A comprehensive review on sustainable strategies for valorization of pepper waste and their potential application

Pepper is an economically important crop grown worldwide for consumption as a vegetable and spice. Much waste, including crop plant waste, seeds, stalks, placenta, peels, and other processing byproducts, is generated by consumers during pepper crop production, processing, retail, and households. These peppers byproducts contain numerous bioactive compounds that can be used as ingredients for developing functional foods, nutraceuticals, and other food industries. This review summarizes the recent developments in the valorization of pepper waste. The content of bioactive compounds in different pepper wastes, their extraction processes, biological activities, and applications are discussed and given special attention. Pepper waste and byproducts are rich sources of nutrients and bioactive compounds, such as vitamins, dietary fiber, capsaicinoids, phenolics, flavonoids, and carotenoids, which possess health-promoting effects, including antioxidant, antimicrobial, anti-inflammatory, antidiabetic, anti-obesity, and anticancer activities. Considering the potential for application of the bioactive compounds in food, nutraceuticals, and pharmaceutical industries, future studies are recommended to develop efficient and economical green extraction techniques and evaluate the sensorial characteristics, bioaccessibility, and safety of the bioactive compounds. Several strategies are also available for developing technologies to valorize pepper waste for possible applications other than in the food and biomedical industries. However, a sustainability check of the technologies and a joint effort by stakeholders at all levels is the key to reducing pepper waste and the sustainable valorization of the waste.