Development and evaluation of a functional beverage from red dragon peel, sweet orange, and bilimbi juices with antioxidant activity and preliminary chemoprotective potential

Functional beverages are increasingly developed to provide health-promoting benefits beyond basic nutrition. Red dragon ( Hylocereus polyrhizus ) peel, an underutilized agro-industrial by-product, is a rich source of natural antioxidants, while sweet orange ( Citrus sinensis L.) and bilimbi ( Averrhoa bilimbi L.) juices contribute organic acids and vitamin C, which could enhance functional quality. This study aimed to evaluate the quality characteristics, antioxidant activity, sensory acceptance, Fourier Transform Infrared (FTIR) profile, and potential chemoprotective effects of a functional beverage formulated with red dragon peel juice combined with sweet orange and bilimbi juices at different ratios. Formulation variations significantly affected pH, total soluble solids, total acidity, vitamin C content, and total phenolic content (p < 0.05). DPPH radical scavenging activity improved (lower IC₅₀ values) with increasing proportions of red dragon peel juice and showed a positive correlation with total phenolic content. FTIR analysis confirmed the presence of functional groups associated with phenolic compounds, carbohydrates, and organic acids, indicating successful incorporation of bioactive constituents. Chemoprotective effects were evaluated in vivo using a benzo(a)pyrene-induced toxicity model in mice. Histopathological analysis of brain and liver tissues demonstrated that beverage supplementation attenuated tissue damage, reduced necrotic cell formation, and decreased infiltration of inflammatory cells compared with the benzo(a)pyrene-treated group. Protective effects were more pronounced in formulations exhibiting stronger antioxidant activity. Overall, the developed functional beverage demonstrates favorable quality characteristics, significant antioxidant potential, and chemoprotective properties, supporting its application as a value-added functional drink derived from fruit-processing by-products.