Abstract

The interaction between sound waves and gas bubbles in liquids leads to acoustic cavitation. Extreme temperature conditions, chemical effects and strong physical forces are generated during acoustic cavitation. Both the chemical and physical effects have been used for synthesizing a variety of nanomaterials that include functional metal and polymer nanoparticles. The physical forces have long been used in preparation of food emulsions and extraction of useful compounds from plant and other materials. In recent years, many other applications of ultrasound in food and bioprocessing have been developed. In dairy industry, heat stability of dairy proteins is one of the major issues. High temperature processing is commonly used to extent the shelf life of milk and milk protein based products. The components of milk, in particular whey proteins are sensitive to heat treatment. Heat-induced gelation/aggregation of dairy proteins causes operational difficulties in dairy industry. Ultrasonic processing of whey protein solutions has been shown to increase the heat stability of these proteins. Ultrasonic encapsulation of nutrients in a protein/carbohydrate shell is another application that has been developed recently.This approach opens up the possibility of delivering nutrients using a variety of food matrix. These microspheres can also be used for the encapsulation and targeted delivery of drugs. There are a number of other food and bioprocessing applications involving ultrasound. Ultrasonic inactivation of pathogens in milk, separation of fat and crystallization of fat are some applications that could be highlighted. The presentation will provide an overview of various recent applications of ultrasound in food and bioprocessing.