Glucono-delta-lactone
The short version
A mild slow-acting acidulant (GDL) — central to silken tofu coagulation and delayed-rise leavening.
It's widely considered safe at the amounts used in food, so we mark it green. The Safety section below has the details.
Where it comes from
The neutral cyclic form of gluconic acid, present naturally in honey, fruit juices, and wine. Produced industrially by fermentation of glucose with Aspergillus niger followed by lactonization. A historic Japanese tofu coagulant.
How it's used
The dominant coagulant for silken tofu — its slow hydrolysis to gluconic acid produces a delicate, even coagulation. Also used in slow-acting baking powders, cured meats, and dairy products where gradual acid release is preferred over fast acids.
Safety profile
No ADI specified. Considered safe and a natural metabolic intermediate. Slowly hydrolyzes in water and the digestive tract to gluconic acid, which is metabolized normally.
Physical & chemical properties
White crystalline powder, freely soluble in water. In solution, slowly hydrolyzes (over minutes to hours) to gluconic acid, releasing protons gradually — the basis for slow leavening and gentle coagulation.
Regulation worldwide
Permitted globally without restrictive limits for food use.
Educational information only. Not medical or dietary advice.