An investigation into proteolysis in mashing

Using the Bradford assay that measures total protein, there is a detectable lowering of polypeptide that occurs as the temperature is raised to conversion temperature, though not at the lower temperature (45 o C) at which mashing was started. However, this decrease in total soluble protein is not enzyme catalysed. There appears to be no impediment to proteinase action in mashes, as added proteolytic enzymes can lower the level of detectable protein. Comparison of worts made from the same malt using a Hot Water Extract procedure and a Cold Water Extract test illustrates that the protein distribution in the latter (monitored using SDS‐polyacrylamide gel electrophoresis) is much the more complicated. It is concluded that proteolysis does occur in mashes through the action of endogenous proteinases, but that this does not manifest itself in a detectable change in soluble protein as measured by a general protein assay procedure. © 2020 The Institute of Brewing & Distilling