Modified Rice Bran Dietary Fiber-Based Pre-Emulsion as a Fat Replacer: Modulating Physicochemical and Sensory...

Polysaccharide-based pre-emulsions offer a promising strategy for reducing saturated fat in emulsified meat products. In this study, a pre-emulsion stabilized by rice bran dietary fiber modified with alkaline hydrogen peroxide (MRF) was used to replace pork back fat in emulsified meat gels. Four model systems were prepared, varying in fat content (20% and 50%) and chopping intensity (low vs. high). MRF pre-emulsion significantly reduced fat globule size (e.g., D_[4,3] decreased by 18-34%, D_[3,2] by up to 83%) and improved shear stability, as reflected in the weaker frequency dependence of the storage modulus (G'). In high-chopping systems, MRF substitution increased gel elasticity but lowered hardness (by 25-30%), chewiness, and shear force (by 20-25%). Low-field NMR analysis revealed a partial shift from immobilized to free water, which raised cooking loss by 2-4 percentage points while enhancing perceived juiciness. Color measurements indicated that MRF effectively offset the loss of lightness typically associated with fat reduction. Both quantitative descriptive analysis (QDA) and temporal dominance of sensations (TDS) confirmed that MRF-substituted samples showed a markedly lower dominance of fatty sensation during the late oral processing stage (30-40% reduction in dominance rate), whereas the overall dynamic sensory profile remained similar to that of full-fat controls. Collectively, these results demonstrate that MRF, as a functional polysaccharide, stabilizes the system through hydration-induced swelling, hydrogen bonding with myofibrillar proteins, and the formation of a composite interfacial film around fat globules. These mechanisms enhance emulsion stability and successfully mimic the oral textural properties of animal fat, supporting the use of MRF as an effective polysaccharide-based fat replacer in reduced-fat meat products.