Detection of Additives and Chemical Contaminants in Turmeric Powder Using FT-IR Spectroscopy

• Published in: Foods Vol. 8; no. 5; p. 143
• Main Authors: Dhakal, Sagar, Schmidt, Walter F, Kim, Moon, Tang, Xiuying, Peng, Yankun, Chao, Kuanglin
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI 26.04.2019; MDPI AG
• Subjects: adulteration; curcumin; food safety; FT-IR; Sudan dye; turmeric; white turmeric; food safety; Sudan dye; adulteration; white turmeric; FT-IR; turmeric; curcumin
• ISSN: 2304-8158; 2304-8158
• DOI: 10.3390/foods8050143

Yellow turmeric ( ) is widely used for culinary and medicinal purposes, and as a dietary supplement. Due to the commercial popularity of , economic adulteration and contamination with botanical additives and chemical substances has increased. This study used FT-IR spectroscopy for identifying and estimating white turmeric ( ), and Sudan Red G dye mixed with yellow turmeric powder. Fifty replicates of yellow turmeric-Sudan Red mixed samples (1%, 5%, 10%, 15%, 20%, 25% Sudan Red, / ) and fifty replicates of yellow turmeric-white turmeric mixed samples (10%, 20%, 30%, 40%, 50% white turmeric, / ) were prepared. The IR spectra of the pure compounds and mixtures were analyzed. The 748 cm Sudan Red peak and the 1078 cm white turmeric peak were used as spectral fingerprints. A partial least square regression (PLSR) model was developed for each mixture type to estimate adulteration concentrations. The coefficient of determination (R ) for the Sudan Red mixture model was 0.97 with a root mean square error of prediction (RMSEP) equal to 1.3%. R and RMSEP for the white turmeric model were 0.95 and 3.0%, respectively. Our results indicate that the method developed in this study can be used to identify and quantify yellow turmeric powder adulteration.