Materials based on maize biopolymers: Effect of flour components on mechanical and thermal behavior

The present study describes the effects of glycerol, relative humidity (RH) and the minor components of corn flour on mechanical and thermal properties of native flour, defatted flour, and starch-based materials. The kinetic of retrogradation for these different materials were dissimilar. For all samples, strain at break shows a maximum value as a function of RH followed by a decrease, explained by the appearance of water and glycerol clusters. Starch controls the mechanical properties of corn flour-based material and their variations with temperature and humidity. Lipid and protein have negative effect on mechanical properties of thermoplastic flour toward starch but they did not have a plasticizing effect on the physicochemical behavior of the matrix. T(g)s decreased as a result of water content increase.