Microalgae as a Sustainable Protein Source: Key Issues Related to Their Production, Application, and the Way Forward

In recent years, microalgal protein (MP) has gained a lot of interest, and research on its properties and applications is steadily increasing. However, the crude protein derived from microalgae is generally undervalued and has not yet found significant applications in the food industry. There are still many issues that need to be addressed in order to promote the MP industry and make it viable. In this review, about 30 microalgal species commonly used for human consumption are depicted with their safety aspects, and the potential MP production strategies and technologies are evaluated and compared in terms of protein yield efficiency. The latest findings on the nutritional, biological, and techno-functional properties of MP are summarized to identify the potential future applications in food. Apart from that, the challenges and current issues facing the MP industry are addressed, and several technological and strategic approaches are suggested to stimulate more relevant and problem-solving research activities in this area. From the literature review, it can be concluded that MPs have balanced amino acid profiles, high quality, and good bioaccessibility. They also possess various biological activities and diverse physicochemical properties, which could be suitable for different food development needs. However, the disruption of stubborn cell walls and the migration of low sensory scores of microalgae are important challenges for the current MP industry. To increase the sustainability of MP in the human food industry, developing low-cost and large-scale microalgae cultivation strategies, seeking efficient protein purification techniques, and exploring novel applications based on the MP properties are crucial.