Does Diet Pepsi really taste any different?

It's out with the old and in with the new at Diet Pepsi. As of this week, Diet Pepsi fans may notice something different in the soft drink aisle.

That's because the brand is shifting away from artificial sweetener aspartame, an ingredient that's drawn public concern, in favor of sucralose and acesulfame potassium.

The move comes as Pepsi tries to reserve a slide in sales of the diet drink. Diet Pepsi volume dropped 5.2 percent last year, according to industry tracker Beverage-Digest.