Composition and thermal properties of starch in flint maize (Zea mays, L.) kernels: location and crop management effects

Marcos ACTIS, Abel Farroni, Fernando Andrade, Oscar Valentinuz, Alfredo Cirilo

Resumen


Starch composition and its thermal properties of maize (Zea mays, L.) kernels are relevant for the corn-flake industry since starch gelatinization is involved in the manufacture process. Moreover, starch composition also affects kernel hardness which modifies kernel behavior in the dry-milling industry that provides the flaking-grits for the corn-flake manufacture. According to this, it is important to know if the environment and agronomic management where the crop grows affect the starch composition and its thermal properties. The objective was to analyze the effect of different crop environments and management practices at the main maize-production area of Argentina on starch composition and its thermal properties of flint maize kernels. The amylose and starch content were determined. The starch thermal properties were analyzed by differential scanning calorimetry (DSC): onset and peak temperatures (ToG, TpG), temperature range (RG) and gelatinization enthalpy (ΔHG), in addition to the peak height index (PHI). Amylose/starch ratio in kernels was increased from the southern location to the northern one according to the mean temperature during the post-silking period. Amylose deposition in the endosperm of kernels also increased as crop post-silking biomass production was improved according to better growing conditions, yielding flintier and weightier kernels. Starch gelatinization onset and peak temperatures, gelatinization enthalpy, and peak height index were positively associated with amylose concentration and amylose/starch ratio, whereas the gelatinization temperature range was negatively associated with both kernel attributes. The reported effects on starch composition and its thermal properties of kernels would be of interest for the industry in order to better estimate kernel quality to be expected according to how and where maize was produced. Future studies including more locations and hybrids are needed to confirm the reported findings of environmental effects on starch composition and thermal properties in flint maize kernels.


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