Effect of type of fatty acid attached to sucrose ester on the stability of water-in-oil Pickering emulsion

Water-in-oil (W/O) Pickering emulsions have a broad range of potential for use in the food industries. However, because of the scarcity of edible W/O-type particles, the production and stabilization of W/O Pickering emulsion is challenged. Sucrose esters (SEs) have great promise as W/O-type particles, whose properties vary with fatty acid moiety attached. This study investigated the effect of fatty acid residue type on the interface activity of SE and corresponding emulsion properties, in order to select the most suitable SE. Sucrose stearate (SE-S), sucrose palmitate (SE-P), sucrose laurate (SE-L), sucrose erucic acid ester (SE-E) and sucrose oleate (SE-O) were applied. Results showed that the saturation of fatty acid residues caused the difference of crystallinity of SE: SE-S＞SE-P＞SE-L＞SE-E＞SE-O. The lower crystallinity resulted in the increased hydrophilicity of SE-O with a closer θ (101.4°) to 90°, which facilitated interfacial adsorption and rearrangement, and larger decrease of interfacial tension (3.93 mN/m). Consequently, SE-O was capable of stabilizing more water volume fraction (75%). Moreover, the emulsion stabilized by SE-O was observed smaller droplet sizes, higher gel strength, and physical stability. The results revealed that SE-O was more appropriate for the preparation of W/O Pickering emulsion.