This SpringerBrief provides an overview of ultrasonic emulsification and an update on recent advances in developing stable emulsions for the creation of novel drugs and functional foods, with a focus on bioactive delivery in these products. Emulsification is the process of combining two or more immiscible liquids to form a semi-stable mixture. These two liquids generally consist of an organic (oil) phase and an aqueous (water) phase that is stabilized by the addition of an emulsifier. Most common emulsions are of the oil-in-water (O/W) type, but can also be of water-in-oil (W/O) or even multiple emulsion types (i.e. double emulsions) in the form of water-in-oil-in-water (W/O/W) or oil-in-water-in-oil (O/W/O) phases. The formation of an emulsion requires input of energy to distribute the disperse phase in the continuous phase in small-sized droplets that are able to resist instability. There is great interest in the use of ultrasound to produce emulsions, as it is able to do so relatively efficiently and effectively compared to existing techniques such as rotor stator, high-pressure homogenization and microfluidization. The interaction of ultrasound with the hydrocolloids and biopolymers that are often used to stabilize emulsions can offer advantages such as improved stability or greater control of formed droplet size distributions.

As nanomaterials and their end products occupy the pinnacle position of consumer markets, it becomes vital to analyze their generation processes. One of the green chemistry principles underlines the need for unusual energy sources to generate them. Utilizing the extreme energy from the collapse of cavitation bubbles, generated by either ultrasound or hydrodynamic forces, for the generation of nanomaterials is a merit to consider in this "Green Chemical Processing Era." A wide range of nanomaterials have been developed in the past decade using cavitation or coupling cavitation with other techniques such as microwave, photochemistry, and electrochemistry, resulting in nanomaterials with unique morphologies, reduced size, narrow size distribution, and innumerous advantages. While a few currently available books deal with the fundamental aspects of cavitation and sonochemistry, this book is devoted specifically to the technologically important nanomaterials obtained by cavitation.