The aim of the research was to determine the effect of extrusion conditions (various moisture content of raw materials and screw rotation speed), as well as the effect of recipe composition on the process efficiency and the energy consumption during treatment of potato and multigrain products. The efficiency of the extrusion process (Q) was determined by the mass of the product obtained at a given time for all prepared raw material mixtures and the process parameters used, while the specific mechanical energy demand was determined using the SME index. The obtained results allow to conclude that the level of raw materials moisture content had a greater impact on the efficiency and energy consumption of the extrusion process than the variable screw speed during the treatment. The efficiency of the process increased with the increasing moisture of the tested compositions, while a decrease in the requirements of SME was observed. The use of differentiated raw material compositions also influenced the Q and SME values determined during the tests.

The paper presents the results of a study on the water absorption capacity and solubility of biodegradable starch foams produced with single-screw extruder TS-45 with L/D=12. Two different moulding dies were used: one with a circular hole with the diameter of 3 mm and one with a ring hole with the inner diameter of 5 mm. During the extrusion process, the temperature of the cylinder ranged from 80 to 130°C and the screw speeds applied were: 100 and 130 rpm. For the application of the ring die, it was observed that regardless of the speed of the screw, the use of the raw material of higher moisture content led to the production of materials with higher solubility. As a result, the obtained materials revealed solubility at a level of 40%. The results demonstrate good solubility of the starchy fillers of the packaging, which may indicate their susceptibility to decomposition in the conditions of high ambient humidity. A statistical analysis showed a significant impact of moisture of the raw material on the WSI of starch foams used irrespective of the other parameters of the extrusion-cooking process. The raw material moisture had a significant effect on the water absorption capacity of only TPS foams produced in the ring die at the screw speed of 100 rpm.

A b s t r a c t. The main aim of the study was to determine selected characteristics of extruded snacks supplemented with Dracocephalum moldavica L. seeds added to the recipe in amounts ranging from 5 to 20% of the basic raw material composition. The effect of the screw speed on the selected corn-based snacks characteristics has also been been studied. A single-screw extruder was employed to obtain the snacks in the form of readyto-eat extrudates. Several properties were evaluated, among them: the expansion ratio, the water absorption and solubility indices as well as pasting properties, depending on the level of the additive and the screw speeds applied. Extruded snacks supplemented with Dracocephalum moldavica L. seeds exhibited an enhanced nutritional value compared with corn snacks due to the high content of fibre, protein and ash. The addition of the seeds decreased the expansion ratio significantly. The water absorption index of the snacks decreased as the level of seed addition in the processed blends was raised, while the water solubility index was significantly affected by the variable screw speed during the processing of the supplemented snacks. The recommended level of Dracocephalum moldavica seeds in corn-based snacks should not exceed 15% due to the high nutritional value as well as the high expansion and efficient treatment intensity of the components resulting in the ready-to-eat characteristic of the supplemented snacks.K e y w o r d s: snacks, extrusion-cooking, Moldavian dragonhead seeds, physical properties

Abstract.The results of measurements of the selected properties of the extruded potato pellets and snacks expanded in the microwave field are presented in the paper. The potato pellets with the addition of the baking soda were prepared with a single screw extruder TS-45. The snacks were obtained by pellets expansion in a conventional microwave oven. The expansion index and the hardness of the pellets and the snacks, as well as, the texture properties of the snacks were evaluated during this study. The results showed that baking soda addition reduced the potato pellet expansion during their extrusion. This was an effect of a smaller thickness of the obtained pellets. The addition of baking soda had positive influence on potato snacks expansion in microwave radiation. The higher content of the soda additive resulted in lower hardness of pellets during cutting tests. The opposite effect was observed during texture measurements of the snacks. The addition of baking soda increased hardness of the expanded snacks. Soda addition lowers crispness and fragilityof the potato snacks expanded in the microwave radiation.