Barcoding Melting Curve Analysis for Rapid, Sensitive, and Discriminating Authentication of Saffron (Crocus sativusL.) from Its Adulterants

Abstract

Saffron (Crocus sativusL.) is one of the most important and expensive medicinal spice products in the world. Because of its high market value and premium price, saffron is often adulterated through the incorporation of other materials, such asCarthamus tinctoriusL. andCalendula officinalisL. flowers,HemerocallisL. petals,Daucus carotaL. fleshy root,Curcuma longaL. rhizomes,Zea mayL., andNelumbo nuciferaGaertn. stigmas. To develop a straightforward, nonsequencing method for rapid, sensitive, and discriminating detection of these adulterants in traded saffron, we report here the application of a barcoding melting curve analysis method (Bar-MCA) that uses the universal chloroplast plant DNA barcoding regiontrnH-psbAto identify adulterants. When amplified at DNA concentrations and annealing temperatures optimized for the curve analysis, peaks were formed at specific locations for saffron (81.92°C) and the adulterants:D. carota(81.60°C),C. tinctorius(80.10°C),C. officinalis(79.92°C),Dendranthema morifolium(Ramat.) Tzvel. (79.62°C),N. nucifera(80.58°C),Hemerocallis fulva(L.) L. (84.78°C), andZ. mays(84.33°C). The constructed melting curves for saffron and its adulterants have significantly different peak locations or shapes. In conclusion, Bar-MCA could be a faster and more cost-effective method to authenticate saffron and detect its adulterants.