Glucono delta-lactone (GDL), also known as gluconolactone, is a food additive with the E number E575 used as a sequestrant, an acidifier, or a curing, pickling, or leavening agent. It is a lactone of D-gluconic acid. Pure GDL is a white odorless crystalline powder.
GDL has been marketed for use in feta cheese. GDL is neutral but hydrolyzes in water to gluconic acid which is acidic, adding a tangy taste to foods, though it has roughly a third of the sourness of citric acid. It is metabolized to 6-phospho-D-gluconate; one gram of GDL yields roughly the same amount of metabolic energy as one gram of sugar.
