The influence of non-ionic surfactant on lipid digestion of gum Arabic stabilized oil-in-water emulsion

Abstract

Lipid digestion is the process of enzymatic hydrolysis at the interface, and the interfacial structure play an important role in the lipid digestion. Non-ionic surfactant Tween80 (T80) presented a significant impact on the lipid digestion of gum Arabic (GA) stabilized oil-in-water emulsion. The interfacial structure of GA-T80 emulsion droplets has been investigated by using gel permeation chromatography-multiangle laser light scattering, interfacial measurement and atomic force microscope. With addition of T80, the surface loading of GA decreased until a plateau value reached. About 15% of GA still remained on the interface when T80 concentration increased to ∼4%. Addition of T80 contributed to a stiffening of the network formed at the droplets interface. The kinetics of lipid digestion exhibited a biphasic rate under this certain interface, shown as an induction period followed by a speeding up process. It probably resulted from the adsorption behavior of lipase on the emulsion interface during the lipolysis process. In was found that the accumulation of lipase on the emulsion droplets interface contributed to the lag period of the free fatty acids release. The biphasic rate of lipid digestion was mainly caused by the rate of lipase adsorption, which was highly dependent on the interface structure of emulsion droplets.