Edible oil-water foamulsions stabilized by vesicle network of sucrose ester

Abstract

Foamulsions are tri-phase dispersions consisting of oil, water and gas. The stabilizers of foamulsions are typically single surfactants or their mixtures. However, foamulsions stabilized by molecular surfactants are usually unstable against long term storage. In this work we report that a nonionic surfactant, sucrose stearate C-1807 (HLB = 7), can be a good stabilizer for foamulsions prepared with edible oils such as canola oil and soybean oil. It is found that C-1807 forms spherical vesicles in water which develop further to a vesicle network at concentrations beyond 3 wt%, increasing significantly the viscosity of the aqueous phase. Normally, the presence of oil is unfavourable for the stabilization of foams, however long-term stable foamulsions can be attained due to the highly viscous continuous phase as well as the presence of vesicles around oil droplets and air bubbles which inhibits their coalescence. The foamulsions are stable against cooling-heating cycles (5 °C to 30 °C) though partially unstable during freeze-thaw cycles (−20 °C to 30 °C). The stabilization of foamulsions by sucrose ester applies to different edible oils, and C-1807 as a non-toxic and biodegradable surfactant may act as a fat replacer in developing healthy foods such as low fat cream or butter.