Hagberg penetrometer method for α-amylase activity in sprouted grain: Prediction of activity of flour blends

A penetrometer method for sprout damage has been applied to New Zealand flours, and a close relationship between the results and crumb doughiness in bread has been demonstrated. The pressure-sustaining capacity of the flour gels, as calculated from the penetrometer readings, is inversely proportional to the enzyme activity. A simple relationship exists between penetrometer number and the proportion of flour from sprouted grain in flour blends. The penetrometer number appears to be primarily determined by the α-amylase activity of the flour from sprouted grains and to be unaffected by variations in the level of ‘damaged’ starch in the flour. A method is proposed whereby the amounts of sprouted lines of wheat necessary in a grist, to produce flour with a predetermined level of activity, may be calculated.