Effect of Kefiran on Mixolab Thermomechanical Properties of Weak Wheat Dough

Abstract

Kefiran is an exopolysaccharide which is produced mainly by lactic acid bacteria and fungi in kefir grains during growth. In this study, Kefiran added at levels of 0.5, 1 and 1.5% w/w (flour basis) to wheat flour and its effects on the wheat dough behaviour subjected to a dual mechanical shear stress and temperature constraint using the Mixolab device have been studied. Results of Mixolab evaluation of dough showed that 1.5% Kefiran concentration induced the greatest benefits on wheat dough behaviour during mechanical shearing and thermal treatment resulting in a significantly increased water absorption, dough development time and stability and decreased dough departure time and stability during mixing. Increasing the amount of Kefiran from 0.5% to 1.5% increases in cooking stability, but dough maximum torqe (viscosity) increased or decreased significantly with increasing kefiran concentration, Nevertheless, dough thermal weakening and minimum torque did not change significantly (P<0.05). Increasing Kefiran (1.5% concentration) resulted in decreasing of protein weakening and gelatinization rates and also lowered the degree of starch breakdown which may be beneficial for bread with delayed tailing effects. Therefore, Kefiran may play an important role in improving of rheological properties of weak dough and its processing conditions. Keywords: