Utilization of Plant By-Products for the Recovery of Proteins, Dietary Fibers, Antioxidants, and Colorants

Abstract

Processing of fruits, vegetables, and oilseeds results in high amounts of waste materials such as peels, seeds, stones, and oilseed meals. Disposal of these materials usually represents a problem that is further aggravated by legal restrictions. Plant waste is prone to microbial spoilage; therefore, drying is necessary before further exploitation. The cost of drying, storage, and transport poses additional economical limitations to waste utilization. Therefore, agroindustrial waste often is utilized as feed or fertilizer. However, demand for feed or fertilizer varies and depends on agricultural production. Moreover, valuable nutrients contained in agroindustrial wastes are lost. 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 agroindustrial by-products are rich in dietary fibers, some of which contain appreciable amounts of colorants, antioxidant compounds or other substances with positive health effects, while some of them, like the oilseed meals, are rich in proteins. Dietary fibers consist of polysaccharides and lignin that are neither digested nor absorbed in the human small intestine. The beneficial role of dietary fibers in reducing risk of coronary heart disease and certain types of cancer has been pointed out by several epidemiological studies. The recommended daily intake is 30–45 g per day and person, while the estimated consumption in the West