18B-26 |
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E.-K. BAIK, Dept. Food Science and Biotechnology, Kyung Hee Univ., 1 Seochun, Yongin, 449-701, South Korea, K.-S. Kim, Dept. of Food Science and Technology, KyungHee Univ., 1 Seocheon-ri, Kiheung, Yongin, 449-701, South Korea, C.-S. Park, Dept. of Food Science and Technology, KyungHee Univ., 1 Secheon-Ri, Kiheung, Yongin, 449-701, South Korea, K.-H. Park, Dept. of Food Science and Technology, Seoul National Univ., School of Agricultural Biotechnology, San 56-1, Silim-dong, Kwanak-gu, Seoul, 151-742, South Korea, and M.-Y. Baik, Dept. of Food Science and Technology, KyungHee Univ., Seochun 1, Yongin, 449-701, South Korea. Isoflavones are widely recognized for their potential health benefits. The increased use in various food products calls for the assessment of their thermal stability. Most soy foods contain 6 to 10% of the isoflavones of whole soybeans and many researches have been done on the thermal stability of soy isoflavones. Although kudzu root contains almost same amount of isoflavones compared to soybean, limited information is available on thermal stability of kudzu root isoflavone. Therefore, in this study, effect of heat processing on thermal stability of kudzu root isoflavone was investigated for future use of kudzu root isoflavone. The objective of this work is to investigate the thermal stability of kudzu root isoflavones for future use in various processed foods and neutraceuticals. Kudzu root extracts were heated at 80, 100, 121, 140, 165, 180 oC for up to 90 min. before and after concentration, respectively. Changes in the amount of isoflavones were monitored using HPLC and thermal stability was investigated using arrhenius equation. The amount of both daidzin and genistin does not significantly decrease during heating at 80,100 and 121 oC but decreases significantly above 140 oC. This indicates that daidzin and genistin are stable at temperatures near the boiling point of water. The degradation of both daidzin and genistin occurred in 2 steps and each step showed typical first order kinetic. The degradation rates were faster in first step than second step in both daidzin and genistin. Additionally, the degradation was accelerated when they heated after concentration compared to the sample heated before concentration. These results suggested that degradation of kudzu root isoflavones was highly depend on both their concentration and heating temperature. This study provides the basic information on thermal stability of kudzu root isoflavones, which can be used for future processing of functional foods.
Session 18B, Food Chemistry: Antioxidant and bioactive agents
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |