High Performance Liquid Chromatographic Analysis of Isoflavones in Soybean Foods

콩 종류와 대두 가공식품에 함유된 isoflavones의 정량

  • Kim, Chung-Sook (Department of Herbal Medicine, Korea Institute of Oriental Medicine) ;
  • Lee, Young-Sun (Department of Herbal Medicine, Korea Institute of Oriental Medicine) ;
  • Kim, Jin-Sook (Department of Herbal Medicine, Korea Institute of Oriental Medicine) ;
  • Han, Young-Hee (Department of Chemistry, Sangmyung University)
  • Published : 2000.02.28

Abstract

Phytoestrogen has been used as a suppliment of estrogen in order to treat osteoporosis. The representative phytoestrogens, isoflavones, are daidzein, genistein and formononetin which were present highly in our traditional soybean foods. The quantitative analysis of the isoflavone was done with a high performance liquid chromatography(HPLC) using a UV/VIS detector for the contents of the isoflavones in Astragali Radix, soybean sprouts, bean-curd(Tofu), soybean, soybean oil, pea, kidney pea, black bean(Yak-kong), soybean sauce(Ganjang). soybean paste(Doenjang), and fermented soybean(Maejoo). The content of free daidzein in soybean sprouts was $43.49{\pm}3.41\;mg/kg$$ which was much higher than that in soybean, $14.52{\pm}0.58\;mg/kg$, although total daidzein of fermented soybean was lower than that in soybean (Table 2. P<0.01). The amounts of free genistein in soybean sprouts, fermented soybean. and soybean paste were $27.63{\pm}1.66\;mg/kg,\;291.52{\pm}6.81\;mg/kg,\;and\;18.75{\pm}1.33\;mg/kg$, respectively. The level of free formononetin in soybean paste was the highest among the soybean products (P<0.01). The content of formononetin in Aatragali Radix, $9629.73{\pm}0.57\;{\mu}g/kg$, was about 160 times higher than that in soybean. Thus Korean traditional soybean products, black bean(Yak-Kong) and Astragali Radix can be a good choice of phytoestrogens.

콩에 함유되어 있는 이소플라본은 골다공증 예방 및 치료제로써의 활발한 연구가 진행중이다. 콩은 우리의 식생활과 깊은 관련성이 있으므로 이소플라본의 함량을 HPLC로 정량분석 하였다. 한국산 황기와 콩제품인 콩나물, 두부, 콩기름, 메주, 된장, 간장, 대두, 약콩, 완두콩 및 강남콩 등에서 함유된 isoflavone을 5mM $NaH_2PO_4$ 완충용액(pH 4.6)과 메탄올을 혼합한 이동상 (4 : 6) UV 260 nm에서 분석하였다(Table 2). 콩식품에 함유된 isoflavone중 유리 daidzein 양은 콩나물에서 $43.49{\pm}3.41\;mg/kg$, 된장에서 $233.31{\pm}5.81\;mg/kg$, 약콩은 $35.66{\pm}4.70\;mg/kg$이 검출되어 대두 $(14.52{\pm}0.58\;mg/kg)$ 비해 높았다. (P<0.05)간장 및 콩 기름은 함량이 낮았고, 완두콩 및 강남콩의 함량은 측정치 이하였다. 유리 genistein은 콩나물이 $27.631{\pm}1.66\;mg/kg$,메주가 $18.75{\pm}1.33mg/kg$, 된장이 $291.52{\pm}6.81\;mg/kg$ 검출되었고, 대두는 $22.49{\pm}0.93mg/kg$으로 약콩$(61.10{\pm}7.73mg/kg)$ 보다 낮았다(P<0.01). 그러나 formononetin의 함량은 daidzein, genistein과는 다른 양상을 보였으며, 특히 황기는 daidzein과 genistein은 검출되지 않았으나 formononetin의 함량이 대두$(60.62{\pm}11.35\;{\mu}g/kg)$ 비해 $9629.73{\pm}0.57\;{\mu}g/kg$으로 약 160배 이상 많았고, 약콩은 대두와 유사하였으나, 콩기름, 완두콩, 강남콩에서는 formononetin이 검출되지 않았으며, 전통식품인 된장과 메주에도 상당량 함유되어 있었다.

Keywords