Using liquid chromatography-mass spectrometry based metabolomics to discriminate between cold pressed rice bran oils produced from two different cultivars of Oryza sativa L. ssp. indica in Thailand

A newly developed liquid chromatography-mass spectrometry (LC-MS) method for the analysis of cold pressed rice bran oil (RBO) was established and used to discriminate between RBOs produced from two different cultivars of major Thai fragrant rice species. The cold pressed RBO was prepared using the screw compression method. The LC-MS data were preprocessed with MZmine 2.10 program before evaluating with principal component analysis using SIMCA 13 software. The LC-MS method was able to detect and quantify several kinds of valuable constituents such as fatty acids, vitamin E, and γ-oryzanol. The chromatographic condition was feasible; short time for analysis and simple method were achieved. From score plot and loading plot of principle component analysis (PCA) , two rice cultivar samples were clearly separated, and it was revealed that Khao-Hom-Pathum was more suitable than Khao-Hom-Mali for cold pressed RBO production since it contained high total γ-oryzanol and less saturated free fatty acids. As with the fixed price of all the rice brans, this information can be used in order to, if possible, preserve the price of rice brans from different cultivars.