Minimising oil droplet size using ultrasonic emulsification

Abstract

The efficient production of nanoemulsions, with oil droplet sizes of less than 100nm would facilitate the inclusion of oil soluble bio-active agents into a range of water based foods. Small droplet sizes lead to transparent emulsions so that product appearance is not altered by the addition of an oil phase. In this paper, we demonstrate that it is possible to create remarkably small transparent O/W nanoemulsions with average diameters as low as 40nm from sunflower oil. This is achieved using ultrasound or high shear homogenization and a surfactant/co-surfactant/oil system that is well optimised. The minimum droplet size of 40nm, was only obtained when both droplet deformability (surfactant design) and the applied shear (equipment geometry) were optimal. The time required to achieve the minimum droplet size was also clearly affected by the equipment configuration. Results at atmospheric pressure fitted an expected exponential relationship with the total energy density. However, we found that this relationship changes when an overpressure of up to 400kPa is applied to the sonication vessel, leading to more efficient emulsion production. Oil stability is unaffected by the sonication process.

Production of Tocols Nanoemulsion by Ultrasonication

“…When sonication amplitude increased from 60%-100%, there is a reduction of droplet size from 136.1 ± 2.5 nm to 108.6 ± 0.4 nm due to cavitation ( Figure 1). The intensity of cavitation activity in emulsifying tocols is proportional to sonication amplitude (Leong et al, 2009). Emulsions sonicated at three different amplitudes showed that mean droplet diameter decreases with sonication time.…”

Formation of the steam phase in superheated liquids in the state of metastable equilibrium

“…The processes of deformation and fragmentation of the dispersed phase have been considered in [21][22][23][24][25][26][27][28][29][30] but these processes are still not fully understood and require large energy consumptions for their practical realization.…”

Dynamic Study of Water Droplets in Two Phase Liquid by Ultrasound

“…The R-P equation [2] is modified by introducing the acoustic radiation factor by Prospertti A., but these are the motions of tiny bubbles in the liquid. In the real life, the two-phase system of liquid-liquid two-phase system or membrane isolation under ultrasonic action is often encountered, such as: ultrasonic catalytic emulsification system [3], ultrasound in the life of the cell membrane in the transport of substances and energy transmission [4], how the ultrasound effect of soft matter droplets (such as: gels, vesicles, etc.) will be change?…”