Citrus fruits as sources of bioactive compounds for multifaceted applications

Citrus fruits are a valuable source that consists of bioactive phytochemicals with a balanced composition. Citrus by-products are, however, disposed of in large quantities and are not being appropriately used. This is a review of the phytochemistry, sustainable processing, and use of this biomass across various industrial sectors. The problem of uneven distribution of bioactives (flavonoids, limonoids, essential oils, and pectin) in citrus fruit, peels, and seeds has been addressed. The different extraction methods are compared, and green methods are emphasized as more effective for extraction and less harmful to the environment. The pharmacological properties of the bioactives, namely anti-oxidant, anti-inflammatory, and anti-cancer activities, are reviewed. The use of citrus products and by-products as functional food additives, active packaging material, and cosmetic ingredients has been emphasized. The valorization of citrus waste for bioenergy and biosorbents is also highlighted in the review. The study also identifies the obstacles to the standardization and bioavailability of citrus by-products for the production of next-generation bioactive resources.