TURMERIC IDENTIFICATION AND ADULTERATION DETECTION BY DIGITAL COLOROMETRY AND NEAR-IR SPECTROSCOPY METHODS

The possibility to identify and establish the fact of turmeric adulteration by simple and affordable methods using methods of infrared spectroscopy, digital colorometry and chemometric processing of spectral data was shown. Near-infrared spectroscopy was used to differentiate between samples of turmeric powder purchased in India, made by grinding the roots, and commercial samples, and to separate them from samples with impurities of flour, starch, breadcrumb and chalk by analyzing diffuse reflectance spectra using principal component methods, hierarchical cluster analysis and formal independent class analogy modeling. The same approaches were applied to the simpler and less costly colorometric method. Chemometric processing of the obtained data confirmed the lack of similarity of the analyzed turmeric samples with samples containing additives and allowed the determination of impurities using multivariate regression analysis algorithms. Comparison of the results obtained by IR spectroscopy and digital colorometry showed their equivalent efficiency, which allowed us to recommend the more affordable colorometric method for routine quality control and detection of turmeric adulteration.