Relationship between Consistency of Wheat Grain and Flour Diastatic Activity

Abstract

THERE are annually harvested in Australia more than 100 varieties of wheat, one of the chief reasons for this large number lying in the complexity of soil-type and climate encountered throughout the wheat-belt. It will be appreciated that a considerable diversity of quality types are represented by these varieties and in 1956 a phenomenon referred to as ‘over-stability’, characteristic of certain extremely vitreous material, received much attention. Flours obtained from these varieties were found to contain a high percentage of damaged starch, arising out of the increased roll-pressure it was necessary to exert on the grain in order to obtain a satisfactory flour yield. Consequently the diastatic activity of these flours was considerably augmented, and the increased dextrinization associated with this high diastatic activity imparted stickiness to the fermenting dough, the resultant loaves being dense, of low volume and poor, waxy texture. In order to ascertain which of the varieties being grown possessed this characteristic and were thus unsuitable for cultivation, a great number of varieties were tested for grain consistency and diastatic activity, and the relationship revealed between these two characteristics forms the subject of this communication.