1H NMR spectroscopy combined with chemometrics for detection of turmeric adulteration in Italian saffron (Crocus sativus L.)

Saffron, derived from the stigmas of Crocus sativus L., is a high-valued spice often adulterated due to its high price and economic profit. Among adulterants, one of the most common is turmeric (Curcuma longa L.). Detecting saffron adulteration with untargeted and non-destructive analytical approaches is important for food authenticity. In our study, 400 MHz proton NMR spectroscopy was used to analyse 138 extracts of authentic saffron and saffron adulterated with turmeric at three levels (2.5, 5 and 10 % w/w). Chemometric classification using Partial Least Squares Discriminant Analysis enabled discrimination between pure and adulterated saffron samples, with classification sensitivity of 98 % for pure saffron and 95 % for adulterated samples. This approach successfully detected adulteration at levels as low as 2.5 %, demonstrating the potential of 1H NMR combined with multivariate analysis for saffron authenticity assessment, even at low concentrations of adulterants.