Characterization of E 472 food emulsifiers by high-performance thin-layer chromatography with fluorescence detection and mass spectrometry.

Esters of fruit acids including acetic acid and mono- and diacylglycerols (MAG and DAG), also known as E 472 emulsifiers, are used in the food industry as food additives to adjust techno-functional properties like viscosity, emulsion stability and foaming stability in various products, mainly dairy products. Based on the respective acids, E 472 emulsifiers are classified in several categories with acetic acid esters (ACETEM, E 472a), lactic acid esters (LACTEM, E 472b), citric acid esters (CITREM, E 472c), and mono- and diacetyl tartaric acid esters (DATEM, E 472e) as the most prominent representatives. Besides fruit acid esters, E 472 emulsifiers mainly comprise MAG, DAG, triacylglycerols, free fatty acids, free fruit acids and free glycerol in different amounts. Here we present an innovative and sensitive method for the characterization of the composition of E 472 emulsifiers by high-performance thin-layer chromatography with fluorescence detection (HPTLC-FLD). For HPTLC-FLD, technical emulsifiers were simply dissolved and analyzed on HPTLC silica gel plates after a two-fold development and derivatization with primuline, enabling the easy characterization and direct visual comparison of the emulsifier pattern (fingerprint) through the fluorescent lipid components under UV 366 nm. Thus, the HPTLC-FLD fingerprint approach represents a simple tool for the comparison of different samples, batches and categories of E 472. Coupling of HPTLC to mass spectrometry moreover enabled the identification of constituents of interest.