Effects of different ultrasonic conditions on the crystallization behavior of cocoa butter

Abstract: Sono-crystallization is a potential technology for application in cocoa butter crystallization, with its ability to increase the nucleation rate of cocoa butter and improve crystal development and arrangement. In this context, the objective of this study was to evaluate the physical properties of cocoa butter crystallized with and without ultrasound. The sample was crystallized at 25 °C (Tc), and high-intensity ultrasound (20 kHz, 3.2 mm horn, 20, 30, 40% amplitude, and 5, 10, 15, and 30 seconds) was applied. After crystallization, samples were kept at 22 °C for 24 h and analyzed for crystal microstructure with polarized light microscopy, melting behavior with a differential scanning calorimeter, rheology with an oscillaroy rheometer, hardness with a texture profile analyzer, and solid fat content (SFC) with a time-domain nuclear magnetic resonance equipment. Ultrasound treatment using different amplitudes and durations generally exhibited a slight increase in the final melting temperature, a denser oil crystalline network, and smaller crystals. The elastic value (G’) in sonicated cocoa butter samples is the highest at 40% amplitude and is higher than that of non-sonicated cocoa butter. The peak temperature (Tp) and enthalpy values of the crystallized samples increased as the amplitude and time of the ultrasound application increased. The ultrasound conditions at 40% amplitude for 5, 10, 15, and 30 seconds did not affect the SFC values of the samples, resulting in a lower SFC and higher hardness compared to the non-sonicated sample. These results show that using ultrasound in cocoa butter can effectively increase and improve crystallization speed. This study will contribute to the application of ultrasonics in crystallization optimization.