Microemulsion-based lutein extraction from marigold petals: Process optimization and stabilization evaluation

In present study, a novel, efficient and environmental friendly microemulsion extraction method was established to extract lutein from marigold petals powder (MPP). The optimum microemulsion formulation was obtained by combining the screening of oils, co-surfactants and ternary phase diagram. Based on the saturation solubility of lutein, isoamyl acetate and n-propanol were selected as oil phase and co-surfactant, respectively. A 5 mL microemulsion consisting of Tween80/n-propanol/isoamyl acetate/water (36:36:18:10 wt%) was used for the extraction of lutein from 20 mg MPP, with the highest extraction efficiency of 95.17%. For lutein microemulsion, the average droplet size was 26.44 ± 0.17 nm, the polydispersity index was 0.37 ± 0.00 and Zeta potential was − 11.20 ± 0.26 mV. Compared with ethanol extract (EE), MPP microemulsion extract (LME) had higher stability under different temperature, pH, and storage time conditions. This study would provide a new alternative method for lutein extraction, and also could be expected to be applied for other poorly water-soluble ingredients.