Analysis of β-carotene and paprika color in foods using reversed-phase thin-layer chromatography/scanning densitometry

Abstract

A technique for the analysis of β-carotene and paprika color in foods using reversed-phase TLC and scanning densitometry was established. Both colors were extracted with ethyl ether from foods. Extract of β-carotene was directly cleaned up with a C18 cartridge and extract of paprika color was cleaned up with a C18 cartridge after saponification with 5% sodium hydroxide in methanol. Separation of both extracts was achieved on the reversed-phase C18 TLC plate using acetonitrile-acetone-n-hexane (11: 7: 2) as the solvent system. The visible absorption spectra of the extracts were measured using scanning densitometry without isolation of the colors. In order to investigate the capability of the present method, 77 commercial foods were analyzed, and their chromatographic behaviors and spectra were observed. The separation and the spectra obtained were not affected by coexisting substances in the foods and the spots always gave the same Rf values and spectra as the standards, with good reproducibility. The present method is considered to be useful for the rapid analysis of β-carotene and paprika color in foods.