Applications of ultrasonics in food science - novel control of fat crystallization and structuring

Low power (< 10 W m-2) ultrasound spectroscopy has been used for many years for the characterisation of food colloids with respect to particle size distribution, adiabatic compressibility, particle solvation and dissolution, crystal nucleation and solid content. Whilst high power (>1 kW m-2) ultrasound methods are well-known to impact on fat crystallization and structuring, they have many drawbacks, causing off-flavours through product oxidation and a metallic taste probably associated with sonotrode wear. Furthermore, process development with power ultrasound is hit and miss, applications being largely empirical and poorly understood. We have recently shown that well-controlled and understood crystal nucleation control can be obtained using well-defined low power, quasi-continuous ultrasound and acoustical pressure fields, opening up a new field of application in food processing for ultrasonics.