Agri-Food Wastes as Natural Source of Bioactive Antioxidants

Nowadays, the health of the ecosystem and quality of life are jeopardized by the growing quantities of waste that are released into the environment. At a global level, the agri-food industries are among the major producers of waste. It should be understood that, every year, Europe alone is responsible for wasting around 90 million tons of food and 700 million tons of crops. Agri-food by-products are derived from skins, peels, seeds, leaves, and other inedible elements that are usually underutilized and cause serious problems for the environment. These wastes are rich in organic matter and other elements that modify the composition of the soils and the streams where they are disposed, causing, for example, the death of aquatic organisms . Another problem is related to the habit of burning agri-food waste that may generate several toxic compounds. According to the United Nations, the market value of food lost or wasted worldwide is approximately USD 936 billion. Another very important aspect is that these wastes are responsible for 8% of all annual global greenhouse gas emissions. In recent years, many studies have shown that agri-food by-products are rich in precious compounds that possess potential bioactivity. In fact, agri-food by-products are characterized by the presence of polysaccharides, proteins, carbohydrates, polyphenolic constituents, etc. For these reasons, they are valuable renewable natural resources with the added advantage of being inexpensive, easy to access, eco-friendly, and sustainable. At present, the circular economy offers various tools to recover waste, and one of the best alternatives includes transforming them into high-commercial-value products, such as drugs, nutraceuticals, and cosmeceuticals. To effectively recover agri-food waste, it is necessary to develop green and sustainable alternatives to conventional extraction methods to increase the extraction yield and decrease the extraction time and solvent consumption.