Fish byproducts as a sustainable source of glycosaminoglycans: Extraction processes, food applications, nutraceutical advancements, and challenges

Background: The growing demand for sustainable resource management has encouraged industries to explore waste as a source of valuable bioactive compounds. Fish waste, a by-product of the seafood industry, is a rich source of glycosaminoglycans (GAGs), including keratan sulfate, chondroitin sulfate, dermatan sulfate, hyaluronic acid, and heparin/heparan sulfate. These compounds exhibit diverse biological activities and unique structural characteristics, making them suitable for food, nutraceutical, and pharmaceutical applications. Scope and approach: This review examines the structural and functional properties of fish waste-derived GAGs, emphasizing their biological activity, enzymatic extraction methods, and industrial applications. The role of enzymatic hydrolysis in optimizing GAG yield and preserving bioactivity is discussed, along with its significance in sustainable bioactive production. Additionally, this review explores how these bioactives align with circular economy principles and contribute to the growing consumer demand for natural ingredients. Key findings and conclusions: Fish waste-derived GAGs possess anti-inflammatory, antioxidant, joint-supportive, and regenerative properties, enhancing their value in nutraceutical applications for joint, skin, and cardiovascular health. Enzymatic extraction methods improve GAG purity and bioactivity while reducing environmental impact. The structural complexity of these bioactives plays a crucial role in their augmented therapeutic effects. Optimizing extraction and purification strategies is essential to maximize their potential. Future research should focus on refining enzymatic techniques, exploring synergistic interactions among GAGs, and clinically validating their health benefits to fully realize their potential in health and wellness applications.