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

Abstract

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.

Influence of gas addition on crystallisation behaviour of lactose from supersaturated solution

“…The calculated ultrasound intensity was 0.045 Wcm -2 . This low power ultrasound at 205 kHz frequency will not cause the cavitation and is supposed to provide only the mechanical effect to generate the gas bubbles from the dissolved gas in the solution (Leong et al, 2011;Povey, 2017).…”

“…The more pronounced effect on the reduction of particle size by CO2 than N2 might also be linked to lowering of surface tension of crystallising liquid by the dissolved gas. It was pointed out that the more soluble the gas the more it reduces surface tension and the higher the nucleation rate (Povey, 2017). This reduction of crystal size could also be attributed as synergistic effect of ultrasound and gas bubble.…”

Acoustic characterisation of pH dependant reversible micellar casein aggregation

“…Turbidity measurements are limited by cost, measurement repeatability and the fragility of sensors [44][45][46]. Acoustic methods are repeatable, non-destructive, non-invasive and can measure concentrated and polydisperse systems [47][48][49]. Ultrasonic techniques can reliably size particles between 10 nm and 1 mm [50].…”

Synthesis, physicochemical properties, and health aspects of structured lipids: A review

“…Applying shear also has a significant effect on fat crystallization through various manners, such as accelerating fat nucleation, growth, and polymorphic transition, and inducing orientation of fat crystal networks (Tran & Rousseau, 2016). Furthermore, other processing techniques including high-intensity ultrasound (Kadamne, Ifeduba, Akoh, & Martini, 2017;Povey, 2017;Wagh, Birkin, & Martini, 2016) and high pressure processing (Zulkurnain, Maleky, & Balasubramaniam, 2016) have also been found to affect fat crystallization behavior and physical properties, but further research is still needed before these novel methods can be applied in an industrial setting. The crystallization behavior of SLs may also be altered by adding minor components.…”