Determination of β-glucan content of cereals with an amperometric glucose electrode

Abstract.

A rapid method for determination of the soluble and total amount of β-glucan was investigated. β-Glucan was extracted from the samples with the modified extraction method and then incubated with lichenase and β-glucosidase. The optimum incubation parameters were determined by using pure β-glucan solutions as follows: lichenase concentration, 0.04 international units (IU) ml^–1; β-glucosidase concentration, 0.125 IU ml^–1; reaction time, 20 min; reaction temperature, 50 °C; reaction acidity, pH 6. After enzymatic incubation, free D-glucose produced by the action of enzymes on soluble and total β-glucans was measured with an amperometric glucose electrode. The linearity of the β-glucan assay was determined as 8.0% (w/w) under the considered enzymatic reaction condition. In the last part of the study, soluble and total β-glucan contents of certain samples were determined by both the improved method and the AOAC Official Method. A high correlation (R ²: 0.992) between the results of these two methods was observed.