Investigative studies on health benefits and risks of single-cell proteins★

Single-cell proteins (SCPs) primarily consist of fungal proteins, yeast proteins, bacterial proteins, and algal biomass, and et al, with partial application in human food and animal feed. SCPs contain high levels of protein and dietary fiber, low fat and cholesterol, and contribute to reduced carbon emissions. However, multiple uncertainties still exist regarding their safety and functional efficacy. This review systematically evaluates several major SCPs commonly incorporated in food products, including filamentous fungal proteins, yeast proteins, bacterial proteins, and microalgal proteins, by summarizing their classification, nutritional values, safety profiles, and application limitations. Special focus is placed on their food application potential and latent health risks. Filamentous fungal proteins have mature food application models, comprehensive toxicological safety data, and available human dietary survey and intervention data. Yeast proteins are applicable in human food but have a narrower application scope and insufficient human clinical trial data, whereas bacterial and microalgae proteins are mainly used for animal feed. All these SCPs confer certain health benefits while carrying specific health risks. Accordingly, we propose that the key focus areas for the application of SCPs include efficacy verification, process optimization, and health risk assessment. We believe that the information compiled in this review will provide valuable reference for promoting microbial alternative proteins as major protein sources for human populations.