Ultrasound modified polysaccharides: A review of structure, physicochemical properties, biological activities and food applications

Background: Polysaccharides as biologically essential macromolecules widely exist in plants, animals, and microorganisms. In food industries, they are often used to change physicochemical and textural properties of food products. Ultrasound processing is increasingly used in the modifications of polysaccharide functionalities. Cavitation induced by ultrasound produces high shear force and temperature, leading to the degradation of polysaccharides. This method can improve physicochemical properties and biological activities of polysaccharides for food applications. Scope and Approach: Recent advances in ultrasound processing on extraction, structures, physicochemical properties, and biological activities of diverse polysaccharides are summarized. Mechanisms of action responsible for the ultrasound effects are discussed. Food applications of polysaccharides affected by ultrasound processing are also reviewed. Research gaps in ultrasound-related studies and applications of polysaccharides are identified. Key Findings and Conclusions: Ultrasound-assisted extraction increased yield and reduced extraction time of polysaccharides from different sources. Structure of polysaccharides was changed after ultrasound processing, leading to the modifications of their physicochemical and biological properties. The extents of these changes were influenced by ultrasound frequency and intensity, processing time, solvent temperature, and polysaccharide source and composition. The ultrasound processing involving polysaccharides has been applied in different areas such as fabricating food emulsions and nanoparticles. Overall, ultrasound technology has great potential to be used in food industries for improved functionalities of polysaccharides. © 2020 Elsevier Ltd