Most reported polysaccharides from Poria cocos (PCPs) in traditional Chinese medicine decoctions were water-soluble heteropolysaccharides while the water-insoluble PCPs were scarcely researched due to the poor water-solubility. In this study, a water-insoluble polysaccharide with high yield of 59%, and high purity with a glucan content of 98.8%, was isolated by diluted sodium hydroxide at low temperature and coded as PCPA. The chemical structure of PCPA was identified as a liner β-glucan with 1,3-linked glycosidic bond by the fourier infrared spectrum (FT-IR), ion chromatography (ICP), gas chromatography and mass spectrometry (GC-MS), and nuclear magnetic resonance (NMR) measurements. Importantly, PCPA was successfully used to construct hydrogels (PCPA-Gs) with good thermal stability, water retention ability and swelling property through simple physical cross-linking, due to the abundance of hydroxyl groups on glucan chains. Moreover, the rheology analysis of PCPA-Gs showed a rapid transition between gel and sol as well as the shear-thinning property. The hydrogel developed in this study holds promise for applications in the food, pharmaceutical, and cosmetic fields.

polysaccharide, polysaccharides, Rheology, Poria cocos, hydrogel

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
	bDGlcp	103.51	73.34	86.65	68.88	76.80	61.35


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
	bDGlcp	4.52	3.27	3.47	3.22	3.25	3.36-3.41


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
	bDGlcp	103.51/4.52	73.34/3.27	86.65/3.47	68.88/3.22	76.80/3.25	61.35/3.36-3.41

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

*O[C@@H]1[C@@H](O)[C@H](*)O[C@H](CO)[C@H]1O

162.141 g/mol (C₆H₁₀R₂O₅, R = next and previous repeats, not counted in mol weight)