Glucono delta-lactone (GDL or lactone for short) is a multifunctional food additive, which is formed by oxidation of glucose into gluconic acid or its salt, purification, desalination, decoloration, concentration and crystallization. Internal grease is a nontoxic white crystalline or crystalline powder with almost no smell. Sweet first and then sour, easily soluble in water, slowly decomposed at 25℃.

What is said here is that the decomposition at 25℃ is slow, and the heating temperature must be higher than 25℃ before lactone can be decomposed into acetic acid!