ENZYMATIC DETERMINATION OF 1,3:1,4‐β‐GLUCANS IN BARLEY GRAIN AND OTHER CEREALS †

A direct and specific enzymatic method is described for the determination of 1,3:1,4‐β‐glucans in barley grain and other cereals. In the procedure, purified, amylase‐free, bacterial 1,3:1,4‐β‐glucan hydrolase is used to depolymerize the 1,3:1,4‐β‐glucan in autoclaved and ethanol‐extracted flour prepared from whole grain. The liberated oligoglucosides are extracted with 80% (vol/vol) ethanol and, following acid hydrolysis, measured by the glucose oxidase method. The method can be used to measure total β‐glucan and β‐glucan in 65°C water‐soluble and water‐insoluble fractions of cereal grains. The procedure has been applied to barley grains allowed to develop under controlled environmental conditions and to a series of barleys of different geographical origins. The results for Canadian cultivars are compared with estimates based on viscometric data for the same samples. The 1,3:1,4‐β‐glucan content of a number of other cereals has also been measured.