1. Department of Food and Nutrition, Sunchon National University, Suncheon 540-742, Korea, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-18 Korea, Department of Environ Biotechnology, Gyeongsang National University, Chinju 660-701, Korea, and Department of Bioscience and Biotechnology, Kyushu University, Fukuoka 812-8581 Japan