The application and mechanism of action of Michelia alba oil vapour in GABA enhancement and microbial growth control of germinated brown rice

Abstract Germination of brown rice as a functional ingredient in various food products has been found to increase the γ-aminobutyric acid (GABA). Due to its high nutritional impact, germinated brown rice (GBR) grains are easily contaminated with bacteria, yeast/mould. Bacillus cereus is a foodborne pathogen and spoilage bacteria commonly found in GBR. This study was undertaken to use Michelia alba oil vapour (600, 1200 and 2400 μl L−1) to increase GABA during germination of brown rice grains over 48 h. The shelf life of the treated GBR was then determined during storage at 30 ± 2 °C for 28 days by finding physiochemical and physical changes in the treated rice and undertaking sensory evaluation. A mode of action was studied by using a scanning electron microscope (SEM) and gas chromatography-mass spectrometry (GC-MS). Results showed that the treated brown rice grains at 1200 μl L−1 before the germination process showed the highest GABA content in the shortest time at 18 h, reducing cooking time and having a softer texture compared to the control sample. The treated rice's aerobic plate count, yeast/mould count and B. cereus levels were better able to meet the microbiological criteria for rice and rice products (