The Effects of Surfactant and Metal Ions on the Stability and Rheological Properties of Nanoemulsions Loaded with Gardenia Yellow Pigment

The present work reports the preparation of gardenia yellow pigment containing paraffin oil nanoemulsions stabilized by Span80 and Tween80. required was optimized testing different conditions, such as varying hydrophilic–lipophilic balance (HLB), emulsifier concentration (EC), oil–water ratio (OWR), temperature (T), determined average droplet diameter (ADD) polydispersity index (PDI). Our results indicated that a minimum ADD 65.9 nm PDI 0.116 were obtained at an optimum HLB value 6.0, EC 10% (w/w), OWR 2:1, T 40 °C. Both steady-state dynamic rheological parameters further investigated, revealing emulsions exhibited pseudoplastic behaviors. long-term stabilities after addition inorganic salts monitored observing their visual appearances. It found pure water or 0.1 M CaCl2 AlCl3 became slightly separated, while KCl NaCl showed no separation 30 days storage room T. This difference among could be related to number valence electrons cations. spatial electrostatic effects monovalent cationic (KCl NaCl) nonionic surfactants greater than delamination/sedimentation forces system, which better salt based on cations with valences one (CaCl2 AlCl3). In conclusion, illustrated formation, properties, stability in nanoemulsions, can great significance for application gardenia-yellow-pigment-based formulations.