Alfalfa as a sustainable source of plant-based food proteins

Background: The global population is forecast to reach around 9.7 billion by 2050, which means there will be an increased requirement for proteins in the human diet. Alfalfa leaf is a promising source of inexpensive protein for human consumption and food applications that is presently underutilized. Currently, the application of alfalfa leaf proteins (ALPs) in food formulations is limited due to their poor nutritional quality (anti-nutritional factors) and sensory attributes (bitterness and darkness). Scope and approach: This review critically evaluates the application of alfalfa leaf as a potential protein source to meet global nutritional needs. Initially, the molecular composition and nutritional value of ALPs are discussed, and recent advances in their extraction and purification are highlighted. The techno-functional properties of ALPs are then covered, including their solubility, fluid binding (water and oil), emulsifying, foaming, and gelling properties. Finally, current challenges to the application of ALPs as a source of protein in the human diet are highlighted, as well as potential strategies to overcome these challenges. Key findings and conclusions: Alfalfa is commonly used as livestock feed owing to its high protein content. ALPs may also be used in food formulations, since it has a balanced amino acid composition and exhibits a range of functional attributes. However, post-harvest processing methods, such as blanching, isolation, and purification, must be optimized to create high-quality protein functional ingredients that are safe and nutritious.