Hydrolysis of β-glucan

The acid and enzymatic hydrolyses of oat β-glucan were compared for commercial oat β-glucan and β-glucan isolated from oat grain and oat bran. The resulting mono- and oligosaccharides were analysed by high-performance anion-exchange chromatography, combined with pulsed amperometric detection. The acid hydrolysis was studied with HCl, TFA and H2SO4 at two concentrations, with three durations of hydrolysis and at three temperatures.Under the mildest acid conditions (37 °C and pH 1, corresponding to those in the human stomach) no degradation of β-glucan was observed with HCl over a 12 h period. At 120 °C, total hydrolysis to glucose occurred with high-concentration acids. Total recovery was also achieved with lichenase hydrolysis. Hydrolysis, with lichenase and β-glucosidase together, produced glucose, which was analysed spectrophotometrically according to the AOAC 995.16 method. Since the results with the original method were not satisfactory, the method was further modified to determine the best conditions for samples with high β-glucan content and poor solubility.