Characterization and rheological behavior of vitamin E nanoemulsions prepared by phase inversion composition technique

Abstract

Many food, pharmaceutical, and cosmetic products are fabricated as nanoemulsions of vitamin E, a vital food micronutrient soluble in oil. Nanoemulsion production, maintenance, and application depend on physicochemical characteristics and rheology. Therefore in this work, we prepared Vitamin E nanoemulsions by the phase inversion composition technique and investigated its physical and rheological characteristics at varied stirring speeds. The nanoemulsions' mean droplet sizes, confined to 5.77 to 11.89 nm, surprisingly showed two different flow behavior regimes: at low-shear rates, Pseudoplastic behavior, and at high-shear rates, Newtonian behavior. Furthermore, their viscosity in high shear rate regimes increased with droplet size. The nanoemulsions exhibited linear viscoelasticity, with storage modulus and loss modulus varying with frequency, and showed concentrated solution behavior, with a storage modulus larger than the loss modulus at higher frequencies. After 30 days of storage, larger droplet-size nanoemulsions showed a more significant viscosity and loss modulus reduction than smaller droplet-size nanoemulsions. This study on Vitamin E nanoemulsions' flow behavior will help develop oil-soluble vitamin delivery applications.

Keywords

• Vitamin E nanoemulsion
• Droplet size
• Non-Newtonian fluid
• Viscoelasticity