Analysis of phenolic compounds in six Norwegian plum cultivars (Prunus domestica L.).

Six European plum cultivars ( Prunus domestica L.) grown in Norway have been studied with respect to phenolic composition. Neochlorogenic acid was found to be the most important phenolic acid in all cultivars. Together with other phenolic acids, this compound varied significantly in amount among the cultivars. Cyanidin 3-rutinoside was found to account for >60% of the total anthocyanin content. Minor amounts of flavonols (rutin and quercetin 3-glucoside) were detected in all cultivars. Total antioxidant capacity varied from 814 to 290 micromol of Trolox 100 g(-1) of fresh weight. Measurement of total phenolic content in terms of Prussian blue complex formation revealed a method failure of magnitude order compared to results obtained by HPLC. Comparison of the response factors of a range of phenolic compounds obtained upon analysis by the Prussian blue and Folin-Ciocalteu assays revealed that the latter method returned higher yields in terms of gallic acid (GAE).