Characterization of E 471 food emulsifiers by high-performance thin-layer chromatography-fluorescence detection

Area of Science:

• Food Chemistry
• Analytical Chemistry
• Chromatography

Background:

• Mono- and diacylglycerol (MAG and DAG) emulsifiers, designated as food additive E 471, are crucial for modifying food techno-functional properties.
• These emulsifiers often contain varying proportions of triacylglycerols (TAGs) and free fatty acids (FFAs) alongside MAGs and DAGs.
• Conventional analysis of these lipid classes typically involves high-performance liquid chromatography (HPLC) or gas chromatography (GC) coupled with mass selective detection.

Purpose of the Study:

• To develop and validate a rapid and sensitive method for determining MAGs, DAGs, TAGs, and FFAs in E 471 emulsifiers.
• To establish a response factor system for accurate quantitation using the developed method.
• To present high-performance thin-layer chromatography with fluorescence detection (HPTLC-FLD) as a viable alternative to HPLC and GC.

Main Methods:

• Samples were dissolved and diluted in t-butyl methyl ether.
• A two-fold chromatographic development was performed on silica gel plates using specific mobile phases.
• Quantitation was achieved by scanning the plate in fluorescence mode (UV 366/>400 nm) and utilizing cumulative signals for each lipid class, calibrated with 1,2-distearin.

Main Results:

• The HPTLC-FLD method demonstrated high sensitivity with limits of detection and quantitation of 1 and 4 ng/zone for 1,2-distearin, respectively.
• Lipid class amounts were calculated using response factors and expressed as specific fatty acid derivatives (monostearin, distearin, tristearin, stearic acid).
• The method allows for visual characterization and direct comparison of emulsifiers via their lipid class fingerprint.

Conclusions:

• The HPTLC-FLD approach provides a simple, rapid, and convenient screening method for analyzing lipid classes in E 471 emulsifiers.
• This technique serves as an effective alternative to more complex HPLC and GC analyses.
• Visual detection offers an additional advantage for easy characterization and comparison of emulsifier samples.