Effects of surfactants on the physical properties of capsicum oleoresin-loaded nanocapsules formulated through the emulsion–diffusion method

Capsicum oleoresin encapsulation by poly-ε-caprolactone (PCL) was investigated using the emulsification–diffusion method. Here, the emulsifier concentration affected the characteristics of both the nanoemulsion (NE) and nanocapsules (NCs). The process parameters were optimized by varying the Pluronic® F68 (PF68) concentration in the aqueous phase of the formulation. In this research, the optimal parameters of the preparation process were established, and the physical properties of NE and NC were compared. The size of the NC particles decreased according to an increase in the emulsifier concentration. NE showed insignificantly different particle sizes with mean diameters of 320–460 nm depending on the emulsifier concentration. On the contrary, the size of the NC particles prepared with 1.25% PF68 was 5.43 ± 0.29 μm, while the NC with 5% PF68 produced smaller particles (310 nm). The surfactant concentration also had an important effect on the encapsulation efficiency and release properties of the NCs while maintaining the loading capacity of the capsicum oleoresin.