###### Abstract  
In the present study, germinated brown rice (GBR) from three _Japonica_ and three _India rice_ cultivars were subjected to metabolomics analysis and volatile profiling. The statistical assessment and pathway analysis of the metabolomics data demonstrated that in spite of significant metabolic changes in response to the germination treatment, the _Japonica rice_ cultivars consistently expressed higher levels of several health-promoting compounds, such as essential amino acids and \(\gamma\)-aminobutyric acid (GABA), than the _India_ cultivars. No clear discriminations of the volatile profiles were observed in light of the subspecies, and the concentrations of the volatile organic compounds (VOCs), including alkenes, aldehydes, furans, ketones, and alcohols, all exhibited significant reductions ranging from 26.8% to 64.1% after the germination. The results suggest that the _Japonica_ cultivars might be desirable as the raw materials for generating and selecting GBR food products for health-conscious consumers.  
brown rice; metabolomics; volatile; GC-MS; HS-SPME 2021 2 October 2021 12 October 2021 14 October 20  
rice (GBR) at different germination stages. [PERSON] et al. [8] revealed the remarkable rise in the amounts of tocopherols, tocotinols, and \(\gamma\)-oryzanol in GBR after gemination treatment.  
Compared with the above-mentioned targeted analyses of constituents, metabolomics nowadays has been applied to reveal a more comprehensive metabolite mapping of cereal grains. For example, non-targeted metabolite profiling was employed to reveal the metabolic changes after seed germination of the _India_ cultivar DHX [9]. [PERSON] et al. [10] compared the metabolic differences of four Thai colored _India_ GRB with the use of the metabolite profiling approach. Currently, a limited amount of information is available only for _India_ GBR regarding the global metabolic characterization, while no metabolomics-based investigation of _Japonic_ GBR has ever been reported.  
Rice cultivars are mainly grouped into _Japonica_ subspecies and _India_ subspecies based on the geographical distribution, plant architecture, and physiological features [11]. Usually, _Japonica rice_ grains are short, roundish, and sticky, and are often consumed in North China. By contrast, _India rice_ kernels are slender and more popular in South China. Accordingly, the overall metabolite profiles of the GBR generated from these two subspecies are expected be to distinct. However, limited information is available regarding the metabolic differentiation between the _Japonica_ GBR and the _India_ GBR. Additionally, it also remains unclear whether the volatile profiles of the _Japonica_ GBR and the _India_ GBR are different.  
In the present study, a gas chromatography-mass spectrometry (GC-MS)-based metabolomics approach was employed to comprehensively characterize the metabolite profiles of GBR from three _India_ and three _Japonica rice_ cultivars. In addition, the head-space solid-phase microextraction GC-MS (HS-SPME-GC-MS) method combined with chemometric analysis were utilized to explore the volatile profiles of the GBR resulting from the _Japonica_ and the _India_ subspecies. The objectives of this study were: (i) to investigate the changes in metabolite profiles and volatiles in rice seeds upon germination treatment, and (ii) to compare the global metabolic and volatile differences between the _Japonica_ and the _India_ GBR. The elaborated data are expected to increase the knowledge in generating and selecting GBR food products for health-conscious consumers.