Various fatty monoesters of sugars and sugar alcohols were prepared en
zymatically in organic solvent. Water produced during esterification w
as removed by refluxing through a dessicant under reduced pressure. Su
rface properties of these esters such as surface and interfacial tensi
ons and their ability to stabilize emulsions at 30 degrees C were eval
uated: oleate esters of glucose, fructose, and sorbitol show similar b
ehavior in reduction of surface and interfacial tensions, and values f
or the critical micelle concentration are about 8 . 10(-5) M. It was a
lso observed with sorbitol esters that the shorter the alkyl chain, th
e higher the critical micelle concentration. Generally, emulsions prep
ared with the emulsifier dissolved in the water or in the oil phase le
ad to oil-in-water or water-in-oil emulsions, respectively. Sorbitol m
onolaurate significantly increased the stability of oil-in-water emuls
ions, with only 5% separation of the phases after 48 h at 30 degrees C
, compared to 10% for chemically prepared sorbitan monolaurate under t
he same conditions. Sorbitol monoerucate was very efficient in stabili
zing water-in-oil emulsions, with only 1% separation of the phases.