Effect of sugar on the extrusion of maize grits and wheat flour

The influence of added sucrose on the degree of expansion and extent of starch conversion on extrusion processing of wheat flour and maize grits has been reported. Very different behaviour was found for the two cereal systems. In agreement with previous work, replacement of maize by sucrose at constant water content reduced the specific mechanical energy and as a consequence, reduced the degree of starch conversion and sectional expansion. In contrast, replacing wheat flour by sucrose even at levels as high as 20% of the flour weight had little effect. Possible causes discussed were less efficient plasticization of wheat flour by sucrose compared with maize grits at low water contents, a specific role for gluten and the larger particle size of maize grits compared with wheat flour.