FOOD SCIENCE ›› 2021, Vol. 42 ›› Issue (10): 52-57.doi: 10.7506/spkx1002-6630-20210118-187

• Food Chemistry • Previous Articles     Next Articles

Extraction, Purification and Structure Analysis of Soluble Acidic Polysaccharides from Soybean Dregs

WANG Siqi, HU Yanbo, ZHAI Liyuan, SHI Zenghui, ZHAO Jun   

  1. (College of Food Science and Engineering, Changchun University, Changchun 130022, China)
  • Online:2021-05-25 Published:2021-06-02

Abstract: The crude polysaccharide extracted from soybean dregs was purified and fractionated into two soluble acid polysaccharide fractions with uniform charge, SSPS-A1 and SSPS-A2. SSPS-A1 was further subjected to gel filtration chromatography, yielding a homogenous polysaccharide with uniform charge, SSPS-A1-c. Its molecular mass and monosaccharide composition were measured, and its structure was analyzed by infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy. The results showed that SSPS-A1-c had a molecular mass of 31.6 kDa, mainly composed of galacturonic acid (GalA), galactose (Gal) and arabinose (Ara) with a molar ratio of 17.3:44.9:19.1 together with lesser amounts of rhamnose (Rha), glucose (Glc) and xylose (Xyl). IR spectroscopy analysis showed that SSPS-A1-c had the characteristic absorption peaks of acidic polysaccharides such as O–H, C–H and C=O and it may be methylated or acetylated to a certain extent. NMR results showed that SSPS-A1-c had chemical shifts of α-1,5-Araf, α-t-Araf and β-t-Galp, which was speculated to contain arabinogalactan (AG)-type pectin domain. Besides, it also exhibited chemical shift of α-1,4-GalpA, which was inferred to contain the homogalacturonan (HG)-type pectin domain. The NMR results were consistent with the monosaccharide composition and infrared analysis results. The research results will provide a theoretical basis for the application of soluble acidic polysaccharides from soybean dregs, and will be of great significance to the comprehensive development and utilization of soybean dregs.

Key words: soybean okara; soluble acid sugar; separation and purification; structure analysis

CLC Number: