Flavor deterioration of liquid endosperm in postharvest tender coconut revealed by LC-MS-based metabolomics, GC-IMS and E-tongue
Xiaojun Shen, Yuanyuan Wang, Ran Lu, Rui Liu, Xiwei Sun, Lanlan Hu, Yong Xiao, Fusheng Chen
Abstract
LC-MS-based non-targeted metabolomics , GC-IMS and E-tongue were employed to study the dynamical changes of the liquid endosperm , normally known as coconut water (CW), in postharvest coconut matured 8 months after full bloom. A total of 61 compounds was identified as differential metabolites responsible for metabolic changes during the whole storage (35 d at 25 ℃) using UPLC-MS/MS, whereas 8 volatiles were considered as the main components contributed to odor deterioration by GC-IMS. E-tongue data showed that bitterness response of CW was enhanced during storage, which was consistent with the variation of some bitter amino acids and epicatechin , while sweetness, sourness and umami exhibited an increased tendency except a decrease at 7 d due to the alteration of phenolic, amino acid, sugar and nucleotide. Postharvest storage displayed a distinct metabolic signature characterized by increased amino acid, nucleotide and sugar metabolisms. These results provided some new insights for biochemical changes of CW inside the postharvest coconuts.