15E-10 |
Effect of germination on isoflavone contents in soybean |
J. S. KIM1, K. E. Yeo1, J. K. Kim1, G. B. Lee2, and W. J. Kim1. (1) Dept. of Food Science & Technology, Sejong Univ., 96 Gunjadong Kwangjingu, Seoul, 143-747, South Korea, (2) Goelbit Sengsikmaeul Co., Seoul, South Korea Isoflavone is one of the most important compounds found in soybean due to their effects as anticarcinogents, antioxidants and cholesterol-lowering agents. Fermentation, heat treatments and chemical and enzymatic hydrolysis were reported to cause changes in composition of isoflavone. However only a few works were repoerted on germination effects. The objective of this work was to study for changes in isoflavone during germination. The Korean varieties of soybean used in this work were Dawon, Taekwang, Geomjong-1, Myeongju-namul. The soybeans were soaked at room temperature for 10 hours and then germinated at 20 degrees C for 8 days under dark condition. The isoflavones determined by extraction with 80% ethanol and HPLC were diadzin, daidzein, genistin, genistein and total isoflavone. The highest isoflavone determined was 0.86 งท/g for Myeongju-namul which was followed by 0.55 งท/g for Taekwang, 0.44 งท/g for Dawon and 0.43 งท/g for Geomjong-1. The total isoflavone were generally increased after one day of germination followed by a slow decrease thereafter. The percents increased were in the range of 20-50%. Among the isoflavones, isoflavone aglycones of genistein and daidzein were most significantly increased by 200-300% while glycosides of genistein and daidzein increased relatively little. Myeongju-namul variety which showed the highest total isoflavone contents was most significantly increased to 1.30 งท/g after one day of germination. The ratio of genistin and genistein versus daidzin and daidzein were 100:60. The dry weight of soybean were decreased by appr. 10% after 8 days of germination. These results showed that germination of soybean could be a useful method for preparation of high isoflavone soybean products.
Session 15E, Nutraceuticals & Functional Foods I
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