Difference in Physicochemical Property of β-Glucan from Barley Flour and Bran

Abstract

Two kinds of β-glucan were extracted from barley flour and bran, with the purity of 75.3% and 76.2% respectively. Molecular size characterization was caarried out with high performance size exclusion chromatograhy combined with a multi-angle laser light scattering and a refractive index detector (HPSEC-MALL) , the molecular weight (Mw) of β-glucan from barley flour and bran was 2.262×104,7.128×104. X-ray diffraction and thermodynamics tests indicated that all β-glucans were noncrystalline but thermostable polymers. Differential scanning of calorimetry (DSC) showed the presence of peak related with water loss, confirmed by thermogravimetric analysis (TGA), the β-glucan from barley bran had higher onset temperature (T0=49.89°C) and peak temperature (TP=197°C). In scanning electron microscope (SEM) observations, the β-glucan from barley bran showed more tight surface,which could be caused by higher molecular weight.