The ultrasonic-assisted alkali extraction of Typha domingensis stem polysaccharide (TDSPs) was studied using the response surface methodology. The optimal parameters of TDSPs with maximum yields (12.24± 0.08%) were as follows: extraction time 40 min, NaOH concentration 1.5 M and the ratio of water to raw material 25mL/g. The experimental purity of TDSPs was 86.01 ± 0.02. Mineral elements were determined by ICP-AES. The gel permeation chromatography results indicated that TDSPs was a polysaccharide polymer with two peaks with molecular weights of 3182.6 Da (P1) and 3,076,900 Da (P2). The TDSPs consisted of arabinose, rhamnose, galactose, xylose, glucose, mannose, and fructose. The results of NMR and FT-IR spectra represented the presence of β-configurations in TDSPs. Moreover, the TDSPs improved the stimulating effect on the growth of selective probiotic bacteria and showed relatively good antioxidant activity. Therefore, due to its good prebiotic and antioxidant activity, TDSPs could be exploited as a novel natural component in functional food industries.
Keywords: Antioxidant; Polysaccharides; Prebiotic; Structural characterization.
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