Development,rheological properties,and physical stability of d‐limonene‐in‐water emulsions formulated with copolymers as emulsifiers

This contribution reports the development of 30 wt % d ‐limonene‐in‐water emulsions formulated with a biopolymer (gellan gum) as stabilizer and prepared with a high‐pressure homogenizer. The role as emulsifiers of different ratios of amphiphilic copolymers (Atlas^TMG5000 and Atlox^TM4913) was assessed. The results indicated that the ratio of emulsifiers had significant effect on the physical stability, droplet size, viscoelasticity, and viscosity of these emulsions. The mean droplet diameters decreased as Atlas^TMG5000 concentration increased from 1 wt % to 3 wt %. The aging of emulsions resulted in an increase in the size of droplets for the emulsions containing high Atlox^TM4913 copolymer content. An increase of Atlas^TMG5000 enhanced both the G′ and G″ values and the viscosity providing higher stability to emulsions. Gellan gum caused in viscoelastic moduli weaker frequency dependence at the lower frequencies, according to the formation of a faint gel‐like matrix. All emulsions exhibited shear thinning flow properties that fitted the power‐law equation. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43838.