Comparison of foaming and interfacial properties of pure sucrose monolaurates, dilaurate and commercial preparations

Abstract

The functional properties of a commercially available, crude sucrose monolaurate (L1695) were studied by investigating the foaming, and interfacial properties i.e. surface tension, thin film drainage, thickness and mobility, and comparing them with the properties of pure sucrose monolaurate isomers and sucrose dilaurate. Both pure sucrose monoester isomers studied exhibited similar foaming and interfacial properties. In comparison, sucrose dilaurate displayed poorer foaming properties and higher surface tension. Crude sucrose monolaurate had a greater foamability and foam stability than either component. Addition of diester to monoester improved the foaming properties of the monoester to that of the crude sample, with the optimum enhancement observed at a molar ratio of 4:1 (monoesterrdiester). Little or no differences in surface tension and thin film properties were observed between monoester and mono/diester mixtures. Initial work studying aggregation showed an increase in light scattering and a reduction in critical micelle concentration with sucrose mono/diester (molar ratio 4:1). The functional properties of both the crude sucrose monoester and major components were also investigated in the presence of protein. The foamability of all the sucrose esters in the presence of BSA showed a similar trend. Similar foam stability was observed for the purified monoesters and monoester/diester mixture in the presence of BSA whereas the foam stability of crude sucrose monoester was dependent on the presence of surface active contaminants (i.e. fatty acid) within the commercial sucrose ester Abbreviations: sucrose 6-monolaurate (SE6L); sucrose 6′-monolaurate (SE6′L); crude sucrose ester laurate (CSEL); sucrose dilaurate (SEDL); fluorescent recovery after photobleaching (FRAP); 5-dodecanoylaminofluorescein (DDAF), molar ratio (MR); (hydrophiliclipophilic balance HLB); absorbance at 350 nm (A 350); critical micelle concentration (CMC); gas chromatography (GC).