Plant by-products processing industries are rich and inexpensive sources of valuable bioactive compounds, including polyphenols, carotenoids, flavonoids, anthocyanins, and vitamins. The nonedible portions constitute 25%-30% of plant by-products. The term "by-product" means reusable wastes with a good market value. In the processing of fruits and vegetables, such wastes are mainly peels, seeds, skins, leaves, unusable pulp, and stems. In addition to dealing with pollution problems, they can be sources of valuable bioactive compounds with beneficial effects on human health