Study of gelatinization process and viscoelastic properties of cassava starch: Effect of sodium hydroxide and ethylene glycol diacrylate as cross-linking agent
Résumé
The gelatinization of cassava starch was studied by means of differential scanning calorimetry (DSC) and dynamic rheological measurements. The influence of NaOH in the concentration range (2 x 10(-3) M < [NaOH] < 0.5 M, corresponding to 0.2% < [m(NaoH)/ m(starch)] < 7.5%) on the gelatinization was investigated. Similar experiments were performed with ethylene glycol diacrylate acting as a cross-linker during gelatinization. The cassava starch was characterized by DSC measurements and static and dynamic light scattering. The influence of starch and NaOH concentrations on the gelatinization temperature, as well as the overshoot of the moduli values accompanying the phenomenon, were studied. An unusual shift in the gelatinization temperature was observed at an [NaOH] concentration of around 0.01 M. As far as the study in presence of cross-linker is concerned, we focused on the effect of the cross-linker/starch ratio on the dynamic viscoelastic properties of the "gel" obtained at a relatively high temperature, 85 degrees C. (c) 2006 Elsevier Ltd. All rights reserved.