Effect of sequential-combined solar energy assisted hot air and hot air assisted radio frequency drying on the physical and chemical properties of dried apricots

Quality characteristics of sulphured and non-sulphured apricots dried with a sequential combined pilot scale solar assisted hot air and hot air assisted radio frequency dryer and conventional sun system were compared. The combined drying approach showed improved color, hardness, antioxidant activity and retention of vitamin C, beta-carotene and total phenolic content values compared to conventional sun drying both for sulphured and non-sulphured samples. The effects of sulphur concentration and addition of pistachio hull extract as a treatment prior to drying were also investigated. Increase in sulphur concentration and addition of extract resulted in considerable quality (with respect to color, Vitamin C, beta-carotene and total phenolic content) increase in apricots. The apricots pretreated with extract had the highest total phenolic content and antioxidant activity. This study demonstrated that combined drying process is an effective drying method for apricots with the better preservation of product quality attributes.