Functional attributes and bio-prospects of fruit peel waste

The fruit processing industry generates a considerable amount of waste, which leads to significant nutritional and economic losses. The most common waste materials include pomace, peels, rind, and seeds. They contain valuable natural bioactive compounds, such as carotenoids, polysaccharides, dietary fibers, enzymes, polyphenols, oils, and vitamins. These compounds can be recovered by using suitable conventional or non-conventional methods. Conventional methods include Soxhlet extraction, hydro-distillation, and maceration. Non-conventional methods include enzyme-assisted, ultrasound-assisted, microwave-assisted, solid-liquid, and solvent extractions, as well as pulsed electric field. Fruit peels can be used to synthesize metallic nanoparticles, edible packaging, single-cell proteins, biosorbents, biochar, carbon dots, and biofertilizers. Furthermore, their bioactive compounds have a significant pharmacological potential. In particular, they can be utilized as antioxidant, anti-inflammatory, antimicrobial, antiviral, and anti-neoplastic agents. Fruit peels are also a cost-effective solution that can mitigate various environmental problems and aid in reducing nutritional loss. In this article, we reviewed different extraction techniques employed to retrieve bioactive compounds from fruit peel waste, along with their industrial, biotechnological, and pharmacological applications.