OPTIMIZED McCLEARY METHOD FOR MEASUREMENT OF TOTAL β-AMYLASE IN BARLEY AND ITS APPLICABILITY

Abstract
The McCleary method for determination of β-amylase in malt has been modified in order to allow determination of total β-amylase in barley as well as malt. A ruggedness test, performed on the modified method, demonstrated that the method is quite robust and highly reproducible. When the variables α-amylase, β-amylase and diastatic power were measured in 90 malt samples, only β-amylase was significantly correlated to diastatic power (r2 = 0.85 and p < 0.0001). The same high correlation was found between total β-amylase in 20 barley samples and diastatic power in the corresponding malts. The validity of this relationship was tested by predicting diastatic power in malt from total β-amylase in barley. Predicted values correlated highly to measured values (r2 = 0.95). In breeding material a positive relationship was found between total β-amylase in barley and protein content. This relationship must be considered when evaluating new barley lines.