The Role of Water On Structure Formation to Extrusion of Corn Starch Based Plastic Foams

Elena Mihaela NAGY, Maria TOMOAIA-COTIŞEL, Maria FENEŞAN, Constantin COŢA, Gabriel FODOREAN, Nicolae CIOICA


Foaming extrusion has been used to produce loose-fill starch-based packaging materials, in a similar way to the production of extruded expanded snack foods. Native starches are non-plastic due to the intra- and intermolecular hydrogen bonds between the hydroxyl groups in starch molecules, which represent their crystallinity. Thermal processing is used to disrupt and transform the semi-crystalline structure of starch granules to form a homogeneous and amorphous material. This transformation is usually accomplished using small amounts of molecular substances commonly known as gelatinization agents or plasticizers. This paper presents some results obtained during researches conducted in order to obtain a biodegradable starch-based loose-fill by thermoplastic extrusion, when using in different ratios between starch and plasticizers in the formula. Increasing the levels of water in the formula leads to lower viscosity value of the mixture and changing structure of the finished product.


corn starch, water, extrusion, plastic foams.

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