1. Department of Food Science and Technology, Dongguk University, 3-26 Pil-dong, Chung-gu, Seoul 100-715, Korea; Department of Environmental Toxicology, University of California, Davis, California 95616; Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Albany, California 94710; and School of Agricultural Biotechnology, Seoul National University, Seoul 151-742, Korea