Aspergillus oryzae Fermented Rice Bran: A Byproduct with Enhanced Bioactive Compounds and Antioxidant Potential.

Area of Science:

• Biotechnology
• Food Science
• Agricultural Byproducts

Background:

• Rice bran (RB) is a readily available byproduct of rice milling.
• Valorization of RB is crucial for sustainable agricultural practices.
• Fermentation offers a method to enhance the nutritional and functional properties of RB.

Purpose of the Study:

• To investigate the impact of fermentation duration on the antioxidant properties of rice bran.
• To optimize the fermentation process for increased antioxidant potential.
• To quantify changes in key bioactive compounds during fermentation.

Main Methods:

• Solid-state fermentation (SSF) of RB using Aspergillus oryzae MTCC 3107.
• Determination of Total Phenolic Content (TPC) via Folin-Ciocalteu assay.
• Assessment of antioxidant activity using DPPH, TAC, ABTS+, RPA, and HFRSA assays.
• Quantification of specific bioactive compounds (gallic acid, ascorbic acid) using High-Performance Liquid Chromatography (HPLC).

Main Results:

• TPC increased significantly until the 4th day of fermentation.
• Antioxidant activities (TAC, DPPH, ABTS+, RPA) peaked on the 4th day and then declined.
• HPLC analysis revealed a significant increase in gallic acid (23.3 µg/g) and ascorbic acid (12.7 µg/g) on day 4.
• Fermented rice bran (FRB) demonstrated superior antioxidant potential compared to unfermented rice bran (URB).

Conclusions:

• Solid-state fermentation (SSF) effectively enhances the antioxidant potential and TPC of rice bran.
• Optimal fermentation duration for maximizing antioxidant properties was found to be 4 days.
• Fermentation with Aspergillus oryzae is a viable strategy for valorizing rice bran into a functional food ingredient.