Evaluation of a general method for measurement of (1→3), (1→4)‐β‐Glucans

A method for determination of total (1→3), (1→4)‐β‐D‐glucans, involving the reduction of all endogenous reducing sugars in the sample with sodium borohydride, hydrolysis of the β‐glucan with a specific (1→3), (1→4)‐β‐glucanase (EC 3.2.1.73)and measurement of the reducing sugars produced by reaction with p‐hydroxybenzoic acid hydrazide (PAHBAH), was shown to be suitable for application to both solid (ground grain) and liquid (beer) samples. The colour response of PAHBAH with the major oligosaccharides produced by the β‐glucanase was determined. Calibration of the method against a β‐glucan standard has advantages over methods that assume complete hydrolysis and involve calibration with glucose. The method has high precision and accuracy. The reduction step allows the method to be applied directly to beer samples without the prior isolation of the β‐glucan. Beer samples were found to contain total β‐glucan concentrations between 0.15 and 0.73 g litre −1 .