Modeling phase separation and droplet size of W/O emulsions with oregano essential oil as a function of its formulation and homogenization conditions

ABSTRACT

Oregano essential oil emulsions (W/O) were prepared using different emulsifiers’ blend concentrations of Tween 80/Span 20, to study their phase separation during storage and to optimize the homogenization processing parameters by minimizing the droplet size of emulsions. Phase separation followed a second-order kinetic model, and relationships between the kinetic parameters and the blend concentrations of emulsifiers were established for determining the best emulsion formulations. The instability mechanism of emulsions demonstrated to be Ostwald ripening; therefore, by means of surface response methodology, mechanical homogenization parameters (11,700 rpm for 12 minutes at 1°C) were specified in order to minimize the droplet size of emulsions (1.02 ± 0.12 µm).

GRAPHICAL ABSTRACT

KEYWORDS:

• Emulsion phase separation kinetics
• oregano essential oil
• Ostwald ripening
• response surface methodology

Acknowledgments

Authors acknowledge the National Council for Science and Technology (CONACyT) of Mexico (project CB-2011, SEP-CONACyT, number 168709) and Universidad de las Americas Puebla (UDLAP) for the grant received for this research. Author Cardoso-Ugarte gratefully acknowledges CONACyT and UDLAP as well for the financial support for his PhD studies.

Additional information

Funding

This work was supported by the Consejo Nacional de Ciencia y Tecnología-a [Grant Number SEP-CONACyT, number 168709] and Universidad de las Américas Puebla (UDLAP) [Grant Number PhD Scholarship].