NIXTAMALIZATION IN TWO STEPS WITH DIFFERENT CALCIUM SALTS AND THE RELATIONSHIP WITH CHEMICAL, TEXTURE AND THERMAL PROPERTIES IN MASA AND TORTILLA

Abstract

ABSTRACTThe present investigation evaluated the chemical and thermal properties using lime and alternative calcium salts, and their effect on the characteristics of masa and tortilla obtained in a two‐step nixtamalization process. White dent corn was cooked in calcium hydroxide solution (1.2% [w/v]; 1:3 maize : water ratio) at 80C (30 min), and the calcium hydroxide was replaced either by calcium chloride or lactate at calcium equilibrated concentration (30 min), and steeped in a cooking solution for 2,400 min. Grains were analyzed for water and calcium absorption, and apparent diffusion coefficients were calculated. Thermal properties of flour made from these grains were also determined. Additionally, the masa and tortilla made with nixtamalized corn flours were analyzed for texture and color, and an acceptability test was performed on the tortilla. Water absorption showed a notable increase during cooking, approaching an asymptotic maximum absorption after 8 h of steeping for all treatments. The maximum calcium absorption was obtained in stepwise nixtamalization with solutes of CaCl2 and C6H10O6Ca. The water apparent diffusion coefficients were adequately described by Fick's model and it was found that C6H10O6Ca showed the highest value (5.5901 × 10−10 m2/s), while that for calcium diffusion the model gave low fits. The thermal analysis showed that gelatinization temperatures were affected significantly (P < 0.05) by the cooking and steeping times, while the gelatinization range and enthalpy were affected significantly (P < 0.05) by salt type. The masas and tortillas obtained from all treatments presented good texture and color characteristics in comparison with the commercial flour. Sensory analysis showed that the tortilla nixtamalized with C6H10O6Ca was the most acceptable to consumers.PRACTICAL APPLICATIONSThe main contribution of the present study is the utilization of different salts as an alternative to calcium during cooking and steeping in a two‐phase nixtamalization process. The different calcium salts provide an option to avoid undesirable changes in the products' quality characteristics present in the typical nixtamalization process produced by high lime concentration. At the same time, these alternatives could contribute to reduced environmental pollution, specifically in the waste water (decreased pH and the solids). A prediction model for water and calcium absorption during the nixtamalization process is proposed for the different calcium salts. The physical, chemical and thermal changes that occur in the nixtamalization in the different treatments for the different calcium salts were related to color and texture characteristics of masa and tortilla as well as tortilla acceptability.