Resumo

ZEPEDA BAUTISTA, Rosalba et al. Nitrogen fertilization effect on the physical, structural and alkaline-cooking quality characteristics of grain from corn hybrids. Agric. Téc. Méx [online]. 2007, vol.33, n.1, pp.17-24. ISSN 0568-2517.

The objective of this study was to evaluate the effect of two nitrogen fertilization levels, 150 and 300 kg ha^-1 applied throughout fertigation on physical, structural and alkaline cooking quality characteristics of the grain of a group of 10 corn hybrids including hard, medium and soft seeded, and to identify those that meet the standards of the industry. Twenty samples of grain harvested in October 2002 in the Colegio de Postgraduados (CP), Montecillo, State of Mexico, Mexico and they were analyzed in February 2003 in the Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP), Chapingo, State of Mexico, Mexico for: 1) physical characteristics: hectolitric weight, flotation index and grain color, 2) structural components: percentage of pedicel, pericarp and germ, 3) alkaline cooking characteristics: moisture content of "nixtamal" and "tortilla", loss of solids, retained pericarp, color and yield of dough and tortilla. For data analyses a completely random design was used. Average from all hybrids, in comparison with 150 kg ha^-1 of N, the fertilization with 300 kg ha^-1 increased pericarp, germ and solid losses in 6.2, 5.0 and 2.4%, respectively; flotation index, pericarp loss (after lime-cooking) and grain color (reflectance) decreased 10.0, 9.4 and 2.2%, respectively and indirectly enhanced the white color of the dough and tortilla. In the hybrid CS 2*10 dough and tortilla yield was increased in 11.7 and 13.2%, respectively; hybrids CS 3*9 and CS 6* 10 showed a decrease in the flotation index of 19.5 and 10.5%, respectively. Hybrids CS 3*4, CS 3*9 and CS 2*5 meet the standards for tortilla production and CS 3*9, CS 6*10, CS 10*3, CS 2*10 meet those of the alkaline-cooking flour industry. The results showed that nitrogen fertilization modified in different proportions, alkaline-cooking tortilla and flour quality of hard, intermediated and soft corn grains.

Palavras-chave : Zea mays L.; dough; flotation index; nitrogen fertilization; tortilla.