1. Department of Food and Biotechnology, Korea University, Chungnam 339-700, Korea
2. Dairy Science Division, National Institute of Animal Science, Chungnam 331-800, Korea
3. Department of Animal Science and Technology, Chung-Ang University, Gyeonggi 456-756, Korea
4. Department of Food and Nutrition, Korea University, Seoul 136-703, Korea
5. Department of Brain Education, University of Brain Education, Chungnam 330-841, Korea