Difference in physicochemical property of β-glucan from barley flour and bran

摘要

Two kinds of P-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 (M_w) of P-glucan from barley flour and bran was 2.262X10~4,7.128X10~4. X-ray diffraction and thermodynamics tests indicated that all p-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 P-glucan from barley bran had higher onset temperature(T_0 = 49.89°C) and peak temperature(T+p = 197°C). In scanning electron microscope (SEM) observations, the P-glucan from barley bran showed more tight surface,which could be caused by higher molecular weight.