Extraction, purification, structural characterization of Anemarrhena asphodeloides polysaccharide and its effect on gelatinization and digestion of wheat starch

Pressurized water extraction (PWE) of the polysaccharides from Anemarrhena asphodeloides rhizomes was optimized by the response surface method (RSM). The high yield of 34.82 ± 0.38% was gained under the optimal conditions of material to liquid ratio 42 mL/g, pressure 6.4 MPa, extraction temperature 51 °C, and extraction time 15.3 min. An Anemarrhena asphodeloides rhizome polysaccharide (AARP) was obtained after purifying by D4006 macroporous resin and Sephadex G-100 column. High-performance liquid chromatography (HPLC) analysis showed that AARP with the molecular weight of 5100 Da consisted of four monosaccharides including mannose, glucose, galactose, and arabinose. 1D and 2D NMR analyses confirmed that the backbone of AARP was comprised of →4)-β-D-Manp-(1→, →4)-β-D-Glcp-(1→, β-L-Araf-(1→, →2)-β-D-Manp-(1→, and →3)-α-D-Galp-(1→ residues. In addition, AARP exhibited the property of inhibiting the pasting and in vitro digestion of wheat starch. These findings laid the foundations for AARP as an additive in regulating starch foods.