Glucono delta-lactone (GDL, E575) is a food additive commonly used as an acidulant and pH regulator in various food products, including dairy, baked goods, and tofu. It is produced through the fermentation of glucose, commonly derived from cornstarch, by Aspergillus niger to produce gluconic acid, of which GDL is an ester. GDL lowers the pH of food products and can act as a leavening agent in some baking applications. It is also used as a curing and pickling agent, as well as a color enhancer in meat products. It naturally occurs in certain foods, such as honey, wine, and other fermented foods.