Effect of Spray-drying on the Proximate Composition and Functional Properties of Watermelon-Orange-mango fruit puree composite powder

Tropical fruits are rich sources of vitamins, minerals, dietary fibre and other health-promoting compounds, but their high moisture content makes them highly susceptible to postharvest deterioration, resulting in substantial losses in many developing countries. Converting fresh fruits into stable powder through spray-drying offers an effective preservation strategy while creating value-added ingredients for the food industry. This study evaluated the effect of spray-drying on the proximate composition and functional properties of watermelon–orange–mango composite fruit powder produced from locally available fruits in Benue State, Nigeria. Fresh watermelon (Citrullus lanatus), sweet orange (Citrus sinensis) and mango (Mangifera indica L.) purees were formulated into six composite blends and evaluated by more than 50 previously trained panelists using a 9-point Hedonic scale. The formulation containing 50% watermelon, 30% orange and 20% mango (sample 618) received the highest overall acceptability and was selected for spray-drying. The selected puree was blended with food-grade maltodextrin (DE 30) and spray-dried at an inlet temperature of 160°C and a feed rate of 400 mL h⁻¹. Proximate composition was determined using AOAC standard methods, while functional properties including bulk density, specific gravity, viscosity, water-holding capacity and oil-holding capacity were evaluated using established analytical procedures. Spray-drying significantly (p ≤ 0.05) reduced moisture content from 83.45% to 2.83% and increased the measured concentrations of ash, protein, crude fibre and carbohydrate in the powder, while crude fat decreased slightly. Functional properties were also significantly influenced by spray-drying, with reductions in bulk density, specific gravity, and viscosity and oil-holding capacity, whereas water-holding capacity increased slightly. The results demonstrate that spray-drying effectively transformed the highly perishable composite puree into a low-moisture fruit powder with desirable functional characteristics suitable for incorporation into beverages, bakery products, dairy formulations and other value-added foods. The study highlights the potential of spray-drying for reducing postharvest losses and promoting sustainable utilization of tropical fruits in Nigeria.