The effect of anaerobic treatment on polyphenols, antioxidant properties, tocols and free amino acids in white, red, and black germinated rice (Oryza sativa L.)

• This study is the first to report on the effects of anaerobic treatment on the antioxidant properties of GBR.
• Anaerobic treatment improved the TPC, TFC and antioxidant activity.
• The most pronounced increase in phenolic acids was the ferulic, coumaric, and sinapic acids.
• γ-Aminobutyric acid (GABA) and some amino acids were increased significantly.
• Anaerobic treatment had no effect on the content of the tocols.

The effects of anaerobic treatment on the content of polyphenols, antioxidant capability, tocols, and free amino acids (FAAs) in the germinated brown rice (GBR) were investigated. The values of polyphenols and antioxidant capability significantly increased in treated groups, in which the three phenolic acids, i.e. ferulic, p-coumaric, and sinapic acids, showed the most pronounced increase. No significant change was observed in tocols. Among the evaluated FAAs, only the content of aspartic and glutamic acids in the white, red and black GBRs decreased by 75, 65 and 69%, and by 30, 18 and 39% after anaerobic treatment, respectively. While the contents of serine and threonine remained unchanged, all others significantly increased. In particular, the contents of γ-aminobutyric acid (GABA) increased 4.2-, 9.7- and 4.8-folds in the white, red and black GBRs, respectively. The results indicated that additional anaerobic treatment could be used in the production of GBR as a functional food.