The research, conducted by scientists from the Benemérita Universidad Autónoma de Puebla and Mexico’s National Institute of Forestry, Agricultural and Livestock Research (INIFAP), set out to evaluate the physical and colorimetric characteristics of grain, its hydration behavior during nixtamalization, and the texture of tortillas prepared from sixteen native maize races. Samples were gathered between November and December 2022 from municipalities spanning altitudes from roughly 1,280 to 2,650 meters above sea level, capturing the steep environmental gradients that have shaped maize evolution in central Mexico. Each race was represented by ten morphologically representative ears, identified through visual examination by the head of INIFAP’s germplasm bank and supported by specialized literature.

Once shelled and dried to thirteen percent moisture, the kernels were analyzed at the Maize Quality Laboratory of the Valle de México Experimental Station in Coatlinchán, Texcoco. The team employed a completely randomized design with two replicates per race, subjecting each population to a battery of standardized tests. Grain hardness was assessed using the flotation index, an indirect but widely adopted measure in which kernels are immersed in a brine solution and classified from very hard to very soft. Hectoliter weight and hundred-grain weight provided complementary measures of density and kernel size, while a Hunter Lab colorimeter quantified luminosity, hue angle, and chroma using the CIELAB color space. Tortilla texture was measured with a Brookfield CT3 texture analyzer, recording the force and distance required to tear fresh tortillas and samples stored for twenty-four and forty-eight hours.

The statistical verdict was unambiguous. Analysis of variance revealed highly significant differences among the sixteen races for every variable examined, from endosperm hardness and hectoliter weight to nixtamal moisture, dough moisture, tortilla moisture at three time points, solids loss during cooking, and all colorimetric parameters. The races spanned the full spectrum of endosperm texture, from very hard to very soft, with hectoliter weights differing by as much as forty-one percent and hundred-grain weights by thirty-four percent between the extremes. This breadth of variation, the authors note, reflects both the deep genetic diversity of Mexican maize and the genotype-by-environment interactions that have sculpted kernel traits across Puebla’s altitudinal gradients.

Some of the most interesting findings concern the races themselves. The Pepitilla race from Huaquechula produced very hard kernels with a flotation index between zero and twelve, along with the highest hectoliter weight of 79.2 kilograms per hectoliter, while the Arrocillo races clustered in the hard category. At the opposite end, the Elotes Conicos, Chalqueño, and Zapalote Chico races exhibited very soft endosperm, with flotation indices approaching the maximum of one hundred. Notably, Chalqueño also produced the largest kernels in the study, with a hundred-grain weight of 58.5 grams, more than double that of several other races. These soft-textured grains hydrate rapidly during nixtamalization, a property that generally translates into superior dough and tortilla quality, and the data bore this out: races with floury endosperm absorbed the most water in both the nixtamal and the masa.

Moisture dynamics during nixtamalization told a coherent story. Nixtamal moisture ranged from 42.8 percent in Arrocillo Yellow to 50.6 percent in the second Pepitilla population, exceeding the 36 to 42 percent range set by the Mexican standard NMX-034. Dough moisture spanned 54.1 to 60.4 percent, and freshly made tortillas varied from 37.2 to 48.3 percent. The Pepitilla race recorded the most suitable moisture values across the process, while Chalqueño showed the lowest. Solids loss during cooking, an indicator of dry matter sacrificed to the alkaline cooking water known as nejayote, ranged from 1.9 percent in Arrocillo Red to 5.2 percent in Pepitilla, with the hardest grains losing the least material, a pattern consistent with the established relationship between endosperm texture, pericarp detachment, and nixtamalization efficiency.

Color proved to be one of the most visually dramatic dimensions of the study. The sixteen races encompassed cream, white, yellow, blue, orange, and red grains, and the colorimetric data captured this spectrum in detail. Chalqueño, with white grain, posted the highest luminosity at 71.8 percent and the highest hue angle at 85.8, while the red-grained Arrocillo Red registered the lowest luminosity at 21.6 percent. The orange Conico and Conico Yellow races showed the highest chroma values, at 38.0 and 37.1 respectively, indicating the most saturated color, whereas the blue Elotes Conicos populations fell to chroma values as low as 4.3. The authors highlight the red Arrocillo and white Chalqueño as the most strongly contrasting pair, driven mainly by differences in the relationship between luminosity and hue, a reminder that pigmentation in native maize is not merely aesthetic but tied to anthocyanin and carotenoid profiles with potential nutritional and market value.

Tortilla texture measurements added a technological layer to the picture. Breaking force for freshly prepared tortillas ranged from 90 gram-force in Pepitilla to 251 gram-force in Arrocillo Cream, and after forty-eight hours of storage the spread widened further, from 113 to 340 gram-force. Breaking distance followed a similar trajectory, with the blue Elotes Conicos races producing tortillas that remained soft even after two days of refrigerated storage. The team explains that tortilla texture is intimately linked to moisture content: higher water levels plasticize the starch-protein matrix, increasing flexibility, while moisture loss during storage accelerates starch retrogradation and hardening. Interestingly, the breaking forces recorded here were substantially lower, nearly half, than those reported in an earlier study of improved maize varieties, suggesting that native races may yield tortillas with a distinctly softer, fresher bite.

The broader implications extend well beyond the laboratory bench. Mexico harbors an estimated 59 to 64 native maize races, and Puebla alone hosts at least fourteen, making it one of the country’s principal centers of maize racial diversity. In 2023 the state harvested 420,898 hectares of maize, ninety percent of it native, cultivated by roughly 994,000 small-scale producers across 28,400 communities. Yet this system faces mounting pressures from cultivation abandonment and genetic erosion. By documenting the technological potential of races traditionally relegated to niche uses, such as the popcorn-type Arrocillo varieties, the study argues that agrobiodiversity conservation and industrial innovation are complementary rather than competing goals. Races with soft endosperm and favorable moisture profiles could feed directly into breeding programs and value-added product development, giving farmers new economic reasons to keep planting what their grandparents planted.

Ultimately, the research delivers a quantitative vindication of millennia of farmer selection. The sixteen races from Puebla are not uniform primitives awaiting replacement by modern hybrids; they are finely tuned instruments of flavor, texture, and color, each adapted to specific agroecological niches and culinary traditions. As the authors conclude, this diversity positions native maize races as reservoirs of agrobiodiversity and strategic resources for conservation, food use, the masa and tortilla industry, and sustainable breeding. In a world grappling with climate change and dietary homogenization, the humble tortilla may prove to be one of the most delicious arguments for preserving genetic diversity ever measured in a texture analyzer.

Subject of Research: Grain, masa, and tortilla quality of native maize races from central Mexico

Article Title: Grain, masa, and tortilla quality of native maize races from Central Mexico: valuing agrobiodiversity for conservation and food use

Article References: López-Morales, F., Vázquez-Carrillo, M. G., Reyes-López, D., Avendaño-Arrazate, C. H., De La Cruz-De Jesús, M. Y., Hernández-Domínguez, C., García-Cruz, L., & Zaldívar-Martínez, P. (2026). Grain, masa, and tortilla quality of native maize races from Central Mexico: valuing agrobiodiversity for conservation and food use. Frontiers in Conservation Science, 7, Article 1924963. https://doi.org/10.3389/fcosc.2026.1924963

Image Credits: AI Generated

DOI: 10.3389/fcosc.2026.1924963

Keywords: native maize, agrobiodiversity, nixtamalization, tortilla quality, maize races, Puebla, plant genetic resources, grain hardness, food security, conservation, masa, Mexico