This method describes the photometric determination of β-glucan content of malt.
During the malting process, endo-β-glucanases are of importance chiefly with respect to the process of modification, throughout which the cell walls of the barley endosperm undergo degradation. For the most part, these enzymes are produced, as is the case with α-amylase and proteinases, during the germination process. Over the course of mashing, further degradation takes place, this time, the water-soluble β-glucan gums and hemicelluloses are degraded through the action of the endo-β-glucanases, which reduces the viscosity of the wort.
Outside of Germany today, commercial endo-β-glucanase preparations produced primarily using bacteria and molds, are utilized in beer production. Enzyme additions make employing high percentages of adjuncts in the grist less problematic, and they also improve beer filtration processes.
Determining the endo-β-glucanase activity in malt is especially relevant, if difficulties are experienced during production processes. For commercial enzyme preparations, knowledge of their activity is requisite for employing them correctly and appraising their effects. Under references, a number of methods are listed for determining endo-β-glucanase activity.
Malt intended for use in beer brewing or elsewhere in the food industry
Using a buffer solution, malt extract is produced, and then under defined conditions the extract is incubated on an azo-barley glucan substrate. The substrate is coupled with an azo dye, which is degraded by the β-glucanase activity to form low-molecular weight fragments. After addition of the precipitating agent, these fragments stay in solution and can be spectrophotometrically determined in the supernatant after centrifugation. The absorbance in the supernatant depends directly upon the activity of the β-glucanase in the analyzed malt.