A MODEL FOR THE PREDICTION OF BETA-GLUCANASE ACTIVITY AND BETA-GLUCANCONCENTRATION DURING MASHING

A mathematical model describing the effect of the mashing temperature program on dissolution and hydrolysis of beta-glucans is presented. In the model, dissolved beta-glucans are degraded by dissolved beta-gluc anases in the liquid phase. Increasing mashing temperature increases t he amount of soluble beta-glucans in the malt grist phase. Measurement s from laboratory scale mashings with different temperature profiles w ere used for the estimation of the model parameters for a malt produce d from the Finnish barley variety, Kustaa. The differences between the predicted and measured wort beta-glucan concentrations at the end of mashing were 0.04-0.12 g litre(-1) in laboratory scale mashings with d ifferent malts and in an industrial scale mashing experiment. beta-Glu canase activity in the liquid phase during mashing could be predicted with sufficient accuracy in all cases analysed. The simulation results showed that the lowest beta-glucan concentration was achieved when th e mashing-in temperature was 48 degrees C. Copyright (C) 1996 Elsevier Science Limited.