Extraction of chitin-glucan complex from shiitake (Lentinula edodes) fruiting bodies using natural deep eutectic solvents and its prebiotic potential.

Chitin-glucan complex (CGC) is an emerging novel prebiotic with numerous physiological activities in amelioration
of clinical manifestations. In the present work, natural deep eutectic solvent (NADES), ultrasonication, and
submerged fermentation using probiotic microorganisms were deployed for the extraction of CGC from Shiitake
fruiting bodies. CGC obtained through non-ultrasonication assisted fermentation employing Lactiplantibacillus
plantarum exhibited maximum polysaccharide yield (27.86 ± 0.82 % w/w). However, based on antioxidant
potential, NADES combination of urea: glycerol (1:1 M ratio) was selected for further characterization. The
rheological behavior of CGC under optimized conditions showed shear thinning property in both 0.1 M NaCl and
salt-free solution. FTIR, 1H-(1D), and 2D 1H–1H Homonuclear NMR spectra displayed distinctive patterns
associated with β-glycosidic linkage and β-D-glucopyranose sugar moiety. XRD profiles of CGC exhibited characteristic
peaks at 2θ = 23◦, 25◦, and 28◦ with corresponding hkl values of (220), (101), and (130) lattice planes,
respectively. Enhanced radical scavenging activities were noticed due to the triple helical structure and anionic
nature of CGC. CGC exhibited potential prebiotic activity (prebiotic score 118–134 %) and short chain fatty acids
liberation (maximum 9.99 ± 0.41 mM by Lactobacillus delbrueckii). Simulated static in-vitro digestion demonstrated
that CGC withstands acidic environment of gastric phase, which indicated its suitability for use as a
prebiotic in nutraceutical-enriched food products.