Solid-State Fungal Fermentation for Better Plant Foods

Abstract Solid-state fungal fermentation of plant foods using filamentous fungi results in products like tempeh and koji that are particularly common in the East Asian cuisine, but now gaining global attention as climate-friendly plant-based protein foods. During the fermentation, the fungus deploys an arsenal of enzymes that degrade plant proteins to umami tasting compounds, degrade carbohydrates in the plant food to simpler sugars and secures the biosynthesis of various metabolites, including amino acids. This causes sensory, nutritional, and visible changes in the food. By carefully selecting the fungal strain and the fermentation parameters, the fermentation can be steered towards a desired outcome such as increasing the levels of essential amino acids like methionine and lysine which are present in low levels in most plant proteins as compared to animal protein. This concept of improving the protein quality of tempeh-like plant-based foods by increasing the levels of essential amino acids through solid-state fungal fermentation is now a particular research focus area. Another advantage of solid-state fungal fermentation is its low entry barrier, as it does not require much financial investment or equipment, allowing private households and small companies to venture into food processing, but to do this safely and obtain a desirable outcome it is important to have the right fungal starter culture. Information © The Authors 2025