Effects of extruded bleached nixtamalized maize pericarp on dry masa flour physicochemical properties
G. MONTEMAYOR MORA (1), E. Pérez Carrillo (1), H. Velázquez Reyes (1), M. Rostro Alanís (1), S. Serna Saldívar (1) (1) Tecnológico de Monterrey Campus Monterrey, , Mexico.
Pericarp is a byproduct of the dry masa flour industry used for animal feed. Nixtamalized dried pericarp was ground and extruded with bleaching agents with the aim of supplementing dry masa flours (DMF) without affecting color, water solubility and absorption indexes (WSI and WAI), and RVA parameters. Testing was conducted through a randomized design established 7 treatments: T0= extrusion without additives, T1 = enzymatic (<i>Lacasses from Pycnoporus sanguineus),</i> T2 = sodium metabisulfite, T3 = benzoyl peroxide, T4 = phosphoric acid, T5 = titanium dioxide 0.1% and T6 = titanium dioxide 0.2%. The treatments were extruded in a twin screw extruder Buhler® (BCTM-30). Flour blends were prepared as follows: 100% DMF and DMF substitution at 2, 5 and 10% by pericarp, generating a 7x3 factorial arrangement (treatment and substitutions, respectively). Extruded pericarp with the highest rate of expansion were T5 (1.39) and T6 (1.47). The T4 (1.57a, 11.58b), showed a decrease in a and b color in comparison to T0 (1.87a, 12.51 b). In case of DMF composite flours color (a, b) differed highly (P< 0.01) compared to the DMF control. Treatments with 10% replacement level presented the highest values of red (a) and yellow (b). Were not significant differences on the luminosity values (L) of flours. Higher values of WSI were presented as the level of substitution increased, T1 (1.95) presenting the highest. No significant differences for WAI were observed. Final viscosity values decreased as the percentage of pericarp increased, T1 (1377.3) was the smallest. In conclusion, the replacement of 2% of DMF with the extruded-ground pericarp treated with bleaching agents did not affect color, WSI, WAI and RVA properties. The use of extruded bleached pericarp to supplement dry masa flours represents an advantage in the industry because of the improvement in flour yield and dietary fiber content.
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