title: Evaluation of Turmeric Powder Adulterated with Metanil Yellow Using FT-Raman and FT-IR Spectroscopy.
abstract: Turmeric powder (Curcuma longaL.) is valued both for its medicinal properties and for its popular culinary use, such as being a component in curry powder. Due to its high demand in international trade, turmeric powder has been subject to economically driven, hazardous chemical adulteration. This study utilized Fourier Transform-Raman (FT-Raman) and Fourier Transform-Infra Red (FT-IR) spectroscopy as separate but complementary methods for detecting metanil yellow adulteration of turmeric powder. Sample mixtures of turmeric powder and metanil yellow were prepared at concentrations of 30%, 25%, 20%, 15%, 10%, 5%, 1%, and 0.01% (w/w). FT-Raman and FT-IR spectra were acquired for these mixture samples as well as for pure samples of turmeric powder and metanil yellow. Spectral analysis showed that the FT-IR method in this study could detect the metanil yellow at the 5% concentration, while the FT-Raman method appeared to be more sensitive and could detect the metanil yellow at the 1% concentration. Relationships between metanil yellow spectral peak intensities and metanil yellow concentration were established using representative peaks at FT-Raman 1406 cm-1and FT-IR 1140 cm-1with correlation coefficients of 0.93 and 0.95, respectively.
authors.affiliation: United States Department of Agriculture/Agricultural Research Service, Environmental Microbial and Food Safety Laboratory, Bldg. 303, Beltsville Agricultural Research Center East, 10300 Baltimore Ave., Beltsville, MD 20705-2350, USA. sagar.dhakal@ars.usda.gov.
authors.forename: Sagar
authors.initials: S
authors.lastname: Dhakal
authors.affiliation: United States Department of Agriculture/Agricultural Research Service, Environmental Microbial and Food Safety Laboratory, Bldg. 303, Beltsville Agricultural Research Center East, 10300 Baltimore Ave., Beltsville, MD 20705-2350, USA. kevin.chao@ars.usda.gov.
authors.forename: Kuanglin
authors.initials: K
authors.lastname: Chao
authors.affiliation: United States Department of Agriculture/Agricultural Research Service, Environmental Microbial and Food Safety Laboratory, Bldg. 303, Beltsville Agricultural Research Center East, 10300 Baltimore Ave., Beltsville, MD 20705-2350, USA. walter.schmidt@ars.usda.gov.
authors.forename: Walter
authors.initials: W
authors.lastname: Schmidt
authors.affiliation: United States Department of Agriculture/Agricultural Research Service, Environmental Microbial and Food Safety Laboratory, Bldg. 303, Beltsville Agricultural Research Center East, 10300 Baltimore Ave., Beltsville, MD 20705-2350, USA. jianwei.qin@ars.usda.gov.
authors.forename: Jianwei
authors.initials: J
authors.lastname: Qin
authors.affiliation: United States Department of Agriculture/Agricultural Research Service, Environmental Microbial and Food Safety Laboratory, Bldg. 303, Beltsville Agricultural Research Center East, 10300 Baltimore Ave., Beltsville, MD 20705-2350, USA. klchao@hotmail.com.
authors.forename: Moon
authors.initials: M
authors.lastname: Kim
authors.affiliation: United States Department of Agriculture/Agricultural Research Service, Environmental Microbial and Food Safety Laboratory, Bldg. 303, Beltsville Agricultural Research Center East, 10300 Baltimore Ave., Beltsville, MD 20705-2350, USA. diane.chan@ars.usda.gov.
authors.forename: Diane
authors.initials: D
authors.lastname: Chan
keywords: FT-IR; FT-Raman; metanil yellow; quantitative analysis; turmeric powder