함량은 유의적으로 증가하였다(p<0.05). 청국장과 청육장의 주된 아이소플라본은 ${eta}$-glucosides 이었다. 생 대두와 볶은 대두에서는 succinyl-${eta}$-daidzin과 succinyl-${eta}$-genistin은 검출되지 않았고, 청국장과 청육장에서 succinyl-${eta}$-genistin의 peak area는 succinyl-${eta}$-daidzin 보다 더 높게 검출되었다.
Cheongyukjang, a Banga food, is a heavy soy-soup prepared by boiling cheonggukjang, sea foods, and meats. Soybeans roasted at 140$^{circ}C$ for 21.0 min and 220$^{circ}C$ for 6.0 min, respectively, were used for cheonggukjang preparation. Distributions of isoflavones in raw soybeans, roasted soybeans, cheonggukjang, and cheongyukjang were analyzed by high performance liquid chromatography. The total isoflavones in roasted soybeans, cheonggukjang and cheongyukjang were about 79-80, 56-65, and 47-50% of those in raw soybeans, respectively. Roasting caused significant increases in acetyl derivatives and ${eta}$-glucoside isoflavones, and significant decreases in malonyl derivatives (p < 0.05). The major isoflavones in cheonggukjang and cheongyukjang were ${eta}$-glucosides. Succinyl-${eta}$-daidzin and succinyl-${eta}$-genistin, which are recognized as new metabolites of isoflavones, were not detected in raw and roasted soybeans. Peak areas of succinyl-${eta}$-genistin were higher than thse of succinyl-${eta}$-daidzin, in both cheongyukjang and cheonggukjang.
