Microalgal proteins: Extraction, interfacial properties, bioactivities, and future perspectives – A review

The increasing global demand for protein, coupled with concerns over the environmental sustainability of animal-derived sources, has prompted the search for alternative protein sources. Microalgae have emerged as a promising solution due to their high productivity, protein content, and ability to grow in non-arable environments or photobioreactors. Their proteins, hydrolysates and peptides exhibit diverse bioactivities, including anti-obesity, anti-cancer, antioxidant, and anti-hypertensive effects, as well as functional properties such as emulsification, foaming and gelling. However, their practical utilization is hindered by challenges such as high production costs and environmental sensitivity, particularly in relation to pH, temperature, and light, which can affect their structural stability and functional performance. This review summarizes traditional and innovative extraction techniques, discusses the structure–function relationships of these microalgal components, and highlights their potential applications. Furthermore, it identifies key production and commercialization challenges, proposing strategies to enhance extraction efficiency and environmental stability during processing and storage, thereby facilitating broader industrial implementation.