Changes in phenolic composition of apple juices by HPLC with direct injection

An analytical procedure for the quantitative determination of the major pol yphenols in apple juices which successfully employs a RP-HPLC system withou t prior treatment of the sample is described. Apple juices were clarified b y microfiltration and ultrafiltration without previous treatment. Polypheno ls monitored were influenced by clarification technology employed for stabi lising the apple juices. The p-coumaric acid derivative was significantly a ffected by membrane type and filtration time, while (-)-epicatechin and phl oridzin were influenced by filtration time. (C) 1998 Society of Chemical In dustry.