Comparative surface activities of di- and trisaccharide fatty acid esters

Sucrose, maltose, leucrose, maltotriose, and beta-D-dodecylmaltoside fatty acid esters with acyl chains having 12 to 18 carbon atoms were enzymatically synthesized and their surface properties -critical micelle concentration, surface tension in water, and interfacial tension between water and xylene- were evaluated. The synthesized esters present critical micelle concentration (CMC) values in the range 2-250 muM with surface tension values ranging from 24.5 to 36.5 mN/m, and interfacial tension values from 1.0 to 9.4 mN/m depending on the compound. For the same acyl chain, CMC values were in the order maltotriose < leucrose < maltose < sucrose. The longest the fatty acid displays the lowest CMC, showing a decrease of one order of magnitude when the chain length was increased by six carbon atoms. beta-D-dodecylmaltoside monoesters exhibited high efficiency as water-in-oil emulsifiers. All the newly synthesized di- and trisaccharide-based surfactants displayed better surface-active properties and higher solubility compared with similar monosaccharide esters.