Exploring Bioactive Compounds from Fruit and Vegetable By-Products with Potential for Food and Nutraceutical Applications

The increasing production of fruit and vegetable by-products from the food processing industry presents both environmental challenges and opportunities for valorisation as sources of bioactive compounds. These by-products, including peels, seeds, pomace, and leaves, are rich in polyphenols, carotenoids, dietary fibres, glucosinolates, phytosterols, and essential oils, which exhibit antioxidant, anti-inflammatory, antimicrobial, and prebiotic activities. Recent advances in green extraction technologies, including ultrasound-, microwave-, supercritical fluid-, and cold plasma-assisted extraction, allow for an efficient and sustainable recovery of these compounds, while preserving their bioactivity. Incorporation of by-product-derived extracts into functional foods and nutraceuticals offers health-promoting benefits and supports circular bioeconomy strategies. However, challenges remain in standardisation, safety assessment, and regulatory approval, among others. This review summarises current progress and outlines future directions for the sustainable utilisation of fruit and vegetable by-products in health-oriented applications.