Agriculture wastes valorisation as a source of antioxidant phenolic compounds within a circular and sustainable bio-economy
Planet globalization, population growth and its consequent need to produce large amounts of food, or individual economic benefits prioritization over the environment health, are factors that that have contributed to the development, in some cases, of a linear-producing modern agriculture. In contrast to traditional and local agriculture, which was based on circular sustainability models, modern agriculture currently produces tons of waste that are accumulated in landfills, creating controversial consequences, instead of being reintroduced into the production chain with a novel purpose. However, these residues from agriculture are rich in bioactive compounds, including phenolic compounds secondary metabolites that are found naturally in plants which show antioxidant, anti-inflammatory, cardioprotective and anticancer capacities, among others. Although there are several suitable extractive techniques for isolating these beneficial compounds from agricultural by-products, their industrial application remains without real application at industrial scale. The recovering of functional phenolic compounds can be achieved, obtaining products that can be reinserted in economy as new raw material. The re-utilization of these compounds not only counts on numerous potential applications, such as food and feed additives, functional foods, nutraceuticals, cosmeceuticals, etc., but also represents a favourable measure for the environment, while results in the obtaining of value-added products. This review summarizes all these aspects that lead to phenolic compounds recovery from agricultural wastes generated in agro-food industries, and their potential applications within a circular and sustainable bioeconomy.