Viscoelastic behaviour of masa from corn flours obtained by nixtamalization with different calcium sources.

The viscoelastic characteristics of nixtamalized corn masa were assessed by the dynamic oscillatory test. Masa samples were prepared with flours obtained by nixtamalization with different calcium sources: Ca(OH)2 (traditional), wood ashes (classic), CaCO3 (ecological), CaSO4 (ecological), CaCl2 (ecological), and Ca(C2 H5 COO)2 (ecological). A sample cooking without calcium source was used as control. Storage (G') and loss (G'') moduli were higher in masa from traditional and classic processes indicating a more elastic and viscous masa. Masa of flours from CaCl2 and Ca(C2 H5 COO)2 had the lowest values of G' and G''. Viscoelastic properties were explained in terms of the degree of starch gelatinization, the hydrolysis of pericarp and fibre content, the calcium-starch and calcium-zein interactions, as well as the presence of amylose-lipid complexes. Nixtamalization with Ca(OH)2 and wood ashes gave the best viscoelastic characteristics of masa.