After nearly two decades of research, scientists have finally broken the slush barrier.
They have figured out how to make a Slurpee out of diet soda.
Slushy soft drinks have been around for decades and come in a variety of flavors, from raspberry to pina colada. But even an 8-ounce serving can pack 65 to 240 calories, depending on the flavor - perfect for sugar-guzzling teens but bad for diet-conscious consumers and diabetics.
Until now, 7-Eleven Inc., parent of the Slurpee brand, and The ICEE Co., which has been making frozen, carbonated drinks since 1961, had little luck developing a zero-calorie, sugar-free version of their slushy sodas.
The reason: Sugar substitutes, such as NutraSweet, didn't behave like the real thing when subjected to freezing temperatures.
Desperate for a breakthrough, 7-Eleven challenged researchers at the nation's two leading soda brands - PepsiCo Inc. and Coca-Cola Inc. - to develop a workable recipe. Cola, after all, is the top-selling soft-drink flavor, regardless of brand.
The challenge paid off: Diet Pepsi Slurpees debuted Friday at 7-Eleven stores nationwide.
"We finally cracked the code," said Dave DeCecco, a spokesman for Pepsi-Cola North America. "High fives to everyone on our research-and-development team. ... Consumers have been asking for a diet-cola Slurpee for years. We wanted to be the ones to give it to them first."
Because a slushy soft drink had always required sugar to give it a smooth, semi-frozen consistency that can be "slurped" through a straw, developing a sugar-free product seemed impossible at first, 7-Eleven officials said.
Every sugar-substitute formula tried by researchers tended to turn the drink into a block of ice, said John Ryckevic, the Slurpee and Big Gulp category manager for the Dallas-based convenience-store chain.
Then there was the problem of temperature: Regular Slurpees freeze at 24 to 28 degrees Fahrenheit, while non-sugar prototypes seem to need temperatures a few degrees higher.
"There's a little bit of rocket science to it," Ryckevic said
Pepsi researchers finally settled on a winning formula consisting of three sweeteners - sucralose, erythritol and tagatose - that allows the diet cola to freeze with the right consistency without compromising its taste.
Even then, thousands of Slurpee machines needed adjusting so they would dispense the new diet beverage at the correct temperature. That's one reason the new flavor is debuting now, at the end of the summer, rather than earlier in the year, when the formula was successfully tested.
"This is something we've always wanted to have available to customers," Ryckevic said. "It's just taken a while to figure out the right blend of sweeteners."
The nation's largest convenience-store chain has been working on diet versions of its trademark Slurpee since the mid-1980s.
A decade ago, 7-Eleven tried a "light" version of its cherry-flavored Slurpee, but customers didn't like the taste, and the product was pulled. Two years ago, a sugar-free Crystal Light Slurpee was introduced, but that still came with some calories.
The company says Diet Pepsi Slurpee has fared well in early customer surveys: 88 percent of those who have tried it say they would buy it again, while 80 percent declare the taste and sweetness to be "just right."
"We're confident it will be a hit," Ryckevic said. "But, of course, the customer is the final judge."
Customers could eventually have more than one diet slushy to choose from. The ICEE Co., operated by J & J Snack Foods Corp. of Pennsauken, N.J., is still working on one, though it doesn't have plans to introduce a sugar-free Icee anytime soon, said Susan Swisher Woods, the company's marketing vice president.
"Sugar ... acts as a 'freezing control.' Without the exact amount of sugar, an ICEE would freeze up too hard and would not dispense from the machine to your cup," according to the ICEE Co. Web site. "A lot of research is being conducted to make a sugar-free Icee."
A diet slushy couldn't come at a better time, according to nutritionists.
The food industry, from fast-food chains to supermarkets, is adding more diet products to menus in an effort to appeal to health- and weight-conscious Americans, who are gobbling up more salads and low-fat foods.
One of every four soft drinks consumed in the United States last year was diet, according to The NPD Group, a consumer-research firm.
"It's a huge trend right now," said Christine Palumbo, a registered dietitian and nutrition expert in Naperville, Ill. "Low-carb, sugar-free and other diet products are multiplying on store shelves like rabbits." Even so, Americans still have a fondness for sweets and other junk foods, she said.
"For 7-Eleven to have a diet version of one of its sweetest treats, this is great news," Palumbo said.
At first glance, she said, the sugar-substitute blend used in the Diet Pepsi Slurpee doesn't raise any red flags or health concerns. Sucralose is similar to a sugar-substitute called Splenda that is available in grocery stores. Erythritol is commonly present in sugar-free candy. And tagatose is a non-nutritive sweetener that was most likely used sparingly, she said.
Kimberly Warren, a 36-year-old Orlando resident and avid Diet Pepsi drinker, tried the new Slurpee flavor last week at an Orlando 7-Eleven.
"Not bad," she said, sipping from the Slurpee cup. "It's real sweet but pretty refreshing."
Warren said she used to buy Crystal Light Slurpees but was turned off by the calorie count.
"I always drink diet soda," she said. "It's about time they had a diet Slurpee."
©2003, The Orlando Sentinel (Fla.).
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