Specific, sensitive and rapid Curcuma longa turmeric powder authentication in commercial food using loop-mediated isothermal nucleic acid amplification

Turmeric (Curcuma longa) is a rhizomatous plant of the ginger family Zingiberaceae that is usually dried and ground into powder for use as a seasoning. Because turmeric has become increasingly popular in the functional food market, adulteration of C. longa by other turmeric species is becoming an increasingly sig-nificant problem. In this study, loop-mediated isothermal amplification (LAMP) was developed for the detection of C. longa DNA for turmeric authentication. ITS2-26S rDNA was used for the LAMP primer des-ignation. The results demonstrated that the specific primers exhibited high specificity, authenticated C. longa DNA within 30 min at 65 degrees C isothermally and had no cross-reaction with other adulterants. LAMP was sensitive to 0.1 ng of turmeric C. longa DNA, and only 0.01% of C. longa turmeric powder in the sample was required for DNA amplification. The sensitivity of LAMP was 10-fold higher than that of PCR (0.1%) from a previous report. Moreover, all the collected commercial turmeric products were pos-itively detected by LAMP and RtF-LAMP (real-time fluorescence LAMP). The developed LAMP assay not only had higher specificity and rapidity than that of other methods but could also be applied to authen-ticate turmeric to prevent adulteration in food products. (c) 2021 The Author(s). Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

A loop-mediated isothermal amplification (LAMP) method was developed for detecting C. longa DNA, allowing rapid and accurate identification of turmeric and prevention of adulteration, with a sensitivity 10 times higher than PCR.