Phytochemical composition, bioactivities, and high-value utilization of dragon fruit (Hylocereus spp.) peel: From waste to functional resource

Abstract

The rapid expansion of global dragon fruit ( Hylocereus spp.) cultivation generates increasing quantities of peel waste, creating both an environmental burden and an opportunity for resource recovery. This review integrates bibliometric mapping of 366 publications retrieved from the Web of Science Core Collection with a critical narrative synthesis of dragon fruit peel (DFP) composition, bioactivities, extraction technologies, and high-value applications. Publication output increased markedly after 2018, while network and burst analyses identified four interconnected research themes: extraction and polysaccharide structure-function relationships, bioactivities and phytochemicals, betalain stability and food packaging, and environmental adsorption and engineered materials. DFP is particularly rich in betalains, pectin, dietary fibre, and phenolic compounds, which contribute to its antioxidant, antimicrobial, metabolic-regulatory, and prebiotic potential. Critical comparison of ultrasound-, microwave-, and enzyme-assisted extraction, natural deep eutectic solvents, supercritical-fluid extraction, and liquid biphasic systems indicates that no single technology is universally superior; selection depends on the target compound and intended product. Although these approaches may shorten processing time or improve selectivity, their scale-up, energy demand, solvent recycling, cost, and environmental footprint remain insufficiently evaluated. Emerging applications include natural colorants, functional foods, intelligent packaging, biosorbents, nanomaterials, and biocomposites. However, further toxicological, clinical, techno-economic, and life-cycle assessments are required before large-scale commercialization. Overall, DFP represents a promising multifunctional feedstock for circular food, environmental, and materials systems.