1. College of Food Science; Sichuan Agricultural Univ.; Ya'an 625014 Sichuan China
2. Natl. Engineering and Technology Research Center for Fruits and Vegetables; College of Food Science and Nutritional Engineering, China Agricultural Univ.; Beijing 100083 China
3. Dept. of Food Science and Technology; Faculty of Agriculture, Assiut Univ.; Assiut 71526 Egypt