Stop the presses – sugar doesn't melt, it decomposes. This news would make Willy Wonka giddy with delight. Not only is this a revolutionary discovery, it also means caramels will be tastier and pharmaceutical companies can tout with confidence that a spoonful of sugar will help the medicine go down.
Researchers at the University of Illinois made this discovery and according to Shelly J. Schmidt, a professor of food chemistry, this is a good thing when it comes to flavor and texture.
In a presentation to the Institute of Food Technologists about the importance of the new discovery, Schmidt told the food scientists they could use the new findings to manipulate sugars and improve their products' flavor and consistency.
According to a press release found on the University's website, "Certain flavor compounds give you a nice caramel flavor, whereas others give you a burnt or bitter taste. Food scientists will now be able to make more of the desirable flavors because they won't have to heat to a 'melting' temperature but can instead hold sugar over a low temperature for a longer period of time," notes Schmidt.
Schmidt and graduate student Joo Won Lee didn't intend to turn an established rule of food science on its head. But they began to suspect that something was amiss when they couldn't get a constant melting point for sucrose in the work that they were doing.
"In the literature, the melting point for sucrose varies widely, but scientists have always blamed these differences on impurities and instrumentation differences. However, there are certain things you'd expect to see if those factors were causing the variations, and we weren't seeing them," says Schmidt.
The scientists determined that the melting point of sugar was heating-rate dependent.
"We saw different results depending on how quickly we heated the sucrose. That led us to believe that molecules were beginning to break down as part of a kinetic process," according to Schmidt.
Schmidt said a true or thermodynamic melting material, which melts at a consistent, repeatable temperature, retains its chemical identity when transitioning from the solid to the liquid state. She and Lee used high-performance liquid chromatography to see if sucrose was sucrose both before and after "melting." It wasn't.
"As soon as we detected melting, decomposition components of sucrose started showing up," she said.
To distinguish "melting" caused by decomposition from thermodynamic melting, the researchers have coined a new name--"apparent melting." Schmidt and her colleagues have shown that glucose and fructose are also apparent melting materials.
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