Abstract: Objective: To determine the contents of nutrients and heavy metals in germinated brown rice bran (GBRB) and establish a high performance liquid chromatography (HPLC) method to detect gamma-aminobutyric acid (GABA) in GBRB, as well as to evaluate the anti-fatigue activity of GBRB. Methods: The content of GABA was determined by HPLC with pre-column o-phthalaldehyde derivatization. Fifty male SD rats were randomly divided into five groups: control, high-fat diet and low-dose (10%), medium-dose (20%), high-dose (30%) GBRB groups. After feeding for 83 days, the rats were forced to swim until exhausted, and the weight-loaded swimming time was recorded. Results: The crude fiber and ash contents in GBRB were nearly 29% of those in ungerminated brown rice bran, although both had similar contents of crude protein, total amino acids and individual amino acids (except for cystine). In addition, the contents of all investigated inorganic elements were lower in GBRB, and the contents of all heavy metals were below the safe limits set in the national standard (GB 2762?2012). Our HPLC method presented good linearity over the concentration range of 68.7–275.0 μg/mL with correlation coefficient (R2) of 0.999 9. The GABA content in GBRB was determined to be 53 mg/100 g. The average recovery of this method was 99.61%. Compared with the control group, high-dose GBRB significantly prolonged the exhaustive swimming time (P < 0.05). Conclusion: The contents of nutrients in brown rice bran change and the GABA content increases after germination. High-dose consumption of GBRB helps prolong the exhaustive swimming time of rats, indicating the anti-fatigue activity of GBRB.

Key words: germinated brown rice bran, nutritional composition, gamma-aminobutyric acid, high performance liquid chromatography, anti-fatigue