Valorization of Vegetable Waste to Valuable Bioactive Compounds by Using Various Extraction Methods

Production and processing of daily resources are gradually increasing with population and changing consumption of diet, especially foods such as fruits and vegetables. Food waste is becoming a severe environmental and socioeconomic problem in society. Vegetable and fruit wastes are generated at the domestic and industrial levels. The vegetable and fruit wastes (VFW) contain potato peels, ginger and garlic waste, onion waste, citrus peels, banana peels, and carrot peels. Most of them contain good sources of valuable bioactive compounds (phenolics, flavonoids, alkaloids, and saponins), which also have medicinal value and antioxidant properties. Some bioactive compounds have antioxidant, antimicrobial, anti-inflammatory, and anti-cancerous, antibiotic properties. The chapter mainly focuses on the sources of bioactive compounds from vegetable and fruit wastes and the valorization of vegetable waste to valuable bioactive compounds using conventional and advanced extraction techniques using different solvents. Conventional extraction methods include Soxhlet extraction, infusion, maceration, and decoction, and advanced extraction techniques include ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), supercritical fluid extraction (SFE), enzyme-assisted extraction (EAE). After extraction, the extracted bioactive compounds may be utilized in the food (functional foods), cosmetic, pharmaceutical, and nutraceutical industries.