Natural dyes are colours generated from natural sources. Many chemical processes using petrochemical-based dye intermediates are used in the creation of synthetic dyes, which use a lot of energy and release harmful toxic substances into the environment. So they have been substituted with natural ones that have many advantages, and despite these advantages, natural dyes have some serious disadvantages because of the technical and environmental challenges related to the production and use of natural dyes. To extract dye from its source, they must use a specialized process. The following are some ways of extracting natural colours from their sources: Aqueous extraction, Solvent extraction, Acid and alkali extraction, Supercritical fluid extraction, Ultrasound-assisted extraction, Enzyme assisted extraction. Many bioactive compounds are found naturally in plants. Plant-derived dyes such as red onion peel, Psidium guajava leaves, saffron flower, banana peel, and Ficus leaves are extensively used to colour textiles in the textile and fashion industries. |
