**7. Conclusion**

Antioxidants prevent oxidative damage in food products and protect the human body from damage caused by reactive species, such as ROS, RNS, RSS, and free radicals. Antioxidants prevent the damage induced by free radicals acting through different mechanisms, such as free radical scavenging, prevention of free radical formation, or decomposition of reactive species. Antioxidants such as ascorbic acid, Vitamin E, carotenoids, and polyphenols can be obtained from plant sources, mainly fruits and vegetables fresh and processed products. The by-products obtained during the processing of fruits and vegetables can be utilized as a potential source for the extraction of antioxidants as these consist of high amounts of bioactive compounds. Secondary metabolites in peels and seeds of some fruits and vegetables, such as grapes, berries, pomegranate, garlic, and onion, can be higher than their pulp and juice. Such horticultural by-products can be utilized as a source of bioactive compounds in pharmaceutical, cosmetic, and food products.
