Differentiation of white rice Khao Dawk Mali 105 (KDML105) from other Thaiwhite rice using FTIR microscope-attenuated total reflectance-focal plane arraydetector

Thai Hom Mali rice is one of Thailand’s most important agricultural products, due to its higher commercial value compared to other rice, both domestically and internationally. A higher ratio of other white rice varieties is frequently found in white rice Thai Hom Mali affects consumer confidence since there is no fast procedure for differentiation of Thai Hom Mali Rice from other rice varieties, for this reason, this research proposed a spectroscopic analysis method to investigate the biochemical content of rice samples for distinguishing Thai Hom Mali Rice from other rice varieties. The absorbance spectrum of five Thai rice varieties was identified: Khao Dawk Mali 105 (KDML105), Pathum Thani 1 (PTT1), RD77, Chai Nat 1 (CN1), and Phitsanulok 2 (PLS2). The FTIR-microscopeattenuated total reflectance-focal plane array detector (FTIR-microscope-ATR-FPA detector) was applied to acquire the bandwidth of the mid-wavelength infrared (3800-900 cm-1 ). According to the spectroscopic data, the absorbance spectrum of KDML105 rice contained a strong intensity to identify the wavenumber at 1250 and 1748 cm-1 representing the vibrational mode of C–N stretching in aromatic amine and C=O stretch in ester compounds, respectively. The rice varieties were classified using principal component analysis (PCA) to identify the wavenumber and separate the KDML105 rice from other rice varieties with PC1 achieving more than 82% for individual analysis and more than 40% for overall analysis, respectively.