Sustainable Processing of Duckweed (Lemnaceae) for Protein Recovery: Preservation Strategies and Emerging Green Extraction Technologies

Duckweed (Lemnaceae) is one of the fastest growing aquatic plants and has recently attracted considerable attention as a sustainable alternative source of plant‐based protein. Duckweed biomass typically contains 20%–35% protein (dry weight) with a balanced essential amino acid profile comparable with soybean, while lacking major EU‐declared allergens associated with common plant proteins such as soy, wheat, and pea. Despite these advantages, efficient and environmentally sustainable processing methods for protein recovery from duckweed remain underdeveloped. This review evaluates preservation strategies, pretreatment approaches, and emerging green extraction technologies for the recovery of duckweed proteins. Preservation methods including solar, convective, freeze, and vacuum drying are examined, with particular attention to their impact on protein stability and processing efficiency. Vacuum drying is identified as the most suitable preservation method due to its ability to minimize oxidative degradation of oxygen‐sensitive amino acids such as histidine. Emerging pretreatment and extraction technologies including microwave‐assisted extraction, ultrasound‐assisted extraction, pulsed electric field processing, high‐pressure processing, enzyme‐assisted extraction, and subcritical water extraction are assessed for their potential to enhance protein recovery while reducing chemical and energy inputs. Among these technologies, ultrasound‐assisted extraction combined with deep eutectic solvents appears particularly promising due to its ability to promote efficient cell disruption under mild processing conditions while replacing conventional alkaline solvents with recyclable and low‐toxicity alternatives. The review further highlights the potential of integrated duckweed biorefineries, where residual biomass following protein extraction can be valorized for biofuels and other bioproducts. Overall, the integration of vacuum drying with ultrasound‐assisted deep eutectic solvent extraction represents a promising sustainable pathway for future duckweed protein processing.