Koji is a type of mold, specifically from the species Aspergillus oryzae, that is essential in the fermentation process of various Asian foods. It is commonly used to produce soy sauce, miso, and sake. The mold breaks down starches in grains, converting them into sugars, which are then fermented by yeast or bacteria. In addition to its culinary uses, koji is also valued for its health benefits. It contains enzymes that can aid digestion and enhance the nutritional profile of foods. As a result, koji has gained popularity in modern cooking and food production, especially among those interested in fermentation.