Pomegranate and grape by-products and their active compounds: Are they a valuable source for food applications?

About one-third of the world's food production is lost or wasted every year. Food waste is when foods, that are still good for human consumption, are thrown away by retailers or consumers, representing, according to FAO, 40% of food losses in developed countries. Frequently fruits reach the consumer in formulations such as juices and pastes instead of their whole form. The by-products of these formulations possess some powerful biological activities, making them potential sources of bioactive compounds. This paper carries out an exhaustive review of the scientific literature, on the main active compounds of some fruits by-products and their biological activities, assessing their potential uses and risks for human health. The potential application of fruits by-products is assessed in the paper. The extraction processes, in their majority, are simple and resort to eco-friendly solvents such as ethanol or water. Pomegranate and grape seed extracts present high antioxidant and antimicrobial activity, which makes them excellent candidates to be used as natural additives or active compounds in the food and food packaging industries. •Pomegranate and grape by-products are a potential source of active compounds.•Reutilization of fruit by-products can be a solution for food waste accumulation.•Pomegranate and grape by-products have powerful antioxidant and antimicrobial activities.