IEEE International Ultrasonics Symposium location:Dresden date:7-10 October 2012
In the production of fat containing food products,
insight in the crystallization behaviour of fats is of utmost
importance to obtain the desired product functionality and
product quality. The aim of this research is to study the potential
of advanced ultrasonic techniques to monitor fat crystallization.
For reasons of sensitivity and signal quality during the entire
process, we concentrate on shear wave reflectivity measurements
at the interface between a fat sample and a plexiglass delay line.
Preliminary experiments show that interesting evolutions can be
observed in the experimentally obtained reflection coefficient during
the crystallization process of cocoa butter, and we conjecture
that the observed features can be linked to particular phases in
the process. Additional measurements have been performed to
check the influence of sample properties and of the experimental
set-up, such as the viscosity or thickness of the cocoa butter layer.
It is found that the thickness of the layer influences the reflection
coefficient up to a frequency dependent limiting thickness value.
In order to eliminate this influence and avoid its contamination
in the analysis of the crystallization phases, it is required to use
sufficiently thick fat layers. To support the experiments, a shear
reflectivity simulation model is proposed, which is coupled to the
evolution of sample parameters.