Explorative Study of Reactive Extrusion over Nixtamalization‐Maize Pericarp Residue: Effect on Dietary Fiber, Resistant Starch, and Nixtamalized Corn Flour Tortillas

Interest in clean label products and decrease of effluents have increased. Nixtamalized maize flour (NMF) residues could be used as by‐products that modify NMF properties without the need for other additives. In this work, pericarp residue of NMF is subjected to reactive extrusion (REX) using 1% or 5% addition of phosphoric acid, sodium metabisulphite, benzoyl peroxide, or titaniumdioxide. The use of pericarp as an ingredient for cereal products has detrimental effects. Dietary fiber content, resistant starch, and moisture are studied to characterize the REX treatment products. Maize compound flours with 5% REX extruded maize pericarp are prepared. The apparent viscosity parameters of composite flours and the physical characteristics of maize tortillas with the compound flours are analyzed. Pasting properties of compound flours is modified with chemical treatment. All REX tortilla treatments show a reduction in thickness without effect on resistance and extensibility, which can positively affect the yield of the product without impact on quality. Compared with control and other treatments, the addition of tortilla produced with phosphoric acid extruded material has the highest resistance to extension after 24 h of production. The pericarp residue of maize nixtamalization is successfully converted into a by‐product of maize dough production. Reactive extrusion (REX) produces rheological changes in the material that modifies the properties of maize tortillas prepared with 5% (w/w) of the chemically treated and extruded maize pericarp treatments (CEMPs).