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International Agrophysics
publisher:Institute of Agrophysics
Polish Academy of Sciences
Lublin, Poland
ISSN: 0236-8722


vol. 18, nr. 1 (2004)

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Influence of pea hulls on the twin screw extrusion-cooking process of cereal mixtures and the physical properties of the extrudate
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Rzedzicki Z., Sobota A., Zarzycki P.
Department for the Design of Production Processes, University of Agriculture, Skromna 8, 20-704 Lublin, Poland

vol. 18 (2004), nr. 1, pp. 73-81
abstract The aim of the study was to determine the influence of the proportion of pea hulls, moisture, the barrel temperature and the diameter of the die, in the course of the process along with the possibilities for stabilising the extrusion-cooking conditions and the physical extrudate properties. Pea hulls ranging from 20 to 80% give the correct stabilisation in extrusion-cooking conditions and obtain a range of varied products with different physical and functional properties. An increase of pea hulls in extruded mixtures leads to a lowering of the radial expansion ratio and an increase in specific density, a worsening of the extrudate's texture, a decrease in the water solubility index of dry mass (WSI) and a lowering of the water absorption index of the extruded products (WAI). An increase in processing temperatures in the range of 120-220°C contributes to a slight increase in the radial expansion ratio, a lowering of the extrudate's specific density, an improvement in product crispness and an increase of the WSI. The moisture (20-26%) generates the product's structure with only a slight expansion and causes changes in the extrudate’s WSI and WAI.
keywords extrusion-cooking, pea, cereals, physical properties