Nixtamalization process

Figure 3. The 18 corn varieties used to study the nixtamalization process. Variety names correspond to those indicated in Table TV.

Calcium Content of Starch Isolated from Lime-Treated Corn. Starch is the major component of the corn grain and derived products (see Table VII). To explore in more detail the distribution of calcium after the nixtamalization process, calcium was measured in starch isolated from untreated and lime-treated com. These analyses (see Table VIII) indicated that calcium was fixed or bound in some way to the starch. There was approximately 2.9 times more calcium in starches isolated from lime-treated corns than in starches isolated from untreated grains. Figure 7 shows micrographs of isolated starches. 

The Requirement of a Divalent Alkaline Earth Metal. Lime-treated corn produces a dough whose functional properties depend on the pasting characteristics of starch. The hydroxides of different alkaline earth metals were tested to determine whether they could replace calcium in the nixtamalization process. It was not possible to prepare tortillas with adequate sensory or mechanical properties from corn treated with... 

The concentration of lime used in the nixtamalization process is ten times in excess of the saturation point. After cooking and steeping, about 40% of the original calcium ion remains in the lime water suspension. Of the 60% of calcium removed, about one-third is associated with the... 

A further beneficial feature provided by the alkaline medium during the nixtamalization process is the destruction of aflatoxins in com contaminated by Aspergillus flavus (25). 

Nixtamalization Process developed by early Mesoamerican civilizations in which whole com is cooked in water containing wood ashes or lime (calcinm hydroxide). The grain is cooked to partially gelatinize the starch and stone gronnd to produce a dough, which is further processed into dry masa flour, table tortillas, tortilla chips, or com chips. 

Most manufacturing processes do not detoxify aflatoxin and therefore if the aflatoxins are not detected, products will be marketed. One of the processes used for reducing aflatoxin levels is nixtamalization (alkaline cooking), which is used during the making of corn tortillas, tortilla chips, and corn chips, and gives a 51 to 78% reduction in aflatoxin levels (Torres et al., 2001). 

American natives knew that corn needed to be processed to be nutritious in a process known nixtamalization (alkaline treatment commonly used in Mexico and Central America in the preparation of tortillas, tamales and hominy) or ingested as immature ears. This knowledge was lost when Christopher Columbus returned from the New World with samples of the new seed. 

Dunn, M., Serna-Saldivar, S.O., Sanchez, D., and Griffin, R.W. 2008. Commercial evaluation of a continuous micronutrient fortification process for nixtamal tortillas. Cereal Chem. 85(6) 746-752. 

The nixtamal pH correlates to the lime absorbed during cooking and steeping, and the amount of washing. The pH affects flavor, texture, and color of processed products. 

Cereals are considered a very poor source of calcium (Sema-Saldivar 1993). However, some food processes such as nixtamalization for tortilla making (Chapter 9) and cooking in the presence of ashes (i.e., alkaline to. Chapter 16) increase its concentration (Sema-Saldivar et al. 1990, 1991, 1992). Phosphorus is the mineral present in the highest amounts unfortunately, its bioavailability is questionable because most is bound to phytic add (Lasztity and Lasztity 1990). Phytates also bind other cations such as iron and zinc, considerably lowering their availability. The phytic acid... 

---