High-Performance Liquid Chromatography of the Neutral Phenolic Compounds of Low Molecular Weight in Apple Juice

Abstract

The neutral phenolic compounds, (+)-catechin, (-)-epicatechin, flavan-3-ols polymers (procyanidins), phloridzin, phloretin xyloglucoside, and the flavonol glycosides (isoquercitrin, hyperin, quercitrin, avicularin, and rutin), in apple juice were extracted with ethyl acetate and separated and quantified by reversed-phase HPLC on a C18 column using an acidified water (pH 2.8)-methanol solvent gradient. A diode array detector was used to evaluate the separation and to identify the phenolic compounds. The recovery obtained for the flavanols and some dihydrochalcones ranged between 93% and 106%. On the contrary, the 30% recovery rate obtained for flavonols shows that ethyl acetate liquid-liquid extraction, usually employed in this type of study, is not recommended for the extraction of these last compounds.