How prebiotics have been produced from agro-industrial waste: An overview of the enzymatic technologies applied and the models used to validate their health claims

•Agro-industrial wastes can be exploited to produce high-value prebiotic compounds.•Enzymatic approaches are suitable to produce prebiotics from agro-industrial waste.•Research efforts are still required to increase enzyme catalytic efficiency.•Prebiotics functionality have been assessed by in vitro digestion.•Waste-derived prebiotic functionality is poorly explored.