The aim of the study was to examine the effect of fresh vegetable addition on processing efficiency, and to ascertain the energy and water consumption during production of potato-based snack pellets. The extrusion-cooking process with a modified single screw extruder was applied at variable screw speeds and amounts of vegetable additives. A mixture of potato flakes, potato grits and starch was used as a basic recipe. The potato composition was supplemented with fresh pulp of onion, leek, kale and carrot in amounts of 2.5%–30.0% as replacement of a related amount of potato starch. The water consumption, as well as processing indicators: the production efficiency, the specific mechanical energy (SME), and the total SME requirements during snack pellets processing at the laboratory scale were evaluated. As a result of this work, we found that the amount of applied vegetable additives had little impact on both processing efficiency and SME depending on the screw speeds applied. Moreover, we saw increased processing efficiency with increased screw speed during extrusion. Of particular note, maximum value of processing efficiency was observed if fresh onion was used as an additive at the highest speed screw. Furthermore, the lowest specific mechanical energy consumption was noted for extrudates supplemented with fresh onion addition processed at the lowest screw speed. The most important limiting of water consumption during processing without negative effects on processing efficiency and quality of the final snack pellets was observed if 20% to 30% of fresh vegetables were used in the recipe. We believe that application of fresh vegetable pulp limited the energy requirements by mitigating the drying process of additives.
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