Polyphenol profiles of French cider apple varieties (Malus domestica sp.)

The cortex of 14 French apple varieties (12 cider and 2 juice varieties), o ne English cider variety, and one dessert apple (i.e., Golden Delicious) we re studied for their polyphenol composition. Total polyphenols were assayed by the Folin-Ciocalteu method, and the precise polyphenolic composition (m onomeric catechins, proanthocyanidins, hydroxycinnamic acids, and dihydroch alcones) was obtained by HPLC following thiolysis. ESI-MS and ESI-MS/MS ana lyses showed that chlorogenic acid and p-coumaroylquinic acid were methylat ed under the conditions of thiolysis. Depending on the variety, the global polyphenol concentration varied from 1 to 7 g per kilogram of fresh cortex. Cider varieties globally showed a higher polyphenol concentration than the dessert apple Golden Delicious, bitter varieties being the more concentrat ed. The proportion of the polyphenol classes varied greatly from one cultiv ar to another. For all varieties, procyanidins were always the predominant class. They were mainly constituted of (-)-epicatechin units with a small p roportion of(+)-catechin as a terminal unit. The average degree of polymeri zation ranged between 4.2 and 7.5 depending upon the variety with an except ion for the sharp varieties Guillevic and Avrolles which showed significant concentrations of procyanidins with DPn of 40 and 50, respectively.