Effect of Wheat Starch on Imitation Cheese Texture

This study was undertaken to determine if partial replacement of the rennet casein protein with native wheat starch (at 0-20% levels) in the formulation of imitation cheese would affect the textural properties of the final product. Increasing levels of starch to 5% levels significantly increased the hardness of the imitation cheese from 128N-146N. The peak stress values of imitation were significantly increased from 425 kPa for the control to ~510 kPa at the higher levels of starch addition (5-9%). The stress relaxation times increased significantly from 35.3 sec control to 140 sec with increasing levels of wheat starch to 9%, possibly indicating reinforcement of the product through amylose and amylopectin association. Cohesiveness was significantly reduced with increasing levels of wheat starch from 0.151 for the control to 0.113 at 9% starch levels. The reduction in the cohesiveness of imitation cheese by starch was due to reductions in the protein content and possibly by stress localisation at the starch-protein matrix interface. Results are indicative that the starch functioned as a filler allowing the casein to dominate the products textural properties.