Zeta potential and drop growth of oil in water emulsions stabilized with mesquite gum

The influence of the nature of the oil phase on the zeta potential and the time course evolution of mean droplet-size of emulsions stabilized with mesquite gum have been investigated. Mesquite gum-stabilized emulsions of d-limonene, n-decane, n-dodecane, n-tetradecane n-hexadecane, and orange oil were prepared in the range of 9–22% w/w mesquite gum concentrations to investigate the emulsion stability by analyzing creaming, zeta potential, and drop size distribution. An electrosteric mechanism of stabilization is proposed to explain the long term stability observed for orange oil–water emulsions in the range of 9–22% w/w mesquite gum concentrations, similar to the one suggested to operate for gum arabic interfaces. Experiments of creaming for the different emulsions, showed that orange oil–water emulsions observed strong stability in time. By contrast, mesquite gum-stabilized emulsions of d-limonene, n-decane, n-dodecane, n-tetradecane, and n-hexadecane produced less stable emulsions. Light scattering measurements were performed to analyse the Ostwald ripening phenomenon on diluted oil in water emulsions stabilized with mesquite gum of n-hexadecane, d-limonene, and orange oil. The averaged hydrodynamic radius showed a linear-like behavior with time except for orange oil drops which kept their size almost constant for more than hundred hours.