Anthocyanins of blue corn (Zea mays) Inocuous substances? Part 5. Bibliographic review of progress in the last 10 years

Abstract

In Mexico, the cradle of corn (Zea mays), it is consumed in grain, roasted (ízquitl⁸), ground (pinole⁹), fermented (pozol¹⁰), and nixtamalized¹¹ (production of tortillas and tamales). With the consumption of maize, the Mexican population satisfies up to 70% of its energy needs, 50% of proteins and 37% of total calcium when it is consumed in the form of a tortilla. Nixtamalization is an

important process to improve the nutritional value of corn. When the grain is leached in water and CaO (1-3%) at 95-100°C for 60 to 180 minutes and letting it rest for 12-24 hours, then washing it with water to remove excess lime, cooked maize or nixtamal is obtained. This process produces structural and chemical changes modifying the texture, color, and flavor of the grain, increasing its digestibility and the isoleucine/leucine balance, making better use of the protein and producing the release of part of the niacin that is not initially bioavailable in the grain. It seems obvious to think that this procedure can damage the colored maize kernels. In fact, in pre-Hispanic cultures only white maize was nixtamalized. In the last decades, the use and consumption of colored maize, even nixtamalized, has become popular. This bibliographic review presents what has been published in the last ten years in this regard. It can be concluded that the nixtamalization of blue corn is affecting its anthocyanin content and, probably, its possible benefit to the health of those who eat them already modified. Further in vivo studies should be performed to corroborate these points.