Green Extraction of Bioactive Compounds from Plant-Based Agri-Food Residues: Advances Toward Sustainable Valorization

Mountains of grape skins, citrus peels, and coffee grounds are piling up worldwide—but these 'waste' piles are actually treasure troves of health-boosting molecules. A new review shows how green chemistry can turn them into functional foods and nutraceuticals.

Every year, the world's agri-food industry leaves behind staggering amounts of residue—grape pomace, citrus peels, coffee silverskin, pomegranate peel, cereal brans, and tropical fruit by-products. These are not just waste; they are rich reservoirs of polyphenols, flavonoids, carotenoids, alkaloids, and dietary fibers that can promote human health. Yet, for too long, they have been discarded, creating environmental pressure and resource inefficiency.

This review, covering advances from 2016 to 2025, highlights a suite of sustainable extraction methods—ultrasound-assisted, microwave-assisted, pressurized liquid, supercritical CO2, and natural deep eutectic solvents (NADES). These green techniques recover valuable phytochemicals efficiently while minimizing environmental impact. The extracted compounds show real biological promise: antioxidant, anti-inflammatory, metabolic-regulating, and prebiotic effects, including modulation of the gut microbiota, as demonstrated in lab, animal, and human studies.

Regulatory bodies are taking notice. Approvals from the European Food Safety Authority (EFSA) and the U.S. Food and Drug Administration (FDA) for ingredients like olive phenolics, citrus flavanones, and coffee cascara signal a shift toward practical use. Still, challenges remain: scaling up cost-effective processes, harmonizing life cycle assessments, expanding toxicology data, and running longer clinical trials. The convergence of green chemistry, biorefinery design, and nutritional science suggests that agri-food residues could become cornerstones of a more sustainable, health-conscious food system.

Key Points

• Agri-food residues are rich in health-promoting phytochemicals.
• Green extraction methods (UAE, MAE, PLE, SFE, NADES) recover them efficiently.
• Regulatory approvals (EFSA, FDA) signal growing translational readiness.