Extraction, Separation And Purification, Properties Of Water-solubleβ-glucan From Highland Barley Bran

This article was to study about extraction, separation and purification of water-soluble β-glucan from Highland barley bran. The following conclusions were obtained:(1) Microwave-assisted extraction process was determined as the best extraction process for the highland barley bran β-glucan. The extraction rate was up to4.66%.(2) The optimal process for the removal of starch:enzyme dosage2U/mL feed solution, pH6.4, temperature90℃, reaction time40min; the optimum process for the removal of protein: trypsin-isoelectric point method, the protein removal rate was60.23%while the polysaccharide retention rate was95.20%; best decolorization technology was dynamic decoloration of XAD-7, decolorization rate was up to58.24%.(3) In the DEAE-52cellulose separation process, a big elution peak without protein can be obtained while deionized water elution. And a small protein-containing elution elution peak was obtained when it was eluted with0.05mol/L sodium chloride solution. Only one component was got through Sephadex G-200column chromatography separation.(4) Purified β-glucan product contained no starch, phenol, protein. Purity was determined as99.7%by Congo red method. Fourier transform infrared spectroscopy and polarimetry analysis showed the glucan obtained from highland barley bran was β-configuration, and did not contain a-D-glucan. The purified β-glucan had a number average molecular weight (Mn) as589,545, weight average molecular weight (Mw) as769,046, and the peak molecular weight (Mp) of802,319.(5) The main component of both the purified barley bran β-glucan hydrolyzates and the crude barley bran β-glucan hydrolyzate were glucose. HPLC analysis of the purified barley bran P-glucan hydrolyzate contained only glucose; the crude barley bran β-glucan hydrolyzate may also contain trace amounts of mannose, xylose and arabinose.(6) Highland barley bran source β-glucan had scavenging ability on DPPH,·OH, H2O2, superoxide radicals. The viscosity of β-glucan increased with the concentration increasing while decreased with the temperature increasing. Viscosity of β-glucan solution was relatively stable in the range of pH7～10, but decreased in lower pH.