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. Upon addition to water, GDL is partially hydrolysed to gluconic acid, with the balance between the lactone form and the acid form established as a chemical equilibrium. The rate of hydrolysis of GDL is increased by heat and high pH. It is also a complete inhibitor of the enzyme amygdalin beta-glucosidase at concentrations of 1 mM.