Extraction of ß-Glucan from Oat Bran in Laboratory Scale

Effects of various enzymes and extraction conditions on yield and molecular weight of ß-glucans extracted from two batches of commercial oat bran produced in Sweden are reported. Hot-water extraction with a thermostable a-amylase resulted in an extraction yield of ˜76% of the ß-glucans, while the high peak molecular weight was maintained (1.6 × 106). A subsequent protein hydrolysis significantly reduced the peak molecular weight of ß-glucans (by pancreatin to 908 × 103and by papain to 56 × 103). These results suggest that the protein hydrolyzing enzymes may not be pure enough for purifying ß-glucans. The isolation scheme consisted of removal of lipids with ethanol extraction, enzymatic digestion of starch with a-amylase, enzymatic digestion of protein using protease, centrifugation to remove insoluble material, removal of low molecular weight components using dialysis, precipitation of ß-glucans with ethanol, and air-drying.