Polyphenolic Content and Antioxidant Capacity in Fruits of Plum (Prunus domestica L.) Cultivars “Valjevka” and “Mildora” as Influenced by Air Drying

Abstract

Polyphenolic content and antioxidant capacity of freshly harvested plums cvs. “Valjevka” and “Mildora,” and changes caused by drying were analyzed. Plum drying at 90C resulted in significant changes in anthocyanins, flavonoids and phenolics content, and antioxidant capacity in both cultivars examined. Statistical analysis showed that antioxidant capacity of both fresh plums and prunes of “Valjevka” and “Mildora” is strongly influenced by the phenolic constituents of the fruit. The major phenolic compound in fresh plums and prunes is neochlorogenic acid, followed by caffeic acid and chlorogenic acid. After drying, a significant decrease in neochlorogenic acid and an increase in caffeic acid was observed, while chlorogenic acid content decreased in prunes of “Valjevka,” and increased in prunes of “Mildora.” Rutin and protocatechuic acid contents were slightly decreased after drying, while gallic acid content was dramatically increased. A complete degradation of cyanidin was induced by drying.