Eugenol Nanoemulsion Stabilized with Zein and Sodium Caseinate by Self-Assembly

Eugenol-loaded nanoemulsion by zein and sodium caseinate (NaCas) was prepared without using specific equipment or organic solvents. The deprotonated eugenol in hot alkaline was added to NaCas/zein mixtures with different mass ratios at pH 11.5 and then neutralized to pH 7.0. The nanoemulsions showed a well-defined diameter (around 109-139 nm) and a negative surface potential (from -28.5 to -35.8 mV) with spherical morphology. The entrapment efficiency (EE) of 1% (v/v) eugenol reached 84.24% by 2% (m/v) NaCas/zein at a mass ratio of 1:1. This formulation also showed the narrowest size distribution and extraordinary stability during ambient storage (22 °C) up to 30 days and retained good redispersibility after spray- or freeze-drying. The current study showed a promising clean and low-cost strategy to deliver lipophilic compounds containing the hydroxyl group.