Explanation:

- Alitame: This is indeed an aspartic acid-containing dipeptide sweetener discovered in the early 1980s. It is known to be about 2000 times sweeter than sucrose.

- Saccharin: This sweetener is older and not related to aspartic acid. It is less potent than Alitame.

- Aspartame: This sweetener contains aspartic acid but was discovered earlier, in 1965. It's about 200 times sweeter than sucrose.

- Sucralose: This is a chlorinated sugar compound, not containing aspartic acid, discovered in 1976.

Correct Answer: Alitame