The effect of different concentrations of tween-20 combined with rice husk silica on the stability of o/w emulsion: A kinetic study

Emulsion is a thermodynamically unstable system which undergoes destabilization with time. The destabilization kinetics of "food grade" oil-in-water (O/W) emulsions in the presence of both tween-20 and rice husk silica as emulsifiers were studied. Rice husk silica concentration of 2.5% was combined with various concentrations of tween-20 from 0.1 to 1%. Oil phase fraction was 20% relative to the aqueous phase. Emulsification was conducted using a rotor-stator homogenizer at 20,000 rpm. The emulsions tended to destabilize with time. Their destabilization rates were studied using zero order and first order kinetic models. In general, the kinetics of O/W emulsion destabilization followed first order model. Different concentrations of tween-20 combined with rice husk silica influenced the destabilization rate of o/w emulsions. Destabilization rates of emulsions stabilized using mixed emulsifiers of 1% tween-20 and 2.5% silica were ∼50 times and ∼3 times lower compared to those stabilized using silica alone and tween-20 alone, respectively.