A comparison of the quality of whole corn tortillas made from instant corn flours by traditional or extrusion processing

Abstract

Summary The nutritional quality (chemical and biological assays) was evaluated for tortillas made with two samples of instant corn flour prepared with 0.15 and 0.25% calcium hydroxide and processed either by extrusion or by the traditional process (nixtamalization). Both raw corn and the tortillas made from instant whole corn flours prepared by extrusion (TEP) had higher Protein Efficiency Ratio (PER), and Net Protein Utilization (NPU) values (p < 0.05) than tortillas prepared from traditional nixtamalization process. The Ca assimilation in the femurs bones of rats fed with raw corn, TEP (with 0.25% lime), and tortillas prepared from the nixtamal process, yielded lower values (p < 0.05) as compared with those shown by the rats fed with the other treatments of TEP (with 0.15% lime). The Ca, Mg, and P contents and protein quality of the treatments used in the feed affected some physical characteristics rat femurs (length, diameter, weight, breaking force, volume and density). The force required to break the femurs of rats fed diets of raw corn, tortillas prepared using the traditional process and without added protein, was measured and compared with the force required to break the femurs of rats fed with diets contain casein and TEP with either 0.15 and 0 0.25% lime. Those animals assimilating the lowest content of lime had the weakest femurs.