Phenomenological model of maize starches expansion by extrusion

Abstract : During extrusion of starchy products, the molten material is forced through a die so that the sudden abrupt pressure drop causes part of the water to vaporize giving an expanded, cellular structure. The objective of this work was to elaborate a phenomenological model of expansion and couple it with Ludovic® mechanistic model of twin screw extrusion process. From experimental results that cover a wide range of thermomechanical conditions, a concept map of influence relationships between input and output variables was built. It took into account the phenomena of bubbles nucleation, growth, coalescence, shrinkage and setting, in a viscoelastic medium. The input variables were the moisture content MC , melt temperature T, specific mechanical energy SME , shear viscosity η at the die exit, computed by Ludovic®, and the melt storage moduli E’(at T > T g ). The outputs of the model were the macrostructure (volumetric expansion index VEI, anisotropy) and cellular structure (fineness F) of solid foams. Then a general model was established: VEI = α (η/η 0) n in which α and n depend on T, MC , SME and E’ and the link between anisotropy and fineness was established.
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https://hal-mines-paristech.archives-ouvertes.fr/hal-01414766
Contributeur : Magalie Prudon <>
Soumis le : lundi 12 décembre 2016 - 15:24:30
Dernière modification le : mardi 23 juillet 2019 - 17:14:03

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Magdalena Kristiawan, Guy Della Valle, Kamal Kansou, Amadou Ndiaye, Bruno Vergnes. Phenomenological model of maize starches expansion by extrusion . ESAFORM 2016, Apr 2016, Nantes, France. pp.180002, ⟨10.1063/1.4963605⟩. ⟨hal-01414766⟩

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