The influence of different air-drying conditions on bioactive compounds and antioxidant activity of berries

Abstract

Abstract: The aim of the present research was to study the effect of convective drying on color, bioactive compounds and antioxidant activity of berry fruits and to chemically characterize the polyphenolic composition of raspberry, boysenberry, redcurrants and blackcurrants fruit. Drying berries at 65 ºC provoked the best conservations of color, particularly for boysenberry and blackcurrant. Drying at 65 °C was also the condition that showed higher level of polyphenols, while drying at 50 ºC or 130 ºC showed above % degradation of them due to the long time or high temperature drying. Radical scavenging activity was the predominant antioxidant mechanism in all samples, being 65 °C dried berries the most active ones possibly due to polyphenols depolymerization. The anthocyanin profile showed that delphinidin and cyanidin derivatives were the most abundant anthocyanidins with different predominance between berry genera. Degradation of anthocyanins was increased with drying temperature been Cy 3-glucosde and Cy 3-rutinoside the most abundant.