Froylán Rincón Sánchez

Relationships Between the Microstructure, Physical Features, and Chemical Composition of Different Maize Accessions from Latin America

ABSTRACT Chemical composition (moisture, total lipids, protein, and apparent amylose) and some physical features (1,000 kernel weight, hardness, and anatomical composition) were determined in 71 accessions representing races of maize from Latin America. Their microstructural characteristics (size and compaction of endosperm cell bodies, pericarp thickness, horny-floury endosperm ratio, and morphology and size of starch granules) were also evaluated using environmental scanning electron microscopy (ESEM). Compaction was the most important microstructural feature of the maize kernels, representing kernel hardness. Highly compact kernels tended to be hard, with high protein, pericarp, and hard-endosperm content and high pericarp thickness, but with low moisture, amylose content, and kernel weight and size. The opposite was observed in the least compact kernels. Highly compact kernels tended to have small, polygonal starch granules (<10 μm), while the least compact kernels contained large, spherical granules ...

Kernel microstructure of Latin American races of maize and their thermal and rheological properties

ABSTRACT Seventy-one races of maize representing races from Latin America were analyzed for microstructural features such as the degree of compaction of the endosperm cell bodies, starch granule size and morphology, and hard-soft endosperm relationship. Flours were analyzed using rapid visco analysis and differential scanning calorimetry. Compaction grade was the most important microstructural feature of the maize kernels that related to thermal and rheological properties. Highly compact kernels developed low peak and final viscosities; small, polygonal starch granules; and required more time and higher temperature to gelatinize. The opposite was the case for less compact kernels. This indicates that the characteristic protein matrix of highly compact kernels represents a physical barrier to water migration into the granules, retarding the gelatinization process.