Acesulfame potassium, 200 times sweeter than sugar, is an artificial sweetener used in food and beverage to replace sugar by providing a sweet taste with no calories and zero glycemic index, which may be helpful in controlling weight & obesity and benefit to diabetes. The European food additive number is E950. You might also see this ingredient listed as Ace-K or Acesulfame K in the food label.

http://www.chinafooding.com/Acesulfame-K