Abstract: The present study aimed to investigate the effects of different drying methods including sun drying, vacuum freeze drying, oven drying, far-infrared drying and vacuum drying on the total polyphenol content, polyphenol composition and antioxidant activities in vitro of figs. The contents of total and individual polyphenol compounds were determined by the Folin-Ciocalteu method and high performance liquid chromatography (HPLC), respectively. In addition, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, 2,2’-azino-bis-(3-ehtylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging capacity and reducing power of polyphenols extracted from dried figs were determined and correlated with polyphenol contents. The results showed that the contents of both total and individual polyphenol compounds were significantly affected by the drying methods (P < 0.05) and both the total polyphenol content and the summation of individual polyphenol compounds in vacuum dried figs were the highest. The antioxidant activities of polyphenols extracted from figs were also significantly affected by the drying methods (P < 0.05). Vacuum drying resulted in higher DPPH radical and ABTS+· scavenging capacity and reducing power of polyphenols from dried figs than other drying methods. The antioxidant activity of figs presented a significant correlation with polyphenols including catechin, quercitrin, ferulic acid, and 4-hydroxybenzoic acid (P < 0.05). Based on these results, vacuum drying is the most suitable method for preserving polyphenol compounds and antioxidant activity in figs.

Key words: fig, drying methods, polyphenol, antioxidant activities, correlation analysis