Abstract: The present study was carried out to determine total microbial count andγ-aminobutyric acid (GABA) content on the surface, respiration intensity and reducing sugar content during the germination of brown rice from late Indica rice cultivar Ganxian 923 in the presence of either tea tree oil alone, organic acids such as ascorbic acid, citric acid and calcium lactate together, all of them or none of them. The results indicated that 4.0 g/L ascorbic acid/2.0 g/L citric acid/3.0 g/L calcium lactate solution could enhance respiratory intensity, promote the accumulation of GABA and accelerate the degradation of starch to reducing sugars. On the contrary, tea tree oil (4.5 g/L) had obvious inhibitory effect on respiration intensity, starch degradation and GABA accumulation. Moreover, tea tree oil and organic acid solution revealed a synergistic effect on the inhibition of bacterial growth in germinating brown rice.

Key words: germination, tea tree oil, organic acid, brown rice