Structural, physicochemical, and emulsifying properties of insoluble Pueraria fiber: Effects of enzymatic hydrolysis combined with high-pressure processing

Agricultural byproduct-derived dietary fiber has increasingly attracted attention as a novel emulsion stabilizer. This study aimed to investigate the effects of homogenization, cellulase hydrolysis, and sequential hydrolysis-homogenization on the structure and emulsifying properties of insoluble Pueraria fiber (IPF). Findings revealed that neither cellulase hydrolysis nor homogenization altered the functional groups and crystalline structure of IPF. Unhydrolyzed IPF exhibited abundant branched chains and high water-holding capacity. In contrast, hydrolyzed IPF exhibited a porous structure, and subsequent homogenization increased surface electronegativity (from –17.07 to –28.63 mV) and oil holding capacity. Low-oil-phase ( Φ = 0.1) emulsions prepared with unhydrolyzed IPF exhibited better stability. Hydrolysis increased droplet size, whereas homogenization reduced particle size across all IPF emulsions. The unhydrolyzed IPF emulsion exhibited a minimum particle size of 15.38 μm at 60 MPa (Emul 0-60 ). At Φ = 0.4, unhydrolyzed IPF failed to form a stable emulsion, whereas hydrolyzed IPF successfully stabilized the system. Moreover, increasing homogenization pressure enhanced the emulsifying performance of hydrolyzed IPF (peaking at 40 MPa). In conclusion, unhydrolyzed IPF exhibited superior performance in low-oil emulsions, whereas combining cellulase hydrolysis with IPF homogenization enabled more stable middle-oil-phase emulsions, thereby expanding its application in the food and pharmaceutical fields. • Insoluble Pueraria fiber (IPF) can stabilize Pickering emulsions as a new material. • Cellulase-homogenization treatment effectively modified IPF. • Hydrolysis led to porous structure and enhanced crystallinity index of IPF. • Further homogenization after cellulase treatment enhanced IPF emulsification. • The stabilization mechanism of IPF-based Pickering emulsions was clarified.