Structural Properties of a Heteropolysaccharide Released from Isaria cicadae Miq. Solid-State Fermented Wheat Bran

Abstract

The work aimed to improve the extraction efficiency of wheat bran polysaccharide by solid-state fermentation using the bioactive fungus Isaria cicadae Miq. and identify the structural properties of fermented wheat bran polysaccharide (IC-FWBP). The polysaccharide fraction of IC-FWBP was isolated with an extraction yield of 2.88% and an average molecular weight of 3.31 × 106 Da. The IC-FWBP was comprised of mannose, glucose, and galactose. The methylation, nuclear magnetic resonance (NMR), and Congo red analysis results suggested that IC-FWBP contained glycosidic linkages of T-β-D-Glcf, 1→2-α-D-Manp, 1→5,6-β-D-Galf, 1→2,3,4-α-D-Galp and 1→2,3,4-β-D-Manp, with triple-helix conformations. The morphological observation showed that IC-FWBP was composed of rod-like and spherical particles. These investigations on the structural properties of IC-FWBP will be beneficial to further research on the functional properties of wheat bran polysaccharides.