Resumo

PINEDA-GOMEZ, P et al. Role of water in maize starch gelatinization: an study by Differential Scanning Calorimetry. ing.cienc. [online]. 2010, vol.6, n.11, pp.129-141. ISSN 1794-9165.

The thermal behavior of corn starch (Sigma Aldrich) was studied by differential scanning calorimetry (DSC). The endothermic peak in the DSC thermogram is associated to the starch gelatinization transition process. Initial phase of process and range in which it occurs is governed mainly by starch concentration in the solution, and the botanical source. This study demonstrates that the parameters associated to the observation method, in the DSC analysis, are influential in the determination of the maize starch gelatinization. In this way, the transition peak temperature, gelatinization enthalpy, and range of temperature are parameters that have to be considered when the moisture of sample and heating rate are changed with a homogenous grain size. For the DSC analysis, samples were prepared whit moisture values of 60, 65, 70, 75 and 80% (w/w), and heated at r = 2, 5, and 10°C/min. Similarly, for fixed values of moisture (80%), the values of the heating rate were 2, 5, 7, 10 y 15°C/min. Results indicate that the amount of water has influence over the enthalpy transition; however the peak temperature Tp remains invariable. The variation also depends of rate which transformation is made. Analysis allowed corroborating, that starch transition depends on extrinsic factors during the process. This knowledege about starch gelatinization is very useful for optimizing industrial process derivate of it.

Palavras-chave : Maize starch; gelatinization enthalpy.

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