The impact of Rhizopus oryzae cultivation on rice bran: Gamma-oryzanol recovery and its antioxidant properties

•First report solid state cultivation with Rhizopus oryzae on recovery of γ-oryzanol.•The γ-oryzanol recovery increased by 51.5% in 48 h cultivation.•Gamma-oryzanol obtained from 96 h fungal biomass inhibited in 90.5% the oxidation.•Cultivation process provided improvements of the functional properties of rice bran.

This study evaluated the effect of the solid state cultivation (SSC) time of rice bran by Rhizopus oryzae on γ-oryzanol recovery and its antioxidant properties. Gamma-oryzanol was extracted with organic solvents and its extracts were characterized by GC-FID and HPLC-UV. The antioxidant capacity was assessed by DPPH and ABTS+ assays, β-carotene/linoleic acid system, and reduction of oxidation in lipid system. The biomass showed the γ-oryzanol recovery increased by 51.5% (20.52 mg/g), and 5.7% in polyunsaturated fatty acids. The γ-oryzanol major components changing in their profile. The γ-oryzanol extract from biomass (72 h) showed the greatest DPPH inhibition (59.0%), while 90.5% inhibition of oxidation of β-carotene/linoleic acid system, and 30% reduction of the indicators of oxidation in olive oil was observed in the one cultivated at 96 h, these behaviors were confirmed by PCA analyses. SSC provides an increase in the γ-oryzanol recovery followed by improving of the functional properties of rice bran.