Determination of flavor components of rice bran by GC-MS and chemometrics

The flavor composition of rice bran was investigated using solid-phase microextraction (SPME), which was selected from four extraction methods. Additionally, static headspace extraction (SHS), accelerated solvent extraction (ASE) and simultaneous distillation extraction (SDE), followed by GCMS analysis with the help of heuristic evolving latent projections (HELP) were also used. The effects of the most important factors, including fiber coating, extraction time, and temperature of SPME, on the flavor components of rice bran were studied. Qualitative analysis of the flavor components was obtained by a mass spectra similarity search using pure mass spectra resolved by HELP with the aid of automated mass spectral deconvolution and identification system (AMDIS) software and temperatureprogrammed retention indices (PTRIs), while quantitative analysis was conducted using the overall volume integration (OVI) technique. A total of 43 out of 76 compounds were tentatively identified, accounting for 82.76% of the total flavor compounds. The flavor compounds were mainly esters, alkanes, alcohols, ketones, aldehydes, and fatty acids, with a composition of 22.24%, 22.16%, 17.75%, 9.06%, 5.72%, and 4.18%, respectively. Together, these results indicate that analyzing the rice bran flavor profile may be more reasonable than solely monitoring free fatty acids for understanding, evaluating and controlling the instability of rice bran.