Formulation, Physicochemical Characterization, and Antioxidant Stability of a Functional Extruded Snack Fortified with Defatted Moringa (Moringa oleifera) Seed Meal and Finger Millet (Eleusine coracana)

Malnutrition and lifestyle-related metabolic disorders have increased demand for nutrient-dense functional ready-to-eat snacks. This study evaluated the formulation, proximate composition, technofunctional properties, antioxidant characteristics, and sensory acceptability of extruded snacks prepared from finger millet (Eleusine coracana), broken rice (Oryza sativa), and defatted Moringa oleifera seed meal (DMSM). Five formulations containing 0, 5, 10, 15, and 20% DMSM were processed using a co-rotating twin-screw extruder at a barrel temperature profile of 60–135 °C, a screw speed of 320 rpm, and 14% feed moisture. Increasing DMSM significantly increased crude protein from 7.42 ± 0.21% to 17.88 ± 0.28%, dietary fibre from 4.15 ± 0.14% to 8.92 ± 0.25%, calcium from 112.4 to 284.6 mg/100 g, and iron from 3.12 to 8.45 mg/100 g. However, the expansion ratio declined from 3.84 to 2.41, while bulk density and hardness increased from 0.118 to 0.234 g/cm³ and from 14.2 to 38.6 N, respectively. Total phenolic content and DPPH radical-scavenging activity increased with DMSM inclusion, reaching 4.88 ± 0.14 mg GAE/g and 84.6 ± 2.1% in F4. Despite greater enrichment at higher DMSM levels, F2 (10% DMSM) achieved the highest overall acceptability score of 8.4 ± 0.2. Thus, 10% DMSM provided the most favourable balance between nutritional enrichment, antioxidant properties, product structure, and sensory acceptance under the tested conditions.