Abstract:

A simple and fast high performance chromatography (HPLC) with UV detection method for determination of
γ-amino butyric acid (GABA) in germinated brown rice was developed by pre-column derivatization of GABA with orthophthalaldehyde
(OPA). GABA was separated on intertsil ODS-C18 column (4.6 mm × 250 mm, 5 μm) and detected with UV
detector at 332 nm. Good linearity was observed within the range from 0.005 to 0.06 mg/mL from the calibration equation:
Y = 9.26 × 106X + 2 093.79 (r = 0.999 5), and the limit of detection was 2.927 ng. The relative standard deviation (RSD)
of peak area was 0.57%, and the recoveries were 98.85%–100.94% for GABA. The method is easy to operate, time-saving
and highly precise. GABA contents in 20 cultivars of germinated brown rice were 22.68–88.36 mg/100 g on a dry weight
basis as determined by the method. The result showed that GABA content in germinated brown rice varied with cultivar and
Zhongiazao 17 and Zhefu 802 contained significantly more GABA than the other cultivars tested (P ＜ 0.05). Thus, attempt
can be made to use germinated brown rice products from the two cultivars as raw materials in practical production

Key words: germinated brown rice, γ-aminobutyric acid, ortho-phthalaldehyde, high performance chromatography (HPLC)