Metabolite profiling of Indonesian cacao using gas chromatography-mass spectrometry

Indonesia as the world third largest cacao producer is also well known for its fine cacao from Trinitario group. Fine cacao breeding will support the sustainability of Indonesian specialty cocoa products. However, information on the distinction between metabolite profile of Indonesian fine and bulk cacao are still limited. The objective of this study was to compare the metabolite profile of Indonesian fine and bulk cacaos using Gas Chromatography-Mass Spectrometry (GC-MS) method with methanol-formic acid-water extraction. Four Indonesian fine cacaos (i.e. DR 2, DRC 16, PNT 16, PNT 17) and bulk cacaos (i.e. MCC 02, KW 516, KW 617, SUL 01) were used. Measurements were conducted on untargeted metabolite profile, theobromine (T), caffeine (C), T/C and total fat content. Forty-nine peaks were detected and 23 putative metabolites with high reliability were identified. Principal component analysis separated fine and bulk cacaos into two different groups. Hierarchical cluster analysis showed fine cacaos contained higher caffeine while bulk cacaos contained higher fatty acids (palmitic acid, stearic acid and oleic acid) content than the opposite. However only fatty acids, which represented in total fat content, showed stable result under targeted analysis. Therefore, these metabolites could be further analysed as biomarker for fine cacao selection.