OPTIMIZED MCCLEARY METHOD FOR MEASUREMENT OF TOTAL BETA-AMYLASE IN BARLEY AND ITS APPLICABILITY

The McCleary method for determination of beta-amylase in malt has been modified in order to allow determination of total beta-amylase in bar ley as well as malt. A ruggedness test, performed on the modified meth od, demonstrated that the method is quite robust and highly reproducib le. When the variables alpha-amylase, beta-amylase and diastatic power were measured in 90 malt samples, only beta-amylase was significantly correlated to diastatic power (r(2) = 0.85 and p < 0.0001). The same high correlation was found between total beta-amylase in 20 barley sam ples and diastatic power in the corresponding malts. The validity of t his relationship was tested by predicting diastatic power in malt from total beta-amylase in barley. Predicted values correlated highly to m easured values (r(2) = 0.95). In breeding material a positive relation ship was found between total beta-amylase in barley and protein conten t. This relationship must be considered when evaluating new barley lin es.