Mineral content in Mexican white corn and the effect of" nixtamalizacion"(lime-cooking)

Abstract:

Minerals are very important food components. They are of nutritional, functional and in some case toxic importance. In cereals, the mineral content of the kernel is concentrated in the brand layer and its affected by several factors including soil and agricultural practices. In Mexico, corn is the most important cereal in the diet, with an annual per capita consumption of over 80 kg. Corn is planted all over Mexico and its mineral content is expected to vary from region to region. Our objective was to investigate the mineral content of 29 commercial white corn samples from different parts of Mexico and to estimate the effect of a commercial corn lime-cooking process on the mineral content of the resulting masa and tortilla. Total ash, iron, zinc, cadmium and lead were quantified using Atomic Absorption spectroscopy. Statistical analysis was used to evaluate the relationships between the variables. A large variation in the iron and zinc content of white corn was observed. Mean iron content was 2.04 mg/100 g with a coefficient of variation (CV%) of 24%, while mean zinc content was 3.48 mg/100 g with CV of 63%. In all samples cadmium and lead was found to be below the detection limit of the method, 1 a 2 ppm, respectively. Based on their origin, samples were classified in four regions; however no significant differences were found between iron and zinc contents between the regions. Lime-cooking had a significant effect on the iron and zinc content of corn. Average losses were found to be 15% for iron and 20% for zinc (dry basis). These results indicate that Mexican corn vary in its iron and zinc content and this effect must be considered for labeling corn …

Año de publicación:

2005

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