Chemical, rheological and mechanical evaluation of maize dough and tortillas in blends with cassava and malanga flour.

Masa or dough from nixtamalized maize with cassava (Cf) and malanga flour (Mf) addition at 20, 30 and 40 % (w/w) were prepared making seven treatments. The produced masas or doughs were subjected to chemical analysis, rheological and mechanical tests. Tortillas were manufactured from these doughs and mechanical tests were undertaken. Doughs from tubers had less protein and lipid content but higher nitrogen free extract than the control. All doughs presented weak viscoelastic gel-like behavior, with those of Mf behaving mainly as viscous systems. Doughs with Cf showed lower decrease in both the elastic (G') and viscous (G") moduli than those with Mf. The adhesiveness and cohesiveness of doughs with Mf showed a higher reduction of maximum force than those with Cf. Tortillas with Cf were more elastic with higher tensile strength than those with Mf. Using Cf as partial substitution of maize might lower production costs, but Mf is not particularly suitable as maize substitute in tortilla production. Tortillas with 40 % (w/w) cassava flour, presented the highest preference on a sensory test.