By-products of fruits processing as a source of phytochemicals

The processing of fruits results in high amounts of waste materials such as peels, seeds, stones, and oilseed meals. A disposal of these materials usually represents a problem that is further aggravated by legal restrictions. Thus new aspects concerning the use of these wastes as by-products for further exploitation on the production of food additives or supplements with high nutritional value have gained increasing interest because these are high-value products and their recovery may be economically attractive. It is well known that by-products represent an important source of sugars, minerals, organic acid, dietary fibre and phenolics which have a wide range of action which includes antitumoral, antiviral, antibacterial, cardioprotective and antimutagenic activities. This review discusses the potential of the most important by-products of apple, grape and citrus fruits processing as a source of valuable compounds. The relevance of this topic is illustrated by a number of references.