High-intensity ultrasound (HIU) has been employed within edible lipids to accelerate the crystallisation process and to enhance the physicochemical properties of the resulting solid. Several studies have highlighted the significance of the generation of gas cavities during sonication, however acoustic cavitation has received little research interest for lipids. High-speed imaging has shown that the dynamics of a stable cavitation cluster next to a piston-like emitter (PLE) are driven by the HIU power level. The kinetics of lipid crystallisation for a sequence of cavitation clusters within an all-purpose shortening sample were investigated. The influence of the cluster dynamics upon the crystallisation kinetics is shown to become less significant for greater lipid supercooling at 26 °C compared to 30 °C. In addition, a bifurcated streamer consisting of two cavitation clusters that oscillate with a relative phase shift of 180° with respect to one another was explored. This unusual ‘bi-cluster’, formed at a HIU power of 10 W, is shown to reduce the induction time of crystallisation by ~8 minutes with respect to the untreated lipid sample. This was comparable to higher HIU powers of up to 36 W. Finally, an increase in the hardness of the lipid sample was noted. The greatest hardness was reported in the presence of a cavitation cluster with the lowest frequency of oscillation. These results indicate the importance of studying cluster dynamics to enable a greater understanding of the lipid sonocrystallisation mechanism and this work may provide a route to tailor lipid crystallisation behaviour in future.
