In 2010, 4.2 billion gallons of diet soft drinks were sold in the U.S., according to Beverage Marketing Corp. But diet colas weren’t always a hit.
In the 1950s, 60s and 70s, consumers weren’t necessarily keen on the bitter aftertaste associated with diet sodas due to artificial sweeteners like cyclamate and saccharin.
The diet soft drink market really started to pick up steam in the 1980s, not coincidentally in time with the FDA’s approval of the sweetener aspartame, which was used in Diet Coke when it debuted in 1982 and in a reformulated version of Diet Pepsi replacing saccharin as its sweetener.
Product developers at the major soft drink companies are faced with the challenge of creating a carbonated soft drink that tastes just like a sugar-sweetened beverage, but with artificial or natural non-nutritive sweeteners that don’t have the sweetness, flavor or mouthfeel of sugar. The introduction of aspartame was a turning point, as the sweetener has a taste profile very close to that of sugar. And according to formulators, it’s a challenge that continues.
“We need to know what tools we have available to us,” says Kate Ratliff, technical director at Flavorman, a product development company based in Louisville, Ky. Flavorman has worked with small and large beverage companies to develop new beverages or reformulate existing ones.
Cost is always an issue. A premium diet soft drink marketed on a smaller scale can use an ingredient like Reb-A , a stevia sweetener, which is more expensive, whereas the big manufacturers are selling their products on a much larger scale and costlier ingredients might not fit into their pricing structure, Ratliff notes.
Packaging and shelf life also are big factors to consider prior to formulation, as that can determine the sweeteners used.
“The perceived sweetness of aspartame starts to diminish after three or four months, so with a product that has a quick turnaround on the shelf, you might use aspartame,” Ratliff says. “If it’s a new-to-market product, you might use a sweetener blend, such as sucralose and acesulfame potassium, as they have a much longer shelf life.”
Taking sugar out of the equation doesn’t just alter the soda’s taste, but it also changes the balance between acid and sweetness, the flavor delivery and release and the mouthfeel, often called “body,” that consumers experience when drinking a full-calorie soda.
“There are a number of consumers who say that when they drink diet it has a little bit of a thin taste, it doesn’t have the full mouthfeel, full flavor they get from regular soft drinks,” says Andrew Springate, senior vice president, brand marketing at Dr Pepper Snapple Group. The company used these insights to develop its latest reduced-calorie product, Dr Pepper Ten, which has 10 calories and 2 grams of sugar. The product, which launched nationally last October, contains a mixture of high fructose corn syrup and zero-calorie artificial sweeteners.
Cargill developed a novel technology to help formulators overcome the challenge of balancing mouthfeel and taste when making diet drinks. Cargill’s TasteWise solution uses the science of friction, called tribology, to measure and mimic what goes on inside the mouth when a drink is consumed, according to Andy Del-Rosal, team leader of beverage application scientists at Cargill.
“We call it the taste triangle. You have to balance flavor, sweetness and mouthfeel. If you tweak one, it tweaks the others,” he says. “Adding texture back in will, in turn, impact the flavor and sweetness profile.”
The real test though is when a new diet CSD hits the market. It can either take off like Coke Zero and, so far,
Dr Pepper Ten, or fizzle like Pepsi Edge and C2, in which case, it’s back to the lab.