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The cuticle wax of the grape is was found to be composed of a soft wax(30%) readily removed by light petroleum and a hard wax (30%), mainly oleanolic acid, removed by chloroform. The soft wax of the fresh grape is composed chiefly of long-chain alcohols together with smaller amounts of aldehydes, esters, fatty acids, hydrocarbons, oleanolic acid, and small amounts of high molecular weight substances. The soft wax of dried grapes is similar in composition but contains no aldehydes and larger amounts of high molecular weight substances and oxidation products.

The Composition of Grape Cuticle Wax

1964, Australian Journal of Chemistry, vol 18, pages 1059 – 1069

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