Comparative Assessment of β-glucan Composition and Structural Characterization in Wild and Commercial Enoki Mushrooms, Flammulina velutipes

From the paper

Abstract

This study investigated the β-glucan content and structure in an indigenous Enoki mushroom compared with a European commercial strain. Both Enoki types belonged to the same species, Flammulina velutipes, and grew on the same substrate. An enzymatic β-glucan assay to measure β-glucans showed higher β-glucan levels (20.10% dw vs. 15.82% dw) and lower α-glucan levels (0.5% dw vs. 3.18% dw) in fruiting bodies of the indigenous strain compared to the commercial strain (p ≤ 0.05). However, both strains demonstrated similar levels of β-glucans (22.00-23.00% dw) in their fruiting bodies-derived hot water extracts (HWEs), whereas the commercial Enoki β-glucans exhibited better solubility. High-performance liquid chromatography quantified total glucans of the HWEs in a range similar to that obtained from the enzymatic assay. Fourier-transform infrared spectroscopy and proton nuclear magnetic resonance confirmed similar primary structure of β-glycosidic bonds in the purified polysaccharides of both strains. However, α-configuration was confirmed only for the commercial Enoki. Atomic force microscopy also revealed that the commercial Enoki β-glucans were shorter, narrower and more branched in the spatial structure. These findings demonstrated the usefulness of commercial Enoki β-glucans in the food or health industry, while the indigenous Enoki can have value as a pleasant high β-glucan food.