Structural features, physicochemical properties and functional activities of soluble dietary fiber from Hericium erinaceus mycelium and fruiting body via ultrasound-assisted compound enzymatic extraction

Abstract

The influence of intrinsic cell wall differences between Hericium erinaceus mycelium and fruiting body on soluble dietary fiber (SDF) properties under a unified extraction system remains unelucidated, hindering targeted use of these SDF sources. Here, SDF from mycelium (M-SDF) and fruiting body (F-SDF) of H. erinaceus were prepared under strictly identical ultrasound-assisted compound enzymatic extraction (UAEE), with tissue origin as the sole variable. Structural analysis revealed a shared backbone but distinct architecture: M-SDF was pectin-rich (galacturonic acid 67.9 g/kg) with higher molecular weight (82.32 kDa), higher crystallinity, and an intact three-dimensional porous network. F-SDF was glucan-dominant (glucose 515.6 g/kg) with lower molecular weight (59.27 kDa), amorphous structure, and uniform honeycomb micropores. These structural features directly governed functional divergence. M-SDF showed high water solubility (83.7%), weak-gel rheology, and superior antioxidant and cholesterol adsorption, positioning it for thermally stable, lipid-lowering foods. F-SDF exhibited excellent water/oil holding, glucose adsorption, α-amylase inhibition, and nitrite scavenging, ideal for glycemic control and gastric detoxification. This study provided the first systematic structure-function model for H. erinaceus SDF from different tissue origins, offering a theoretical and technological foundation for targeted preparation and differentiated industrial utilization of mycelial and fruiting body SDFs.