Effects of different drying methods on phenolic content, antioxidant capacity and general characteristics of selected dark colored Turkish fig cultivars

Abstract

ig fruit is a good source of minerals and crude fibers. The dark-colored fig cultivars rich in anthocyanins are also known with their high polyphenol content. However, although there are many different dark-colored fig cultivars grown in Turkey, the dried fig industry has traditionally been concentrated on drying of several yellow-colored fig cultivars. The aim of this study is to determine the effects of sundrying and oven-drying on some general characteristics, phenolic content and antioxidant capacity of 2 dark-colored (black) and 2 light-colored (yellow) fig cultivars selected from genetic collection of Turkish Fig Research Institute. The figs were obtained by harvesting at the semi-dry stage at 40-50% moisture content and applying sun-drying or oven-drying to reach final moisture content between 20 and 26%. The sun-drying was conducted on mats for 2-3 days under the sun while the oven-drying was applied for 12 h at 60°C and at the air velocity of 0,5 m s-1. The result of the study clearly showed almost 1,5-2 fold higher total phenolic content and ABTS free radical scavenging based antioxidant capacity of fresh dark-colored figs than fresh light-colored ones. The drying had almost no negative effects on the total phenolic content of both dark- and light-colored figs. The drying also did not have a negative effect on antioxidant capacity of light-colored figs, but it caused a limited reduction (between 20 and 30%) in antioxidant capacity of dark-colored figs due to the well-known heat labile nature of their color compounds anthocyanins. The use of sun-drying or oven-drying did not have a considerably different effect on final phenolic contents and antioxidant capacities of dried figs. This study clearly showed that it is possible to obtain phenolic rich dried figs by use of dark colored fig cultivars such as TR1101 and TR1102.