Formulation-dependent colloidal properties of redispersible lycopene nanoparticles: storage stability and enhanced

Lycopene is a bioactive carotenoid whose application is limited by poor aqueous dispersibility and susceptibility to degradation. Redispersible lycopene nanoparticles were prepared by solvent displacement-evaporation followed by freeze-drying, and interfacial composition and nominal lycopene fraction were evaluated sequentially. Among the tested interfacial compositions, a 2 : 1 Tween 80/phosphatidylcholine mass ratio produced the smallest particles and lowest dispersity. At this ratio, the formulation containing 12 wt% nominal lycopene was selected for its balance of lycopene content, particle size, and dispersity. The measured lycopene content of the freeze-dried formulation was 11.63 wt%; after aqueous redispersion, the particles exhibited a mean hydrodynamic diameter of 133.25 ± 1.46 nm, a polydispersity index of 0.173 ± 0.016, and a zeta potential of -38.3 ± 1.9 mV. TEM showed predominantly near-spherical particles. FTIR spectra were consistent with physical incorporation in the matrix, while XRD showed marked attenuation of crystalline lycopene reflections. The redispersed formulation maintained its colloidal characteristics for 7 days at 4 °C, and the freeze-dried formulation retained 91.9% of its initial lycopene content after 180 days at -20 °C. At matched lycopene doses, the formulation showed higher apparent DPPH radical-scavenging activity and greater protection against H