Application of acoustic models for polydisperse emulsion characterization using ultrasonic spectroscopy in the long wavelength regime

•Ultrasonic spectroscopy for characterization of water-in-sunflower oil emulsions is used.•Ultrasonic wave propagation theories in the heterogeneous systems are presented and discussed.•A measurement cell and signal processing method to evaluate the acoustic properties are developed.•Methodology employed in sizing the particle size distribution of emulsions for diluted or moderate concentrations.