**Melatonin from different fruit sources, functional roles, and analytical methods
a Beijing Research Center for Agricultural Standards and Testing, Room 703, Block A, Beijing Agricultural Building, Beijing Academy of Agriculture and Forestry Sciences, Middle Road of Shuguanghuayuan, Haidian Dist., Beijing 100097, PR China
b Department of Food Science & Technology, Oregon State University, Corvallis, OR 97331-6602, USA