TY - JOUR T1 - The main Constituents of the Surface Waxes of Varieties and Species of the Genus <em>VITIS</em> JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. SP - 159 LP - 167 DO - 10.5344/ajev.1965.16.3.159 VL - 16 IS - 3 AU - F. Radler Y1 - 1965/01/01 UR - http://www.ajevonline.org/content/16/3/159.abstract N2 - Cuticular waxes from fresh grapes and leaves of Vitis vinifera, Vitis labrusca, Vitis rupestris, several Vitis hybrids, and Parthenocissus quinquefolia were extracted with cold chloroform. The main constituent of the waxes from grapes was oleanolic acid, which is present in the surface wax of leaves in only small amounts. The chloroform extracts were separated by extraction with petroleum ether into the insoluble "hard wax", consisting mainly of oleanolic acid, and the soluble "soft wax," which was fractionated by chromatography on aluminum oxide into hydrocarbons, an "ester-aldehyde" fraction, free alcohols, and free acids. The waxes of all grape vine varieties appeared to have a similar composition except V. labrusca var Isabella, which contained a much higher amount of hydrocarbons in the cuticular wax. The compositions of the hydrocarbons, free alcohols, and free acids were determined by gas-liquid chromatography. The following chain-length distributions were found: hydrocarbons, n-C18 to n-C35, with n-C25, n-C27, n-C29 and n-C31 as main constituents; alcohols, n-C20 to n-C34, with n-C26 in grapes and n-C28 and n-C30 in leaves as main constituents; acids, n-C14 to n-C32, with n-C26 as the main constituent. Except for the high content of paraffins in V. labrusca, the differences between the analyzed varieties and species of grape vines were small. ER -