Surface activities of monoacyl trehaloses in aqueous solution

Saturated and unsaturated fatty acids were condensed with trehalose using Candida antarctica lipase in an organic solvent to synthesize the corresponding monoacyl trehaloses. Their surface tension curves were measured at various concentrations and at different temperatures. The critical micelle concentrations, CMC, surface tension at the CMC, γ_CMC, and residual area per molecule, a, were estimated from the curves. The CMC of the saturated acyl trehaloses decreased as the acyl chain length increased at all temperatures. There was no significant dependency of the γ_CMC value on the chain length. The CMC values of the unsaturated monoacyl trehaloses having 18 carbon atoms in the acyl chain increased as the degree of unsaturation of the acyl chain increased. The a values were not affected by both the acyl chain length and the degree of unsaturation of the chain.