Quantitative analysis of Sudan dye adulteration in paprika powder using FTIR spectroscopy

Authors: LOHUMI, SANTOSH - Chungnam National University; JOSHI, RITY - Chungnam National University; KANDPAL, LALIT - Chungnam National University; Kim, Moon; CHO, HYUNJEONG - Us Forest Service (FS); MO, CHANGYEUN - Rural Development Administration - Korea; SEO, YOUNG-WOOK - Chungnam National University; RAHMAN, ANISUR - Chungnam National University; CHO, BYOUNG-KWAN - Chungnam National University

Submitted to: Journal of Food Additives & Contaminants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/16/2017
Publication Date: 7/31/2017
Citation: Lohumi, S., Joshi, R., Kandpal, L.M., Kim, M.S., Cho, H., Mo, C., Seo, Y., Rahman, A., Cho, B. 2017. Quantitative analysis of Sudan dye adulteration in paprika powder using FTIR spectroscopy. Journal of Food Additives & Contaminants. 34(5):678-686.

Interpretive Summary: Incidents of food adulteration have raised public concerns for safety and quality in recent years. Synthetic dyes have been widely used as coloring agents in the food industry for many years. Among these dyes, red-orange colored Sudan dyes are often used for coloring purposes to enhance food appearance and hence to promote sales. In this research, the feasibility of using Fourier transform infrared (FTIR) spectroscopy to rapidly detect Sudan dye in paprika powder was investigated. Using a multivariate analysis model, the spectral method could identify paprika powder adulterated with Sudan dye with approximately 97% accuracy. Compared to conventional methods based on liquid chromatography, this spectral technique has advantages of rapidity, simplicity, and solvent-free processing, providing a potential tool for detecting adulteration that can be useful to food producers and processors interested in preventing and detecting adulteration of foods.

Technical Abstract: The presence of Sudan dye used illegally for coloring in food stuffs has become a point of food safety concern, especially in paprika- and chili-containing food products. Fourier transform infrared (FTIR) spectroscopy has been extensively used as an analytical method for quality control and safety measurement of food products. The feasibility of using FTIR spectroscopy for rapid determination of Sudan dye in paprika powder was investigated in this study. A net analyte signal (NAS) based methodology called HLA/GO (hybrid linear analysis presented by Goicoechea and Olivieri) was applied to FTIR spectral data for predicting Sudan dye concentration in paprika powder. The calibration and validation data sets were designed to evaluate the performance of the multivariate method. The results obtained show a high determination coefficient (R2) of 0.98 and low Root mean square error (RMSE) of 0.026% for the calibration set, and R2 of 0.97 and RMSE of 0.05% for the validation set. The model was further validated using a second validation set, and through the figures of merit such as sensitivity, selectivity, limit of detection and quantification. The proposed technique of FTIR combined with multivariate calibration method HLA/GO for detecting Sudan dye presents advantages of rapidity, simplicity, low cost, and solvent-free processing, when compared to the main alternative detection methods based on liquid chromatography.