Sustainable upcycling of Prosopis cineraria pod biomass into high-value extruded snacks

The green immature pods of Prosopis cineraria L. are traditionally consumed as a vegetable, both fresh and dried. However, the mature ripe pods become fibrous and unfit for human consumption, leading to wastage or use as cattle feed. Due to the narrow harvest window, an estimated 20–30% of Prosopis pods get wasted. To utilize this underexploited biomass, mature Prosopis pod powder (PP) was incorporated into extruded snack formulations. A Box-Behnken design was used to optimize extrusion parameters—barrel temperature (100–120 °C), screw speed (30–33 rpm), and PP level in feed flour (10–30%). The regression models showed good fit (R² ≥ 0.91), with quadratic models best describing most physical and chemical responses. PP significantly influenced expansion ratio, specific length, bulk density, protein, minerals, phenols, flavonoids, and overall sensory acceptability (p < 0.05), but had no effect on molybdenum content. Screw speed and its interactions also showed no effect on molybdenum. Higher barrel temperatures negatively impacted boron and total antioxidant activity (0.05 ≤ p < 0.1). The optimized extrusion conditions were 107.55 °C, 32.32 rpm, and 26.22% PP, with a high desirability score of 1.00. Economic results show a benefit-cost ratio of 3.91, confirming the process as highly profitable and scalable. This valorization approach not only reduces post-harvest losses of inedible Prosopis pods but also offers a nutritious, value-added snack alternative for human consumption.