1. Graduate Institute of Food Science and Technology, National Taiwan University, Taipei 106-17, Taiwan, Department of Bioindustry Technology, Dayeh University, 112 Shan-Jiau Road, Da-Tsuen, Chang-hua 515, Taiwan, and Department of Radiation Oncology, Mackay Memorial Hospital, 45 Minsheng Road, Tamshui, Taipei County 251, Taiwan