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.
Malt intended for use in beer brewing or elsewhere in the food industry
This method describes the fluorimetric determination of high-molecular weight β-glucans in malt.
Malt intended for use in beer brewing or elsewhere in the food industry
The method describes how to determine the β-glucans in wort or Congress wort by means of a colorimetric method.
Applicable for all (laboratory) worts
The colorimetric method may be used for the determination of high molecular weight β-glucan in wort; it is based on the photometric evaluation of a β-glucan color complex. The soluble β-glucan from barley reacts with a buffered solution, forming a color complex within 30 minutes. The absorbance of the β-glucan color complex is measured at 550 nm.
This method describes the fluorimetric determination of high-molecular weight β-glucans in laboratory worts.
Suitable for all types of (laboratory) worts
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.
Reproducible measurements for fluorescence and determination of β-glucan are possible through measurement in an automatic analysis system based on flow injection (flow-injection analysis). The apparatus is calibrated using purified barley β-glucan standard solutions.
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.