Enhancing Gel Properties of Pork Myofibrillar Protein with Mung Bean Skin Insoluble Dietary Fibres and Its Application as a Fat Replacer in Low-Fat Mayonnaise

Abstract This study aimed to explore the functional application of modified insoluble dietary fibre (MIDF) in enhancing the gel properties of meat-based products and to evaluate the potential of MIDF-MP composite gels as promising fat replacers in mayonnaise and other food formulations. Specifically, the effects of various concentrations (0%–5%) of MIDF derived from mung bean hulls on the gel properties of pork myofibrillar protein (MP) were investigated, and the application of these composite gels as fat replacers in low-fat mayonnaise was further examined. Results indicated that a high MIDF concentration (5%) effectively enhanced the MP gel network structure, with significant increment in WHC (82.09%), gel strength (25.94 N·mm), and storage modulus (G’). The LF-NMR results demonstrated that MIDF promoted the transformation of free water into immobilized water within the gel matrix. Infrared spectroscopy revealed that MIDF incorporation facilitated a conformational transition from α-helix to β-sheet within MP. This structural rearrangement strengthens intermolecular interactions, enabling the formation of a continuous three-dimensional gel network that resists mechanical deformation and immobilizes water molecules. Further, the composite gel was utilized as the fat replacer to formulate low-fat mayonnaise, and the sample containing 3% MIDF exhibited comparable rheological and sensory properties to full-fat mayonnaise.