Minimising oil droplet size using ultrasonic emulsification
T S H Leong1, T J Wooster, S E Kentish
1Particulate Fluids Processing Centre, Department of Chemical and Biomolecular Engineering and School of Chemistry, University of Melbourne, Parkville, Victoria 3010, Australia.
Ultrasonics Sonochemistry
|March 27, 2009
Summary
This study demonstrates the creation of transparent oil-in-water nanoemulsions with droplet sizes as low as 40nm using optimized ultrasound or high shear homogenization. Overpressure application further enhances nanoemulsion production efficiency.
Area of Science:
- Food science and technology
- Colloid and surface chemistry
- Materials science
Background:
- Efficient production of nanoemulsions with sub-100nm oil droplets is crucial for incorporating oil-soluble bioactive agents into water-based foods without altering product appearance.
- Small droplet sizes are essential for achieving transparent emulsions, maintaining the aesthetic qualities of food products.
Purpose of the Study:
- To demonstrate the creation of transparent oil-in-water (O/W) nanoemulsions with average diameters as low as 40nm using sunflower oil.
- To investigate the influence of surfactant/co-surfactant/oil systems, ultrasound, and high shear homogenization on nanoemulsion droplet size.
- To explore the impact of optimal droplet deformability and applied shear on achieving minimum droplet size and the effect of overpressure on production efficiency.
Main Methods:
- Utilized ultrasound or high shear homogenization techniques for nanoemulsion production.
- Employed an optimized surfactant/co-surfactant/oil system.
- Investigated the effect of droplet deformability (surfactant design) and applied shear (equipment geometry).
- Studied nanoemulsion production under atmospheric pressure and overpressure conditions (up to 400kPa).
Main Results:
- Achieved remarkably small transparent O/W nanoemulsions with average diameters as low as 40nm from sunflower oil.
- Minimum droplet size of 40nm was obtained only when both droplet deformability and applied shear were optimal.
- Production time was significantly affected by equipment configuration.
- Overpressure application (up to 400kPa) to the sonication vessel led to more efficient emulsion production compared to atmospheric pressure.
- Oil stability remained unaffected by the sonication process.
Conclusions:
- Optimized surfactant design and equipment geometry are critical for achieving ultra-small nanoemulsions.
- Overpressure is a viable method to enhance the efficiency of nanoemulsion production.
- The developed method allows for the incorporation of oil-soluble bioactive agents into food products without compromising visual appeal.
