Aim of the present study was to evaluate the effect of different drying techniques on chemical composition, color and antioxidant activity of kinnow peel. Fresh peel was dehydrated by three different techniques (tray, vacuum and freeze) and regardless of the method results showed significant decreases in moisture, total phenols, flavonoids, antioxidant activity and color when compared to the fresh sample. Freeze drying was found superior in retention of polyphenolic characteristics and color attributes when compared with other drying techniques. The fresh and freeze-dried citrus peel extract was analyzed for individual phenolics and flavonoids with the help of HPLC indicating highest concentrations of ferulic acid and hesperidin.
Keywords: Drying techniques; Freeze-drying; Kinnow peel; Phytochemicals analysis.