Ultrasound-assisted extraction of lipids as food components: Mechanism, solvent, feedstock, quality evaluation and coupled technologies – A review

Lipids are increasingly attractive in the food industry, resulting in an increasing demand for lipids from edible and non-edible sources. Conventional solvent extraction has drawbacks of low efficiency, long time, and large solvent consumption, and it can negatively impact the lipid quality such as oxidation due to long extraction time and high temperature. Ultrasound-assisted extraction (UAE) can overcome these shortcomings and has received more attention. Whereas, a comprehensive evaluation of ultrasound-assisted lipid extraction is not yet available. This review focuses on an in-depth understanding of ultrasound-assisted lipid extraction, including mechanisms, solvent systems, feedstocks, the impacts of ultrasound on lipid quality (constituents, antioxidant, stability and antibacterial properties), and ultrasound coupled extraction technologies (enzyme, hydrodistillation, microwave and supercritical fluid). The mechanisms of UAE involve cavitation effects, which can destroy cells and enhance mass transfer. Solvent plays a vital role in the extraction process. Different levels of ultrasonic energy release capabilities may occur in various solvents. UAE has good compatibility and is suitable for the treatment of materials from various origins including plants, microalgae, animals and fungi. UAE can improve extraction efficiency and lipid quality. Ultrasonic treatment has a positive influence on the composition, anti-oxidation, stability and antimicrobial properties. Ultrasonic coupled extraction technologies normally extract lipids more efficiently due to the synergistic effect. Therefore, according to current literature, UAE can occupy a very important position in the lipid extraction industry.