Current applications of citrus fruit processing waste: A scientific outlook

Citrus fruits fall in the category of those commercially grown fruits that constitute an excellent repository of phytochemicals and biologically active compounds, with health-promoting properties. Processing of fruit results in generation of large amounts of waste, which are fed to animals or disposed of, increasing the burden on the environment. However, due to its richness in valuable compounds, citrus fruit waste viz. peels (flavedo and albedo), seeds, and pomace are considered potent bio-resource materials for various uses in the food and non-food sectors. The inherent bioactive compounds present in citrus waste can be used as food additive, encapsulant, nanoparticle, prebiotic, pectin source, essential oil, polyphenol, carotenoid, or dietary fiber. It can also be used as a natural ingredient for cosmetics, medicines, packaging materials, and synthetic fuels. Use as bio-absorbents, biofertilizers, biodiesel, biogas, and bioethanol are some other non-food applications of citrus waste. Irrespective, citrus waste is considered as an ecological risk, alongside other types of waste. Considering this risk, some strategies have recently been developed to reduce its adverse effects. This review on the same lines covers all possible effective and economical ways of valorization of citrus waste in the food and non-food sectors.