The effects of different extraction methods on the structure, physicochemical, and functional characteristics of dietary fiber from Rape Bee Pollen

Dietary fiber has important physiological functions, and its effects vary with sources and extraction methods. However, research on pollen-derived fiber is still limited. In our study, three extraction methods—enzymatic extraction, ultrasonic-assisted enzymatic extraction, and microwave-assisted enzymatic extraction—were employed to obtain dietary fiber from rape bee pollen. The resulting total dietary fiber (TDF), namely enzyme-extracted dietary fiber (EDF), ultrasound-assisted enzyme-extracted dietary fiber (UDF), and microwave-assisted enzyme-extracted dietary fiber (MDF), were systematically compared in terms of their structural, physicochemical, and functional properties. The results revealed a clear trade-off: enzymatic extraction produced the highest TDF yield (48.9%), followed by UDF (42.3%) and MDF (39.7%), whereas the physical-enzymatic methods yielded fibers (UDF and MDF) with superior functional properties. MDF contained a higher arabinose content (36.64%) than EDF (30.76%) and UDF (31.98%). Compared with EDF, both UDF and MDF exhibited looser, more porous structures. Consequently, MDF showed the highest oil-holding capacity (5.20 g/g) and glucose adsorption capacity (5.72 mmol/g at a glucose concentration of 100 mmol/L), UDF exhibited enhanced water-holding capacity (3.05 g/g), and the strongest DPPH radical scavenging capacity. In conclusion, physical field-assisted enzymatic extraction—especially microwave-assisted enzymatic extraction—effectively modulates the structure of pollen dietary fiber and enhances its functional properties. These findings provide a theoretical basis for the efficient preparation and utilization of rape bee pollen dietary fiber, highlighting its potential as a functional ingredient in food products. • Enzymatic extraction achieves the highest dietary fiber yield, whereas physical-assisted methods produce fibers with superior functional properties. • Extraction methods affected monosaccharide composition, structural and functional properties of TDF. • MDF displayed excellent water and oil holding capacity, and glucose adsorption capacity. • UDF exhibited highest water holding capacity and excellent DPPH radical scavenging activity.