1. Department of Food Science and Human Nutrition, and Center for Healthcare Technology Development, Chonbuk National University, Jeonju, Jeonbuk, 561-756, Korea.
2. Corresponding author. Phone: +82-63-270-3857. Fax: +82-63-270-3854. E-mail: keum@chonbuk.ac.kr
3. Department of Biological Systems Engineering, University of Nebraska, Lincoln, NE 68583.