AATCC 103-2019 is intended for the assay of bacterial amylases employed commercially for textile desizing. It is not applicable to products which contain beta-amylase in addition to alpha-amylase. Dextrogenic amylase activity is measured in terms of digestion time required to produce a color change denoting a definite stage of dextrinization of the starch substrate. The amylase content of the sample, expressed in Bacterial Amylase Units (BAU), is readily calculated from the dextrinizing time.