Sour cherry (Prunus cerasus L.) is a very important fruit crop for producers as well as consumers. To obtain information on sour cherry fruit, we determined the sugar and organic acid composition and phenolic compound contents of twenty-one cultivars and genotypes of Prunus cerasus L. by HPLC quantification. Antioxidant capacity was determined by DPPH radical scavenging, reducing power (FRAP) and determination of substances reacting with Folin-Ciocalteu reagent (FCRS). The main organic acids in sour cherries were malic and malonic acids, and the main sugars were glucose and fructose. The highest sugar content was found in the "Lucyna" cultivar and the highest organic acids in "Paraszt Meggy" and "Suda Hardy". The richest in phenolic compounds were "Wieluń 17", "Sokówka Nowotomyska", "Grosenkirch" "Sokówka Nowotomyska" "Grosenkirch" (anthocyanins, flavanols and total phenolics), and "Meteor" (phenolic acids). Flavan 3-ols were not quantified in every cultivar. "Dradem, "Turgieniewka", "Wróble", and "Nana" contained the smallest amounts of phenolic compounds. Antioxidant capacity was highly correlated with phenolic compound composition. According to principal component analysis (PCA), it was concluded that cultivars whose harvest maturity was medium to late contained more flavonols and anthocyanins and were characterized by higher antioxidant capacity than those whose harvest maturity was classified as early or early to medium.
Keywords: antioxidant capacity; organic acids; phenolic compounds; sour cherry; sugars.