Effect of Different Corn Processing Techniques in the NutritionalComposition of Nixtamalized Corn Tortillas

摘要

Maize in the form of tortilla plays an important role in the diet of Mexican population, with a per cápita consumption of 157 g/day. The two main methods for tortilla are the traditional method, which uses maize dough or masa made in the ancient manner; and the industrial method, which uses industrially-processed maize flour. Both methods are based on the alkaline-processing of maize known as nixtamalization. Chemical profiles of maize tortillas were analyzed. Samples were collected between 2012 and 2013 in three lots, one every six months, from four retail shops at 16 municipalities of Mexico City; tortillas made of maize flour were obtained from two supermarkets of four municipalities. Composition changed according to raw materials and production method. Samples made with nixtamal dough showed lower contents of moisture, of about 5%, and absence of thiamine and riboflavin than nixtamal flour. Differences in carbohydrates and iron, 0.5% more in case of iron, may be caused by maize phenotype; while differences in crude fat 1% more, dietary fiber 0.5% more, thiamine, and riboflavin are due to additives added by manufacturers; however, concentration of vitamins and minerals in the final product were below theoretical values. In case of calcium, 100% more in maize dough tortillas is due to lime amount added on each method or amount of broken grain processed. Regarding on effect of sampling, contents of protein and crude fat remained constant on dough tortillas regardless of sample collection and these were consistently higher than maize flour tortillas over time, 0.3% and 1%, respectively, which is due to maize phenotype. On flour-made tortillas, fat and dietary fibers were also constant since maize flour manufacturers add additives and nutrients to obtain certain rheological characteristics and nutritional content on maize flour tortillas.