Superiority of simultaneous over sequential and individual microwave-ultrasonication: synergy-driven reconfiguration of citrus fibers structure and functional properties

Microwave (MW) and ultrasonication (US) synergistic treatment was applied to modify citrus fiber. Simultaneous processing (UMCF) integrated high-energy of MW and cavitation of US, outperforming individual or sequential treatments ( P < 0.05 ). It significantly increased soluble dietary fiber (SDF) and decreased insoluble fiber (IDF) ( P < 0.05 ). Spectroscopy and microscopy revealed hydrogen bond disruption, increased hydroxyl groups, and a porous, flake-like structure. UMCF60 enhanced solubility, apparent viscosity, water-holding (WHC), oil-binding (OBC), swelling capacity (WSC), emulsifying activity (EAI), and emulsion stability (ESI) by 52.87%, 284.04%, 52.97%, 74.05%, 390.82%, 148.24%, and 70.04%, respectively, and reduced median particle size by 21.59%. Principal component analysis and heatmaps confirmed the superior properties of UMCF60. Thus, the simultaneous MW-US treatment developed in this work presents an effective strategy for modifying citrus fiber into a high-functional ingredient.