Glucono delta-lactone?(GDL) is a kind of excellent multifunctional food additive. It is mainly used as protein coagulant, acidifier, pickling, or?leavening agent. expander, preservative, seasonings, sequestrant, chelating agent, color-preserver, etc. it is widely applied to food, daily chemical industry, pharmaceuticals, cosmetics. Plastic and resinous modification, electrode position and polish, metal-surface cleaning and organic synthesis.