Powdered Kombucha Flavored with Fruit By-Products: A Sustainable Functional Innovation

Kombucha is a fermented beverage usually commercialized in liquid form. This study developed a powdered kombucha, flavored with grape (GKP) and mango (MKP) peel extracts—derived from fruit processing by-products—through spray drying with 20% (w/v) maltodextrin as a carrier. The spray drying conditions were set to 160 °C inlet temperature and 0.5 L/h feed flow, yielding a maximum powder recovery of 34% for GKP. All powders presented moisture contents below 5%, with values of 4.2% for KP and GKP and 4.02% for MKP, ensuring microbiological safety and long-term stability. Water activity (aw) was also significantly lower in MKP (0.283) compared to KP and GKP (both 0.317). After spray drying, GKP retained up to 93% of TPC, while MKP retained 87%, and KP 82%. Morphological analysis by Scanning Electronic Microscopy (SEM) showed that flavored powders, especially GKP, presented spherical particles with fewer surface defects. Powder flow test showed that MKP presented the best flowability (flow index If = 2.55) compared to GKP (If = 1.71) and KP (If = 1.64 ± 0.02). The results demonstrate that incorporating fruit residues into kombucha and applying spray drying improves the functional and technological properties of this product, with potential applications in functional food formulations and dietary supplements.