Improving Textural Characteristics of Tortillas by Adding Gums During Extrusion to Obtain Nixtamalized Corn Flour

Abstract

Whole white corn was ground, and lime, water and xanthan gum (XG, 0.5% w/w), carboxymethylcellulose (CMC, 0.5% w/w), guar gum (GG, 0.5% w/w) or a gums mix (XG, 0.25% w/w; CMC, 0.15% w/w; GG, 0.10% w/w) were added. Blends were extruded, dried and ground to obtain nixtamalized corn flour (ENCF), and they were used to make tortillas. The particle size distribution, particle size index, water absorption capacity (WAC) and water absorption index (WAI) were determined in flour; moisture content and viscoelastic characteristics (G′, G′′, tan δ) were determined in corn masa; tortillas were made, and texture (cutting force and rollability) and sensory evaluation were carried out. ENCF with XG and gums mix had the highest WAC, and tortillas were softer (33%) than tortillas from ENCF without gums. Corn masa viscoelasticity (tan δ) correlated negatively with tortilla firmness (r = −0.84). Corn tortillas made with XG and gums mix had acceptable organoleptic characteristics. PRACTICAL APPLICATION The extrusion process allows the using of the whole corn to make tortillas and reduce processing costs and the contaminant effluents (cooking liquor). The addition of a mix of gums during extrusion makes the corn masa retain more water and modify its rheological properties, improving masa handling characteristics and tortilla textural quality. The evaluation of masa viscoelasticity with the dynamic method makes it possible to differentiate corn masas and to select the best treatments.

Physicochemical and Rheological Changes of Starch in Nixtamalization Processes: Extrusion as an Alternative to Produce Corn Flour

“…Dynamic rheology has measured efficiently the viscoelastic properties of materials, especially starch [57]. Sahai et al [34] found a strong relationship between textural attributes of masa obtained from TPA, the particle size, and the composition.…”

“…Using other concentrations, the viscosity decreased. The viscosity in ENCF is also increased during the production process with the addition of gums [3,57] and enzymes [68]. The effect of alkaline cooking and lime concentration (from 0 to 1.0%) had direct impact on the viscosity of corn masa, when a Brabender amylograph was used to measure viscosity [6].…”

“…Mondragón et al [5] used small amplitude oscillatory rheometry to study the influence of lime and amylose-lipid complexes on the viscoelastic behavior of nixtamalized maize starch gels and observed that Gʹ and G″ showed to be lime dependent. Platt-Lucero et al [57] studied the viscoelastic behavior of masa obtained from rehydrated extruded corn flour and observed that Gʹ>G″ at any frequency and for any treatment. Quintanar-Guzmán et al [38] observed a similar behavior when the viscoelastic properties of corn were evaluated under different nixtamalization conditions.…”

“…The milling of the extrudates and particle size distribution (PSD) of the flour are important parameters that define the functional properties of ENCF [57]. Changes in starch structure are affected by particle size [14].…”

“…The NCF presents a high particle size index (PSI), a quality parameter used to compare different types of flours [57]. The PSI is an indirect measurement of mechanical damage occurring in corn grain [58].…”