Composition of the surface waxes of apple fruits and changes during storage

Abstract The hydrolysed surface waxes of Dougherty, Granny Smith and Sturmer apples at harvesting consisted of 57 to 62% acids, 21 to 26% hydrocarbons, 7% primary alcohols, 3 to 5% secondary alcohols and 4 to 7% of other constituents. The hydrocarbon homologues ranged from C18 to C31 with n‐nonacosane comprising 84 to 92% of the total hydrocarbons. The primary alcohols (C14 to C28) were mainly n‐hexacosanol in Sturmer and n‐tetracosanol in Dougherty and Granny Smith cultivars, the amounts of these alcohols being, respectively, 53.4, 32.4 and 35.6% of the total alcohols. In all three cultivars the secondary alcohols consisted almost entirely of one component, possibly nonacosan‐10‐ol. The Sturmer waxes were distinguished from those of the Dougherty and Granny Smith by a lower content of linoleic and by a generally higher content of palmitic acid. During storage the amount and composition of the waxes of Sturmers did not change appreciably. The wax content of the Granny Smith cultivar increased up to 268 days and that of the Dougherty up to 70 days of storage. Changes in fatty acid composition also occurred during storage, the most remarkable being the up to 11‐fold elevation of the linolenic acid content of the Granny Smith apples.