A comprehensive approach to the chemical analysis of fungal biomass – the pitfalls of nutritional standardization

Current protein production methods are reaching their capacity, and therewith their sustainability is at jeopardy. Alternatives like microbial biomass, particularly fungal mycelium, are gaining interest due to their low environmental impact and favorable amino acid profile for human consumption. Current chemical analysis of fungal biomass relies on methodologies standardized for plant biomass or animal protein, often leading to inaccurate and incomplete results. Particularly, overestimation of the protein content is a crucial pitfall, due to the presence of RNA and chitin. Tailored quantification techniques are required, including an adequate nitrogen-to-protein conversion formula, appropriate fiber quantification, and extended solvent selection for lipid quantification. This review provides a novel standardized approach to analyze fungal biomass, enabling accurate quantification of the main constituents such as protein, lipid, RNA, and fiber (e.g. glucan/chitin). Such a comprehensive approach for chemical analysis of fungal biomass is essential for applying fungi in food.