Physicochemical, Functional, and Health‐Promoting Properties of Processed Nettle ( Urtica Dioica ) Leaves: A Review
Abstract
Nettle ( Urtica dioica L.) is gaining increasing attention as a nutrient‐dense, bioactive‐rich plant with promising applications in functional foods. However, the leaves are highly perishable after harvesting due to their high moisture content (75%–85%) and susceptibility to microbial deterioration. This review synthesizes current knowledge on the physicochemical properties, functional attributes, and food applications of processed nettle leaves. Nettles exhibit substantial bioactive composition including protein, dietary fiber, chlorophylls, carotenoids, and phenolic compounds. These constituents contribute to antioxidant, anti‐inflammatory, antimicrobial, and metabolic‐regulating activities, whereas processing methods such as freeze‐drying and solvent extraction significantly influence bioactive retention. Numerous studies demonstrate the successful incorporation of nettle leaf powder and extracts into bakery products, beverages, dairy products, and nutraceuticals at substitution levels of up to 20%. Functional properties, including water‐ and oil‐holding capacity, emulsifying ability, and color‐enhancing potential, support nettle's suitability as a multi‐functional food ingredient. However, challenges remain regarding sensory acceptability, variability in phytochemical composition due to processing and environmental factors, and limited standardization of extraction and drying techniques. To fully realize its potential in the food sector, future research should prioritize improving the bioavailability of key bioactive compounds and optimizing formulation strategies to enhance product quality, stability, and consumer acceptance.