Comparison of the phenolic composition of fruit juices by single step gradient HPLC analysis of multiple components versus multiple chromatographic runs optimised for individual families

After minimal sample preparation, two different HPLC methodologies, one bas ed on a single gradient reversed-phase HPLC step, the other on multiple HPL C runs each optimised for specific components, were used to investigate the composition of flavonoids and phenolic acids in apple and tomato juices. T he principal components in apple juice were identified as chlorogenic acid, phloridzin, caffeic acid and p-coumaric acid. Tomato juice was found to co ntain chlorogenic acid, caffeic acid, p-coumaric acid, naringenin and rutin . The quantitative estimates of the levels of these compounds, obtained wit h the two HPLC procedures, were very similar, demonstrating that either met hod can be used to analyse accurately the phenolic components of apple and tomato juices. Chlorogenic acid in tomato juice was the only component not fully resolved in the single run study and the multiple run analysis prior to enzyme treatment. The single run system of analysis is recommended for t he initial investigation of plant phenolics and the multiple run approach f or analyses where chromatographic resolution requires improvement.