1. Department of Food Science, University of Arkansas, Fayetteville, AR 72704.
2. Current address: Department of Nutrition and Food Science, Fu-Jen University, 510 Chung Cheng Rd, Taipei, Taiwan.
3. Corresponding author. Phone: 479-575-3871. Fax: 479-575-6936. E-mail: yjwang@ uark.edu