Premix membrane emulsification for the preparation of curcumin-loaded nanoemulsions

In order to overcome limitations of conventional methods, premix membrane emulsification (ME) using Shirasu porous glass (SPG) membranes was investigated for the preparation of O/W food-grade nanoemulsions. In this study, the effects of major emulsification process variables, formulation and membrane parameters on the mean droplet diameter and polydispersity (PDI) were systematically investigated. Stability of curcumin-loaded nanoemulsions with different size was also investigated during 28 days storage period. The results revealed that surfactant type and concentration, and medium-chain triglyceride (MCT) concentration played an important role on droplet size and PDI values, while premix quality, flow rate and cycle number had a minor effect on the droplet size. Moreover, there was a linear relationship between the membrane pore size and mean droplets size of nanoemulsions. Curcumin-loaded nanoemulsions with high encapsulation efficiency (>94%) had a good stability (>96% retention rate) after 28 days of storage at 4 degrees C. Also, there were no major differences on the retention rate of curcumin for nanoemulsions with different droplet size when they were stored at 4 degrees C, 25 degrees C and 37 degrees C under both pH 3 and pH 7. These results indicated that premix ME can be successfully used for the preparation of food-grade nanoemulsions with controlled droplet sizes and narrow droplet size distributions.