Antioxidant activity, flavonols and phenolic acids of various fruits

Total polyphenols (TP), total anthocyanins (TA) and antioxidant activity of various fruits (black currant, red currant, sour cherry, elderberry, and blueberry) were determined by using Folin-Ciocalteau, pH-differential and DPPH method. In order to identify individual non-anthocyanic phenolic compounds [flavonols (quercetin, myricetin, kaempferol), phenolic acids (p-coumaric, caffeic, ferulic, p-hydroxybenzoic and ellagic acid)] present in chosen fruits, HPLC method was applied. The highest amounts of TP and TA, and the strongest antioxidant activities were found in blueberry, elderberry and black currant. The major non-anthocyanic phenolic component in elderberry and blueberry was quercetin. In black currant, myricetin was the most abundant phenolic compound. P-hydroxybenzoic acid was the main phenolic compound of red currant, whereas p-coumaric and caffeic acid were the most abundant phenolic compounds of sour cherry.