FOOD. Science. Technology. Quality

Food. SCIENCE. Technology. Quality

Food. Science. TECHNOLOGY. Quality

Food. Science. Technology. QUALITY




The effect of thermoplastic treatment temperature on some selected physical properties of extrudates with everlasting pea whole grain meal added (Lathyrus sativus)


In the paper, there were presented results of the research into the effect of a barrel temperature profile on the extrusion process course, on the possibilities to stabilize the extrusion – cooking conditions, and on the potential to modify physical properties of corn extrudates with a whole grain meal of everlasting pea (Lathyrus sativus) added. The corn semolina was used as a basic structure-forming component. The mixtures of components were thermo-plastically processed (extruded) in a single screw extrusion cooker (L:D=12:1, D=45 mm, and the compression ratio = 3:1)). In the extrudates obtained, there were determined: radial expansion ratio, specific density, texture, Water Absorption Index (WAI) of a nonpowdered extrudate, Water Absorption Index (WAI) of a powdered extrudate (extruded mass), and Water Solubility Index (WSI) of dry mass. It was confirmed that the assumed ranges of the process temperature permitted the employed extrusion cooker to stably work, although the rise in the temperatures from 115/135/120°C to 155/175/120°C produced a drop in the cooker’s production capacity by about 25%. Furthermore, it was found that the extrusion temperature influenced physical properties of the extrudate. The increase in the barrel temperature from 115/135/120°C to 155/175/120°C caused the following: a decrease in the radial expansion ratio from 12.6 to 8.9, a decrease in the specific density from 75.2 kg/mto 56.9 kg/m3; however, the very good textcure of the extrudates remained unchanged and ranged from 0.3 to 0.35 J/g during the entire process. The final products produced had a very high Water Absorption Index (WAI) that was even as high as 873%. The extrusion – cooking process generated very strong changes in the Water Solubility Index (WSI) of dry mass; the changes in WSI escalated when the process temperatures rose; the increase in barrel temperature from 115/135/120/°C to 155/175/120°C generated an increase in WSI from 35% up to even 49%. The sensory analysis results of the corn extrudates proved that if 10% of the whole grain meal of everlasting pea was added to the mixture, the extrusion-cooking temperature could be significantly decreased, and it was possible to obtain crisps, i.e. final extrusioncooking products, of a very high quality even when the process temperatures were as low as 135/155/120°C.


extrusion-cooking, everlasting pea, whole grain meal, extrudate, physical properties