1. Department of Life and Food Sciences, Obihiro University of Agriculture and Veterinary Medicine, West 2-11, Inada-cho, Obihiro, Hokkaido 080-8555, Japan
2. Kamikawa Taisetsu Sake Brewery Co., Ltd., Kamikawa-cho, Hokkaido 078-1761, Japan
3. Vegetable Crops Research Unit, USDA-ARS, Department of Food Science, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA