Construction of Slow Digestion Coconut Oil Emulsion System Series and Comparison of Their Microrheological Properties and in Vitro Digestive Properties

In this paper,coconut oil single-layer emulsion was prepared using coconut oil as the core material and whey protein isolate(WPI) as the wall material,respectively. And four types of double-layer emulsions were prepared using coconut oil single-layer emulsion as the core material and CMC,CNC,CNI,MCC as the wall material,respectively. The microrheological and in vitro digestive properties of all emulsion systems was studied. The results showed that WPI-CNC stabilized coconut oil emulsion systems had the highest macroscopic viscosity index and elasticity index(P<0.05),and the droplets in the emulsion were not free to move due to the droplets network interaction. The WPI-CNC emulsion had the lowest SLB value(P<0.05),and the rate of droplets movement in the emulsion was low. WPI-CNC emulsion had a lowest intestinal release rate and the slowest release rate. Following passage through the simulated stomach phase,extensive droplet flocculation was observed except coconut oil emulsion stabilized by WPI-CNC,and the degree of aggregation was increased following exposure to the simulated small intestinal stage. Following exposure to the simulated mouth,stomach and small intestinal stage,we observed an ordinal increase in the mean particle size of WPI,WPI-CNC and WPI-CMC emulsions,and the particle size distribution demonstrated that these emulsions exhibited multimodal distribution. Following exposure to the simulated small intestinal stage,increase in the negative charge of all emulsions was observed. It demonstrated that the microrheological property of coconut oil emulsion significantly affected their digestibility,and WPI-CNC stabilized coconut oil emulsion had the lowest and the slowest digestibility in vitro.