1. Dept. of Food Science, College of Food Science and Engineering; Jilin Univ.; Changchun Jilin 130062 China
2. Dept. of Nutrition and Food Sciences, College of Agriculture and Life Sciences; Univ. of Vermont; Burlington Vt. 05405 U.S.A
3. Dept. of Food Science; Northeast Agriculture Univ.; Harbin Heilongjiang 150030 China