Rheological and thermal properties of dough and textural and microstructural features of bread obtained from nixtamalized corn/ wheat flour blends A.Y. Guadarrama-Lezama a , H. Carrillo-Navas b , E.J. Vernon-Carter b , J. Alvarez-Ramirez b, * a Facultad de Química, Universidad Aut onoma del Estado de M exico, Paseo Col on esq. Paseo Tollocan s/n, Col. Residencial Col on, C.P. 50120, Toluca, Estado de M exico, Mexico b Departamento de Ingeniería de Procesos e Hidr aulica, Universidad Aut onoma Metropolitana-Iztapalapa, San Rafael Atlixco No. 186, Col. Vicentina, C.P. 09340, M exico, D.F., Mexico article info Article history: Received 28 September 2015 Received in revised form 9 March 2016 Accepted 10 March 2016 Available online 11 March 2016 Keywords: Dough Nixtamalized corn flour Thermal properties Viscoelasticity abstract Bread made with corn flour has a rich tradition in several countries. On the other hand, nixtamalization is a process conferring malleability and functionality to corn flour via calcium incorporation. The aim of this work was to study the rheological and thermal properties of dough, and the textural and microstructural features of bread obtained from nixtamalized corn (NCF)/wheat flour (WF) blends. Thermal analysis indicated that NCF promoted the interaction between starch molecules and lipids. The incorporation of NCF improved the viscoelasticity of dough, indicative that the participation of lower amounts of gluten (protein) due to WF substitution by NCF might be compensated by the cross-linking capacity of calcium ions. Morphological analysis via SEM showed that as NCF was incorporated, a more compact and porous microstructure arose that caused breads to exhibit increasing hardness, but a decrease in the rest of the textural characteristics. Increasing amounts of NCF led to more homogeneous bread crust color, char- acterized by a more subdued lightness and yellow hue. Overall, NCF offers a mean to improve dough viscoelasticity and granular microstructure of wheat-based bread. © 2016 Elsevier Ltd. All rights reserved. 1. Introduction Bread made with wheat flour accounts for about 50% of dietary energy requirements in many countries. Although flours from other botanical sources offer also high carbohydrate contents, the wide- spread usage of wheat flour for bread making can be attributed to its relatively high gluten content. Wheat proteins have the ability of developing a viscoelastic network when the flour is mechanically blended with water. In turn, the viscoelastic network allows an easy manipulation of dough for fabrication of a wide diversity of spe- cialties. Besides, the viscoelastic matrix enables the retention of the gas produced during fermentation, leading to aerated crumb bread morphology. It has been recognized that high costs of wheat importation in regions where climatic conditions do not favor its cultivation (e.g., tropical and sub-tropical Africa) limits its utilization as a source of dietary energy (Goodall et al., 2012). This problem has been addressed by the use of flours from non-wheat botanical sources, including rice (Torbica et al., 2010; Torres et al., 2014), chestnut (Demirkesen et al., 2010; Torres et al., 2014), soybean (Ribotta et al., 2004) among others. Results obtained with non-wheat flours are motivating, although some problems related to dough viscoelas- ticity and bread texture require further research (Berta et al., 2015). On the other hand, the bread production in underdeveloped eco- nomic and impoverished regions has been addressed by using inexpensive flour from local botanical sources, like cassava (Onyango et al., 2011), and sorghum (Schober et al., 2005). Corn flour has been also considered for bread production (Brites et al., 2010; Falade et al., 2014). Besides its low-gluten content, corn is cultivated in many countries with large climate diversity. The use of corn flour for bread preparation has an ethnic tradition in some countries. Pan de Elote in Mexico and Broa in Portugal are examples of traditional bread recipes incorporating corn flour. Given the reduced protein content (about 2% w/w) of corn flours, the bread production is confronted with some challenges, including weak viscoelastic networks and poor gas retention capacity. In this * Corresponding author. E-mail address: jjar@xanum.uam.mx (J. Alvarez-Ramirez). Contents lists available at ScienceDirect Journal of Cereal Science journal homepage: www.elsevier.com/locate/jcs http://dx.doi.org/10.1016/j.jcs.2016.03.011 0733-5210/© 2016 Elsevier Ltd. All rights reserved. Journal of Cereal Science 69 (2016) 158e165