Effects of sun-drying on physicochemical characteristics, phenolic composition and in vitro antioxidant activity of dark fig varieties

The aim of this investigation was to study the effects of sun-drying on some physicochemical parameters, phenolic profiles, and antioxidant activities of three dark fig varieties. Sun-drying led to a decrease of weight and moisture content, an increase of sugar content, but not affect acidity. HPLC analysis revealed the presence of 22 phenolic compounds (14 phenolic acids and 8 flavonoids), including eight compounds that were detected for the first time. Phenolic acid contents decreased after sun-drying by about 29%, except cinnamic and gallic acids that were increased. Fresh dark fig contained high levels of flavonoids, particularly cyanidin 3-rutinoside and quercetin 3-rutinoside; sun-drying caused decrease in flavonoid contents by about 86%. There are a lot of antioxidant bioactive components besides the phenolic compounds as studied in this work; therefore, the reduction of phenolic compound content by sun-drying could mainly contribute to the reduction of antioxidant activity of the dark figs.

Practical applications

This work aimed to study the effect of sun-drying, a widely used method for fig drying, on the physicochemical properties, phenolic profiles and antioxidant activities of three dark figs varieties. The sun-drying method allows the elaboration of dark dried figs with required moisture, but causes a significant reduction of bioactive compounds content as well as antioxidant activity. Safety measures are needed to reduce this negative effect.