Ultrasound-assisted multiscale structural engineering of plant proteins: mechanisms and structure–property relationships

Abstract

Plant proteins are increasingly recognized as essential ingredients for developing sustainable and health-oriented food systems; however, their broader utilization remains constrained by poor solubility, weak interfacial performance, limited gelation behavior, and suboptimal digestibility arising from their intrinsic structural organization. Among emerging non-thermal processing technologies, ultrasound-assisted processing has attracted substantial interest as a sustainable strategy for tailoring plant protein functionality through cavitation-driven physicochemical modifications. This review presents ultrasound as a multiscale structural engineering tool capable of modulating structure–property relationships in plant proteins across molecular, supramolecular, colloidal, and macroscopic scales. Acoustic cavitation generates localized shear forces, shock waves, microjets, and transient thermal–pressure gradients that disrupt hydrogen bonding, alter hydrophobic interactions, induce conformational rearrangements, and regulate aggregation–disaggregation behavior. These hierarchical structural transformations collectively govern key techno-functional and nutritional properties, including solubility, emulsification, foaming, gelation, rheology, digestibility, bioactivity, and protein–biopolymer interactions. Evidence from diverse plant protein systems, including soy, pea, lentil, chickpea, rice, hemp, mung bean, faba bean, and pumpkin seed proteins, is critically synthesized to reveal both common mechanistic trends and protein-specific responses to ultrasound treatment. Particular emphasis is placed on the concept of an optimal cavitation window, in which controlled structural unfolding enhances functionality, whereas excessive cavitation promotes reaggregation and functional deterioration. Furthermore, synergistic approaches integrating ultrasound with complementary emerging technologies are discussed to highlight future opportunities for precision structuring of plant-based foods. Overall, this review provides a comprehensive multiscale framework for understanding ultrasound-induced structural transformations and their implications for rational design of next-generation plant protein ingredients with tailored structure–property relationships.