Chapter 10 - The Use of Ultrasound as an Enhancement Aid to Food Extraction

Ultrasound is particularly useful in extraction as it is able to extract high yields of target materials often at much lower temperatures when compared to normal thermal extraction processes. Extraction times are reduced, which ultimately leads to economic savings to the manufacturer. By using high-power lower-frequency ultrasound (20–40 kHz), mechanical effects are generated within the food material (in liquid form), which results in efficient mixing and homogenization. As a result this can also aid other processes, such as cleaning/sterilization and extraction of natural products. By using higher ultrasonic frequencies (300 kHz and above), more chemical and biochemical effects are observed, which could affect the food material, such as enhanced oxidation/aging or increasing kill rates of food microbes. This chapter covers a range of areas, which have employed ultrasound to process food materials, such as extraction of plants, seeds, and fruit, recycling of food waste, effects on the properties of meat and dairy products, and also includes some discussion on scale-up processes.