Effect of superfine-grinding on the physicochemical and antioxidant properties of Lycium ruthenicum Murray powders

Dried Lycium ruthenicum Murray (LM) fruits were ground by three different methods. The results showed that LM powders produced by superfine-grinding had smaller particle size (1.78–200.00 μm) as compared to shear-breaking and ball-milling. As a consequence, its bulk density, angle of repose and angle of slide were increased to 0.71 g/mL, 52.99° and 60.38°, respectively. Moreover, the superfine-ground LM powders displayed good dispersibility and infusion properties, showing improved water holding capacity and water solubility index than other powders during infusion. Consequently, the phytochemicals present in the superfine-ground LM powders could be released more easily, leading to the powders with higher anthocyanin and polysaccharide contents (24.50 and 160.54 mg/g) and antioxidant activities (DPPH, ABTS and FRAP: 34.53, 42.19 and 40.25 mM TE/g, respectively) than other powders. The results suggested that superfine-grinding could be a promising method for producing LM powders with higher contents of bioactive compounds and bioactivity.