Glucono delta-lactone (GDL) food grade comes in a white odorless crystalline powder form which is a naturally-occurring food additive used as a coagulant, sequestrant, an acidifier, or a curing, pickling, or leavening agent. It is a lactone (cyclic ester) of D-gluconic acid.

Glucono-1,5-Lactone or GdL is a neutral cyclic ester of gluconic acid, produced with the acid by fermentation of glucose. It is separated from the acid by crystallisation.

GDL is commonly found in honey, fruit juices, and wine. GDL is neutral, but hydrolyses 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 glucose; one gram of GDL yields roughly the same amount of metabolic energy as one gram of sugar.

As an acidifier, is used in cheese manufacturing.

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.
Source: wikipedia.org

Produces a very fine delicate pudding-like textured tofu that is almost jelly-like. This coagulant is used especially for “silken” and softer tofus, and confers an almost imperceptible sour taste to the finished product. Commonly used together with calcium sulfate and magnesium chloride to give soft tofu a smooth tender texture.

NOTE: This DOES NOT contain lactose, it is safe for the lactose intolerant.

Suggested Directions: To make tofu fah/silken (douhua/tau foo fa/tau huay), mix 1 teaspoon of GdL with 1 quart of warm soymilk. It will set in about 1 hour.

CAS No.: 90-80-2

Read More About It
Making Tofu at Home article from Wordpress.com