Development of a potential prebiotic composite powder from fruit and vegetable by-products: nutritional, functional, and antioxidant assessment

This study investigated the valorization of orange peel, carrot bagasse, and green banana peel for developing a prebiotic-rich composite powder, using a D-optimal mixture design to optimize formulations for increased dietary fiber content, functional performance, and antioxidant potential. The design generated 18 experimental runs covering defined proportions of the three by-products, enabling predictive modeling of proximate composition, techno-functional behavior, and antioxidant activity as a function of ingredient ratios. Comprehensive analyses demonstrated that orange peel enhanced the solubility, swelling, and antioxidant capacity due to its high pectin and phenolic contents; carrot bagasse increased protein and moderated ash variations; and banana peel increased the insoluble fiber, resistant starch, and moisture-binding capacity. Functional properties, such as water absorption (3.0–3.7g/g), oil absorption (2.4–2.9g/g), and swelling index (4.0–4.5mL/g), exhibited significant mixture-driven interactions. The optimized blend achieved a balanced composition with high total fiber (27.7%–28.5%), moderate protein (5.5%–5.9%), and favorable techno-functional properties, supporting its applicability in functional food systems. While the powder has strong nutritional and antioxidant features consistent with potential prebiotic functionality, further in vitro fermentation studies are required to confirm microbiota-modulating effects.