SOME ASPECTS OF STABILITY OF BREWERY MALT α-AMYLASE

Abstract

The application of a method for α-amylase determination to a wide range of brewery malts has previously suggested (this Journ., 1947, 154) different heat stabilities for α- and β-amylases under kilning conditions, with the subsequent heat stability of the a-amylase also influenced by kilning. It is now shown that α-amylase is inactivated much less rapidly on the kiln than is β-amylase, so that the ratio of D.P./α falls throughout. The stability of the α-amylase is not only diminished by conditions favouring low D.P. in the finished malt, but may also fall during storage of the malt without important changes being otherwise observed in D.P. or α-amylase activity. Oat malts, though of low D.P., may show an α-amylase activity which is not inferior to that of barley malts.