Comprehensive Measurement and Comparison of Ionic Small Molecules Contained in Citrus Unshiu Marc. Using Metabolomic Analysis

Few studies have comprehensively screened for ionic small molecules with high water-solubility in the traditional Japanese mandarin orange Citrus unshiu Marc. Here, we performed metabolomic analysis with capillary electrophoresis-mass spectrometry (CE-MS) to comprehensively identify and accumulate gross quantitative data for water-soluble components in the different varieties of 'Aoshima' and 'Okitsu/Miyagawa Wase', according to grade and processing method. In this analysis, we focused on 151 components and showed the characteristic components related to each different variety and processing method, e.g., Met, Gly, and Asp in var. Wase; ornithine, putrescine, synephrine, and Gln in var. Aoshima; and pyroglutamate, GABA (gamma-aminobutyric acid), and malonate in the juice of var. Aoshima. Furthermore, we conducted processing tests and identified components that were affected by squeezing or heating. These data represent basic data for further investigation of the metabolism of C. unshiu Marc. or chemical changes in their components due to external factors such as processing.