Glycerol polymerization degree effect on the emulsifying properties of polyglycerol esters

Polymeric emulsifiers based on glycerol and oleic acid were developed and their properties evaluated in palm oil and water solutions. Developed polymeric emulsifiers were polyglycerol‐esters. Polymerization degree of polyglycerol‐esters at different dosages (from 0.2 to 3% w/v) had a significant effect over emulsion stability, water surface tension, droplet size, and viscosity. Polyglycerol‐ester with highest polymerization degree behaved more efficiently as emulsifier. A dosage of 0.5% w/v was required to maintain emulsion stability for a half‐life period of 872 min (~14.5 h); which, is 5.6 and 3.6‐fold longer stability than with the other two polyglycerol‐esters developed. When dosage increased to 3% w/v, the emulsion stability also increased to 3792 min (~2.6 days). Nevertheless, surfactants with lower polymerization degree and molecular weight did not behave the same way. Emulsifier with highest polymerization degree reduced water surface tension by 70% and the mean particle diameter decreased when emulsifier polymerization degree increased. For the viscosity parameter, there were two interesting regions: for shear rates up to 1 s−1 the emulsion behaved as Non‐Newtonian fluid type Shear‐thinning; while, higher shear rates, the viscosity exhibited a Newtonian profile. The applications and properties of polymeric emulsifiers are strongly related to their structure. In this study, polyglycerol esters from glycerol and oleic acid were synthesized and effects of polymerization degree on the emulsifying properties were evaluated.