Process-Intensified Fabrication of Protein-Polysaccharide Conjugates: Mechanistic Foundations, Critical Advances in Reaction Control, and Future Directions for Food Applications

Process-intensified fabrication is a promising strategy for producing protein–polysaccharide conjugates with shorter processing times and improved control over conjugation selectivity, browning, and product quality. This review critically evaluates recent advances in process-intensified conjugation, focusing on reaction efficiency, browning control, structural evolution, and functional performance. Emphasis is placed on ultrasound-assisted systems, which currently dominate the field, together with microwave-assisted processing, pulsed electric fields, and selected controlled covalent routes. Evidence from recent studies shows that process intensification can accelerate conjugate formation and enhance functionality only within an optimal processing window. Moderate treatment promotes partial protein unfolding, exposure of reactive groups, improved intermolecular contact, controlled grafting, and favorable colloidal reorganization, thereby improving solubility, interfacial activity, and stability. In contrast, excessive treatment can cause reaggregation, advanced Maillard progression, browning, polysaccharide degradation, and loss of functional quality. The review highlights that intensified processing should be viewed as a process-control strategy rather than simply stronger energy input. Although ultrasound-assisted fabrication is the most widely explored approach, microwave, pulsed electric field, and hybrid methods offer promising but less-developed alternatives requiring stronger mechanistic understanding, standardized reporting, and clearer links between processing variables, structure–function relationships, and real-food performance in future research.