Metabolomics is an emerging research field based on exhaustive metabolite profiling that have been proven useful to facilitate the study of postharvest fruit development and ripening. Specifically, tracking changes to the metabolome as fruit ripens should provide important clues for understanding ripening mechanisms and identify bio-markers to improve post-harvest technology of fruits. This study conducted a time-course metabolome analysis in mangosteen, an economically important tropical fruit valued for its flavor. Mangosteen is a climacteric fruit that requires an important plant hormone ethylene to regulate ripening processes and rate. We first categorized mangosteen samples in different ripening stages based on color changes, an established indicator of ripening. Using gas chromatography/mass spectrometry, small hydrophilic metabolites were profiled from non-ripened to fully ripened (ripening stages 0-6). These metabolites were then correlated with color changes to verify their involvement mangosteen ripening. Our results suggest that the increase of 2-aminoisobutyric acid, psicose, and several amino acids (phenylalanine, valine, isoleucine, serine, and tyrosine) showed a correlation with the progression of mangosteen ripening. This is the first report of the application of non-targeted metabolomics in mangosteen. (C) 2017, The Society for Biotechnology, Japan. All rights reserved.