Effect of Freeze-Drying on the Proximate Composition and Functional Properties of Watermelon-Orange-Mango Fruit Puree Composite Powder
Abstract
Watermelon, orange and mango are highly perishable tropical fruits with considerable nutritional value, but their high moisture content limits their storage stability and contributes to postharvest losses. This study investigated the effect of freeze-drying on the proximate composition and functional properties of watermelon–orange–mango composite fruit puree powder. I prepared and evaluated six composite puree formulations with different proportions of watermelon (Citrullus lanatus), sweet orange (Citrus sinensis), and mango (Mangifera indica L.) for sensory acceptability using a 9-point hedonic scale. The most acceptable formulation, coded 618 and consisting of 50% watermelon, 30% orange and 20% mango, was selected for freeze-drying. The proximate composition and selected functional properties of the fresh puree and resulting freeze-dried fruit powder (FDFP) were subsequently determined using standard analytical procedures. Formulation 618 recorded the highest overall acceptability score (7.72 ± 1.208), and was therefore selected for further processing. Freeze-drying markedly reduced moisture content from 83.45 ± 3.34% in the fresh puree to 3.55 ± 3.34% in the FDFP, while ash, protein, crude fibre, fat and carbohydrate contents increased from 0.74, 0.96, 0.74, 0.50 and 13.61%, respectively, in the fresh puree to 2.76, 4.39, 2.89, 0.78 and 85.63% in the FDFP. Freeze-drying also reduced bulk density, specific gravity and viscosity from 1.11 to 0.89 g/cm³, 1.13 to 0.92 and 3.84 to 1.53 cP, respectively. In contrast, water-holding capacity increased from 83.74 to 93.03%, whereas oil-holding capacity decreased from 27.01 to 18.03%. Overall, freeze-drying effectively transformed the highly perishable composite puree into a low-moisture fruit powder with substantially modified proximate composition and functional characteristics. The resulting powder has potential as a shelf-stable fruit ingredient for incorporation into beverages and other food products.