The use of organic sun-dried fruits for delivery of phenolic compounds

Abstract

The aim of this study is to characterize and increase the total soluble (water soluble + alcohol soluble) phenolic (SPCT) and flavonoid content (SFCT) and total soluble free radical scavenging based antioxidant capacity (SACT) of major sun-dried fruits such as raisins, figs, prunes and apricots. Due to their high insoluble dietary fiber content, the bound antioxidant capacity formed 61 to 67% of the overall antioxidant capacity (water soluble + alcohol soluble + bound) of sun-dried fruits. The SPCT, SFCT and SACT of sun-dried fruits changed between 1675 and 3860 μg catechin/g (d.w.), 161 and 495 μg catechin/g (d.w.) and 13 and 28.5 μmol Trolox/kg (d.w.), respectively. The incorporation of green tea polyphenols into sun-dried raisins, figs and apricots by controlled rehydration conducted in green tea extracts increased their SPCT, SFCT and SACT 1.5 to 1.8 fold, 1.3 to 1.6 fold, and 1.5 to 2.6 fold, respectively. The method applied caused limited increases in SPCT (1.1 fold) and SFCT (1.2 fold) of prunes, but it increased SACT of these fruits 1.6 fold. This study showed the possibility of using sun-dried fruits not only as source of dietary fiber, but also for delivery of phenolic compounds. The methods used in this study for delivery of green tea phenolic compounds to selected organic sun-dried fruits could be an alternative method to increase intake of these invaluable antioxidant compounds and increase functionality of sun-dried fruits which are already accepted as good source of dietary fiber.