COMPARISON OF FOAMING AND INTERFACIAL PROPERTIES OF PURE SUCROSE MONOLAURATES, DILAURATE AND COMMERCIAL PREPARATIONS

The functional properties of a commercially available, crude sucrose m onolaurate (L1695) were studied by investigating the foaming, and inte rfacial properties, i.e. surface tension, thin film drainage, thicknes s and mobility, and comparing them with the properties of pure sucrose monolaurate isomers and sucrose dilaurate. Both pure sucrose monoeste r 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 f oamability and foam stability than either component. Addition of diest er to monoester improved the foaming properties of the monoester to th at of the crude sample, with the optimum enhancement observed at a mol ar ratio of 4:1 (monoester:diester). Little or no differences in surfa ce tension and thin film properties were observed between monoester an d mono/diester mixtures. Initial work studying aggregation showed an i ncrease in light scattering and a reduction in critical micelle concen tration with sucrose mono/diester (molar ratio 4:1). The functional pr operties 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. Simi lar foam stability was observed for the purified monoesters and monoes ter/diester mixture in the presence of BSA whereas the foam stability of crude sucrose monoester was dependent on the presence of surface ac tive contaminants (i.e. fatty acid) within the commercial sucrose este r. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.