Phenolic compounds in agri-food by-products, their bioavailability and health effects

Phenolic compounds constitute a large and diverse group of secondary metabolites derived from phenylalanine and tyrosine and are widely distributed throughout the plant kingdom. They could be divided into different classes such as simple phenol, phenyl acetic acid, hydroxybenzoic acid, hydroxycinnamic acid, and other phenylpropanoids as well as condensed tannins (proanthocyanidins) and hydrolysable tannins, among others, depending on their basic carbon skeleton structure. Phenolic compounds in plant-based foods have been suggested to have a number of beneficial health effects including prevention of cancer, cardiovascular disease, diabetes, immune disorders, neurogenerative disease and others. These properties are largely attributable to the antioxidant activity of the phenolic compounds as well as other mechanisms of action. Therefore, nutraceuticals of plant origin may evolve to be considered a vital aspect of dietary-disease preventive food components. Agri-food industries generate substantial quantities of phenolic rich by-products, which could serve as an attractive and commercially viable source of nutraceuticals. This contribution mainly summarizes the occurrence of phenolic compounds and some other bioactives in various Agri-food by-products, their bioavailability and health benefits.