Artificial sweetener which is stable only under cold conditions only is

aspartame

The artificial sweetener which is stable only under cold conditions only is 3. aspartame.

Aspartame is a methyl ester of a dipeptide formed from aspartic acid and phenylalanine. It is 200 times sweeter than sugar and is used in a variety of foods and beverages. Aspartame is not stable at high temperatures and can break down into harmful substances when heated. Therefore, it is only used in cold foods and beverages.

Saccharine, sucralose, and alitame are all stable at high temperatures and can be used in both hot and cold foods and beverages.