Encapsulation of anthocyanin in liposomes using supercritical carbon dioxide: Effects of anthocyanin and sterol concentrations

Anthocyanin-loaded liposomes were prepared via an improved supercritical carbon dioxide (SC-CO2) method. The effects of anthocyanin and cholesterol concentrations were studied in terms of the particle size distribution, encapsulation efficiency (EE), bioactive loading, morphology, zeta potential, anthocyanin-phospholipid interaction and in vitro release profiles. Anthocyanin-loaded liposomes had a particle size of 159 ± 0.2 nm, polydispersity index of 0.244 ± 0.02, EE of 50.6% and zeta potential of −40.2 mV. Elevated anthocyanin concentration increased the particle size with reduced uniformity due to enhanced electrostatic interactions and hydrogen bonding between anthocyanin and phospholipids. Liposomes exhibited unilamellar, spherical and near-spherical shapes with increased asymmetry and heterogeneity in the bilayer packing upon increased anthocyanin and cholesterol addition. The anthocyanin release from liposomes was slow (≤35.9%) in the simulated gastric fluid but rapid in the simulated intestinal fluid, induced by the degradation of the vesicles by pancreatin. Anthocyanin-loaded liposomes show great potential for functional food and nutraceutical applications.