Acesulfame K is a calorie-free sugar substitute (artificial sweetener).
Strucural Formula:

Acesulfame K is 200 times sweeter than sucrose (common sugar), as sweet as aspartame, about two-thirds as sweet as saccharin, and one-third as sweet as sucralose. Unlike aspartame, acesulfame K is stable under heat, even under moderately acidic or basic conditions, allowing it to be used as a food additive in baking, or in products that require a long shelf life.
Application:
As a non-nutritive sweetener, it can be widely used in various kinds of foods such as solid drinks, pickles, candied fruits, chewing gums and table-top sweeteners.