Localization analysis of multiple vitamins in dried persimmon (Diospyros kaki) using matrix-assisted laser desorption/ionization mass spectrometry imaging

Abstract

The drying process used for persimmon fruit (Diospyros kaki) can alter the composition of nutrients, and especially vitamins. We visually determined whether the amounts of vitamin A1, vitamin B6 and vitamin C vary after drying persimmon fruit, using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) imaging. Drying altered the amount of moisture between the fruit interior and surface. Vitamin A1 is lipophilic and localized at the desiccated outer regions (pericarp) and not in the inner region (mesocarp and endocarp), and its concentration was increased 3.4 times in dried fruit compared with raw persimmon. Vitamin B1 and B6 are water-soluble and concentrated in the moist mesocarp. The vitamin C content of dried persimmon is decreased by drying in the sun. The drying process affected the localizations and amounts of all the vitamins. The observed opposite localization of vitamin A1 compared to B1 and B6 was due to vitamin A1 being lipophilic and B1 and B6 being water soluble. Multiplevitamin imaging using MALDI-MSI has great potential for enhancing commodity value and for visually investigating the effects of manufacturing processes.