This method describes how to determine the β-glucan content in barley.
High molecular weight β-glucan includes (1−3)(1−4)-β-D-glucan.
The β-glucan content of barley influences the modification processes which occur during malting and consequently affects the quality of the finished malt.
The β-glucan content of barley intended for use in beer production should be known.
The fluorochrome Calcofluor forms a complex with high molecular weight β-glucans (molecular weight greater than 5 kDa). Complex formation results in an increase in fluorescence; however, this fluorescence is extremely unstable due to photochemical degradation.
Through measurement in an automatic analysis system based on flow injection (flow-injection analysis, fig. 1), reproducible measurements for fluorescence and determination of β-glucan are possible. For barley analysis, it is necessary to use a short acid hydrolysis procedure to bring insoluble β-glucan into solution. The apparatus is calibrated using purified barley β-glucan standards.