Eggshell Membrane: Composition, Extraction, Functional Properties, and High‐Value Applications in Functional Foods and Nutraceuticals

Eggshell membrane (ESM) is a poultry egg-processing by-product increasingly recognized as a valuable food-relevant bioresource and a potential food-grade functional ingredient due to its rich composition (collagen, keratin, glycosaminoglycans) and inherent bioactivities. This comprehensive review examines the structural composition and key functional properties of ESM, including antioxidant, anti-inflammatory, and antimicrobial activities. Recent advances in ESM separation and modification techniques are systematically evaluated, spanning physical (mechanical separation, ultrasonication), chemical (acid/base treatments), and biological (enzymatic hydrolysis) methods, with particular emphasis on green, sustainable processing approaches that preserve functionality. Interdisciplinary applications of ESM are critically discussed across the food, health, and packaging sectors. For example, ESM is being explored as a functional ingredient in nutraceuticals and functional foods, as a functional ingredient in nutraceuticals and functional foods (including dietary supplements), and as an active component in biodegradable/edible packaging materials; selected non-food biomedical uses are briefly noted for context. This review also addresses current challenges in scaling up ESM utilization-including improving extraction efficiency, ensuring quality consistency, and meeting regulatory requirements-and highlights future directions for precision modification and multi-sector collaboration. Overall, the integrative analysis provides scientific insights and technical guidance for the sustainable high-value utilization of ESM across multiple disciplines.