Ultrasonic emulsification: An overview on the preparation of different emulsifiers-stabilized emulsions

Emulsion systems are widely applied in food industry. Several methods have been used for emulsion preparation. Among these methods, high intensity ultrasound (HIU) has attracted much attention because it is considered as an eco-friendly and cost-effective method. The acoustic cavitation phenomenon induced by HIU devices can boost the disruption of oil droplets, facilitating the formation of stable emulsions. This review briefly discusses the major differences between different emulsification devices and the mechanism of ultrasound emulsification process. In addition, emulsion preparation using different emulsifiers such as proteins, polysaccharides and surfactants has been covered in this review. The challenges and future trends of ultrasonic emulsification have also been discussed. HIU could be used to improve the emulsifying properties of food emulsifiers such as proteins and polysaccharides and enhance the stability of their emulsions. Protein-polysaccharide complex stabilized emulsions produced by HIU showed better stability against environmental stresses than the emulsions stabilized by individual components. Moreover, several studies showed that HIU homogenizers were more energy efficient than high pressure homogenizers and microfluidizers. However, research cooperation between academic institutes and food companies is recommended to develop effective large scale ultrasonic devices.