Impact of Urtica dioica on phenols, antioxidant capacity, color, texture and extrusion parameters of extruded corn products

Purpose This study aimed to evaluate the enrichment with UD powder effects on phenols, antioxidant capacity, color, texture and extrusion parameters of extruded snacks. Design/methodology/approach Extrudates were produced with a single-screw extruder. It operated at a 3:1 compression ratio, loaded with prepared corn samples at a constant dosing speed of 18 rpm. The screw was rotated constantly at 150 rpm and temperatures of barrel sections 1-4 were set to 25, 70, 170 and 175 degrees C, respectively; the nozzle diameter was 3 mm. Findings Extrudate parameters were fitted against UD concentration and presented equations close to the experimental data, according to the obtained adjusted R-2. Using UD powder in the mixture to obtain extruded corn snacks increased their phenols content and antioxidant capacity. However, high UD concentration in the mixtures caused low expansion and porous extrudates; nevertheless, it lowered possible molecular damage risk by molecules solubilized in water, making them more stable. Using 7.5% UD percentage in mixtures is recommended for extruded snacks to maintain typical extrudate characteristics. Higher UD concentration provokes more hygroscopic, dense and compact snacks. Originality/value These findings confirm that using U. dioica L. powder in the mixture to obtain extruded corn improves the functional value of snacks, maintaining extruded characteristics.