High-pressure liquid chromatography of apple juice phenolic compounds

Apple juice phenolic compounds: (+)‐catechin, (‐)‐epicatechin, chlorogenic acid, phloridzin, phloretin xyloglucoside, and the polymeric procyanidins from the dimeric to the heptameric, were separated by high‐pressure liquid chromatography on a CN column, run in the normal phase, using an acidified tetrahydrofuran‐hexane solvent gradient. Individual procyanidin fractions, of different degrees of polymerisation, were collected from the CN column and the isomers from each fraction were then separated on a C18 column, using a methanol‐aqueous KH2PO4 solvent gradient.