Effect of inulin concentration on physicochemical properties and antioxidant activity of date powders obtained by hot-air tray dryer

Abstract

In the present study, it was aimed to produce free-flowing date powders using various levels of inulin as dryingaid agent (10, 20, 30, 40, and 50%) through hot-air drying at 60°C for 24 h. Effects of different inulin ratios on physicochemical properties of date powders were investigated. This is the first report which evaluated the suitability of this prebiotic carbohydrate as drying-aid agent to fabricate date powders. Inulin addition yielded date powders with high flowability. On the other hand, contents of bioactive compounds including total phenolics, flavonoids, and condensed tannins of date powders decreased significantly (P<0.05) as the inulin concentration increased from 10% to 50% Accordingly, DPPH-radical inhibition capacities reduced in date powders containing higher levels of inulin. Furthermore, significant correlations were detected between bioactives contents and antioxidant activity of date samples. The results showed that free-flowing date powders with improved prebiotic content may be produced by incorporating inulin up to ratio of 50% and used as sugar substitute in different food products.