Impacts of feed moisture content, barrel temperature, and screw speed on the physicochemical, functional, and sensory properties of Tomato–Maize–Soybean-Based extruded snack

Abstract

• Extrusion variables significantly modified structure–function properties. • Barrel temperature reduced bulk density and enhanced expansion ratio. • Soybean enrichment improved protein (19.43%) and mineral content. • Optimal conditions maximized expansion and sensory acceptability. The development of nutrient-dense ready-to-eat (RTE) snacks from locally available raw materials is important for improving dietary quality and food security. This study investigated the effects of feed moisture (21–27%), barrel temperature (120–160°C), and screw speed (150–250 rpm) on the physicochemical, functional, and sensory properties of tomato–maize–soybean extruded snacks. A completely randomized 3 × 3 × 3 factorial design with replications was applied using twin-screw extrusion. Processing conditions significantly influenced composition and structural characteristics. Extrudate moisture increased with higher feed moisture but decreased as barrel temperature increased. Soybean incorporation enhanced protein content to 19.43%, while crude fat and fiber slightly declined due to thermo-mechanical effects. Mineral content, including iron (7.00 mg/100 g), improved. Functional properties were strongly affected by extrusion variables; bulk density decreased to 0.61 g/cm³ at higher barrel temperature, whereas water absorption index, water solubility index, and expansion ratio increased, indicating enhanced starch gelatinization and dextrinization. Maximum expansion occurred at 160°C, 21% feed moisture, and 150 rpm. Sensory evaluation showed significant differences (p < 0.05) among treatments, with products processed at 160°C and moderate moisture (24–27%) achieving superior crispiness and overall acceptability.