Ultrasound-induced changes in the structure and functionality of starch and protein

Ultrasound technology is an emerging sustainable processing method that modifies the composition, structure, and functional properties of starch and protein in plant food through its chemical and thermo-mechanical effects. The cavitation effect generated by ultrasound disrupts starch granules and affects molecular reorganisation, thereby enhancing swelling power, solubility, thermal stability, pasting viscosity, gelation and retrogradation. However, excessive ultrasound treatment can damage granules and degrade crystalline regions, diminishing relative structures and properties. Similarly, ultrasound alters protein structures by breaking molecular interactions, partially unfolding peptide chains and modulating aggregation behaviour. While cavitation improves protein solubility, surface hydrophobicity, emulsification, foaming and gelation properties, excessive ultrasound exposure may induce oxidative modifications that reduce protein functionality. Furthermore, ultrasound affects starch–protein interactions by either enhancing or reducing glycation reactions, and influences solubility, thermal stability, foaming capacity, gel formation, and textural properties. The manuscript provides a critical analysis of the current knowledge on the dual effects of ultrasonication on isolated starch and protein or in-situ in food systems, facilitating the development of improved starch-protein ingredients tailored for food industry applications.