Morphological Structure and Chemical Composition in Epicuticular Wax of Fruits in Four Kinds of Grape Cultivars

Abstract

The epicuticular wax appears to cover the skin of grapes as white powder, so it's often misunderstood as agricultural chemicals, yeast, or sugar. In order to find the components of this kind of fruit powder, a qualitative analysis was conducted through GC-MS (Gas Chromatography Mass Spectrometry) on 'Campbell Early', 'Kyoho', 'Hongisul', and 'Cheongsoo'. As the results, the aliphatic compounds of alkalies, primary alcohols, aldehydes, esters, and fatty acid were detected from all four species. It was also found that the main components of red grape species were alkanes and ester, whereas the main component of white grape species was alkanes. In addition, the inspection result for the quantity of epicuticular wax in each species showed that the highest was 'Cheongsoo' (943.07 mu g . cm(-2)), followed by 'Campbell Early' (636.78 mu g . cm(-2)), 'Hongisul' (605.30 mu g . cm(-2)), and 'Kyoho' (147.62 mu g . cm(-2)). In order to examine the ultrastructure Of fruit epicuticular wax, the grape berries of the harvesting seasons was observed through a scanning electron microscope, and it was found that all four species of grapes, 'Campbell Early', 'Kyoho', 'Hongisul', and 'Cheongsoo', had platelets with no regular direction, and in particular, 'Kyoho' and 'Cheongsoo' were examined to have both basic and long line-shaped platelets.