Nanoliposomal encapsulation of saffron bioactive compounds; characterization and optimization.

Nanoliposomes are among the most important lipid-based nanocarriers for both hydrophilic and hydrophobic bioactives. In this study, saffron-loaded nanoliposomes were produced by evaluating the influence of lecithin (0.5, 1.0, 1.5% w/w), saffron extract (0.15, 0.33, 0.50% w/w), and sunflower oil (25, 30, 35% w/w) on encapsulation efficiency, creaming stability, size and color indices of nanoliposomes. For each response, a second-order polynomial model with a high R2 value (0.950-0.989) was obtained using multiple linear regression analysis. The creaming stability revealed that when oil and saffron contents are enhanced, lecithin level was not enough for the formation of a stable network (reduction of surface tension) and thus stability was lowered. Dynamic light scattering results demonstrated nanoliposomal size of around 100 nm and polydispersity index (PDI) of 98.12 ± 0.11. Moreover, transmission electron microscopy (TEM) images illustrated spherical particles with a homogenous distribution and smooth surfaces. Also, lecithin level (P < 0.01), and saffron concentration (P < 0.05) significantly influenced the color indices, while sunflower oil content had no significant effect. Overall, the optimization results revealed that 0.15% saffron, 35% sunflower oil, and 1% lecithin was the optimum sample in terms of encapsulation efficiency, size and color indices.