Effect of hot air drying temperatures on drying characteristics and physicochemical properties of beetroot (Beta vulgaris) slices

The objective of this study was to investigate the influence of hot air drying temperatures ranging from 50 to 100 degrees C on the drying characteristics and physicochemical properties of beetroot slices. The results showed that by increasing temperatures from 50 to 100 degrees C, the drying time could be from 12.5 to 4.5 h, which could significantly increased the drying rate. The beetroot slices dried at 60 degrees C showed the smallest total color difference compared with fresh beetroot slices. The betalain content (betacyanin and betaxanthin) of beetroot slices decreased with the increase of drying temperatures, and betacyanin was more temperature sensitive than betaxanthin. The total phenol content and antioxidant capacity had the same trend with drying temperatures, and both reached to the maximum at 100 degrees C.