ABSTRACT
Thin-layer chromatography (TLC) is an important method for the analysis of synthetic and natural colorants in foods, which in this chapter include foodstuffs, beverages, functional foods, and dietary supplements. This chapter presents the literature from 2007 to 2018 in order to update three earlier reviews on the analysis of natural colorings in foods by TLC, published in 2007, chromatographic methods for the determination of synthetic food dyes, in which the latest TLC reference cited was published in 2006, and methods for the determination of European Union-permitted natural colors in foods, with one cited TLC reference published in 2009 and all others in 2005 or earlier. Colorants are usually extracted from foods prior to TLC by using an appropriate solvent, with traditional techniques such as shake, homogenization, Soxhlet, membrane filtration, and ultrasound-assisted extraction. Sample and standard solutions are applied manually to the plate as spots, with the help of a micropipette, or automatically, as bands or spots, with a commercial instrument.
