Effect of ultrasound on the preparation of resveratrol-loaded zein particles

In this study, the effects of ultrasound treatment with different frequencies and working modes on the encapsulation of resveratrol using zein were investigated. Triple-frequency simultaneous ultrasound (TFU) with 20/28/40 kHz led to the highest encapsulation efficiency (EE; 84.75% increase) and loading capacity (LC; 84.78% increase) of resveratrol, followed by dual-frequency simultaneous ultrasound (DFU) with 28/40 kHz (80.16% EE increase; 80.18% LC increase). The particle size and polydispersity index of resveratrol-loaded zein particles subjected to ultrasound treatment dramatically reduced, and the absolute value of the zeta potential increased notably. Fourier transform infrared spectroscopy analysis showed that electrostatic interactions and hydrogen bonds were strengthened after ultrasound treatment, and differential scanning calorimetry showed that ultrasound treatment improved the thermal stability of the resveratrol-loaded zein particles. Scanning electron microscopy indicated the formation of resveratrol-loaded zein particles with smooth surfaces; the particles were much smaller and had more homogeneous diameters after ultrasound treatment. Thus, ultrasound treatment is demonstrated to be an efficient method for the preparation of resveratrol-loaded zein particles to be used in functional food and beverage products.