Relationship between structural and biochemical characteristics and texture of corn grains

Abstract

AbStRACt. The texture of corn grains is a fundamental characteristic for the industry as well as for grain producers and processors. To further understand the mechanisms involved in grain hardness, contrasting corn cultivars for grain hardness and protein quality were evaluated. The cultivars were Cateto L 237/67 (hard endosperm and low protein value), QPM BR 451 (semi-hard endosperm and high protein value); Bolivia-2 (floury endosperm and low protein value), and Opaque-2 (floury endosperm and high protein value). Evaluations were carried out at 10, 20, 30, 40, 50, and 60 days after pollination in developing corn grains and in the mature grain. In developing grains, evaluation consisted in the determination of the area, percentage of starch granules, distribution of starch granules, and protein bodies in the endosperm. In mature corn grains, the parameters evaluated were: density, percentage of total proteins, levels of lysine and tryptophan, and banding pattern of zeins. The results 499©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 7 (2): 498-508 (2008) Corn grain texture indicate that the higher physical resistance of corn grains from the cultivars analyzed is influenced by the high percentage of total proteins, high synthesis of 27-kDa zeins, presence of protein bodies, and perfect organization of starch granules in the endosperm, independent of their sizes.

Effect of Different Corn Processing Techniques in the Nutritional Composition of Nixtamalized Corn Tortillas

“…It is known that MF industry prefers hard endosperm maize, as opposed to TM that favours white landraces [17]. Previous studies report PC, on dry basis, for MD tortillas of 7.58-15.63 g/100 g [10,[18][19][20][21].…”

“…Previous studies report PC, on dry basis, for MD tortillas of 7.58-15.63 g/100 g [10,[18][19][20][21]. These reports have different maize descriptions, suggesting phenotypes were different; but also is known PC varies according to endosperm hardness [17]. However, on dry basis, results between MD and MF, were similar (p>0.05) and differences, per 100 g of fresh weight, are due to losses that take place during cooking, pericarp removal and wet milling of nixtamal in TM [5,21].…”

Characterization of corn landraces planted grown in the campos gerais region (Paraná, Brazil) for industrial utilization

“…In the Table 5 Pereira et al (2008) reported that corn kernels with hard or dent endosperms have abundance of organized protein bodies what explain the compact of these endosperms. A positive correlation was observed between lipid content and kernel real density (r = 0.67, at 95 % of confidence).…”

Desarrollo y evaluación de nuevo germoplasma de maíz (Zea mays L.) para uso especial en Argentina

“…No se registraron diferencias estadísticas para contenido de triptófano sobre proteína total entre líneas endogámicas CIG tipo CP con endosperma harinoso y las que tienen granos con endosperma vítreo o modificado (±t Student = 1,9; n.s.). Los resultados presentados en la Tabla 4.26 también coinciden con datos de varios autores (Wallace et al, 1990;Lópes et al, 1995;Azevedo et al, 2003;Krivanek et al, 2007;Pereira et al, 2008) que señalaron que seleccionar materiales con alta calidad proteica y endosperma duro conlleva a una cierta reducción de la calidad proteica respecto del opaco-2 en su estado puro porque aumenta la proporción de las prolaminas α-zeína y, sobre todo, hasta 2 y 3 veces la γ-zeína, ambas determinantes de la mayor dureza del grano (Paiva et al, 1991; DombrinkKurtzman y Bietz, 1993) pero pobres en aminoácidos esenciales.…”

“…Pereira et al, 2008;Sánchez et al, 2007;Krivanek et al, 2007). El triptófano puede fluctuar desde 0,2% a 0,5% (media= 0,4%) para maíz normal o desde 0,5% a 1,9% (media= 0,8%) para maíz de alta calidad proteica (Moro et al, 1996;Balconi et al, 1998;Krivanek et al, 2007 Gevers (1975).…”