Detection of synthetic food color “Metanil Yellow” in sweets: a systematic approach

Food adulteration is a primary global concern for public health, especially in developing countries, due to the lack of monitoring and appropriate policy developments and implementations. Synthetic colors and dyes are used to enhance the appearance of food products. Metanil Yellow (MY), a non-permitted, toxic, chief additive adulterant is majorly used in sweets, pulses, and turmeric in India owing to its color that ranges from yellow to orange. Owing to this, we have assessed the presence of MY in sweets like “jalebi” and “laddu” from branded and local vendors. We present a method to isolate the additive from the sweets with the help of acetic acid, followed by screening through colorimetric assay. The chemical characterization of MY was conducted using a multi-plate ultraviolet–visible (UV–Vis) spectrophotometer and attenuated total reflectance–Fourier transform infrared spectroscopy (ATR–FTIR). The appearance of magenta/pink color indicates the presence of MY in the chemical spot test. Also, thin-layer chromatography (TLC) was applied to validate the presence of this adulterant by comparing the peaks of reference (MY) with the extracted samples. TLC of food color extracted from the samples is an easy, efficient, and cost-effective method to detect toxic adulterants like MY. Our study demonstrates a simple food color extraction procedure, with easy and sensitive chemical assays, for the detection of MY in sweets. It also offers reasonable sensitivity and can be used to screen large numbers of samples in a short time.