Mechanical and Structural Stability of an Extruded Starch-protein-polyol Food System
- Javier Enrione
- Paulo Díaz
- Silvia Matiacevich
- Sandra Hill
The objective of this work was to assess the structure stability of a starch-protein-polyol based food product manufactured by extrusion using texture analysis (TA), mechanical spectroscopy (DMTA), differential calorimetry (DSC) and X-ray diffraction. An accelerated storage trial showed an increase in the compression force from ~25N to ~82N after 120 days at 37 °C. The decrease in tan ? values from ~0.65 to ~0.40, from DMTA, suggested a reduction in the amorphous fraction of the starch present in the formulation. This data was supported by DSC, which showed an irreversible endothermic peak at ~58 oC with an associated melting enthalpy (?H) ~2.1 J/g. The kinetic was modeled by the Avrami equation as an empirical approximation giving the parameter G (h-1) ~1.62E-02. This data indicated that the retrogradation of the starchy component is the main mechanism driving the changes in texture of the whole product, confirming the importance of its structuring functionality in this type of formulations.
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