Imagine the crisp, refreshing sensation of peppermint chewing gum. Now, imagine it without the mint.
That's a possibility proposed by researchers who've created a compound that delivers a more potent version of the cooling sensation of menthol, without the minty taste or smell.
Thomas Hofmann and his colleagues at the German Research Center for Food Chemistry in Garching, Germany, recently identified four natural cooling compounds in malt. The team has now synthesized 26 compounds similar to the natural ones and tested the new compounds on trained tasters.
The researchers found that substituting an oxygen atom for a carbon in one of the natural structure's rings increased the compound's cooling power. Other alterations, such as adding carbon and hydrogen atoms, decreased the cooling sensation.
The best of the newly designed compounds has 35 times the mouth-cooling power of menthol. When applied to the skin, it's 250 times cooler than menthol, says Hofmann, who with his colleagues reports the results in the Nov. 19 Journal of Agricultural and Food Chemistry. The compound's cool sensation also lasts twice as long as menthol's does, the researchers report.
"The higher cooling activity opens the possibility to use the materials in lower concentrations to impart the same cooling effect as known from menthol," says Hofmann. Moreover, menthol's minty smell isn't desirable in all products, he says.
Hofmann envisions that in 2 years, chocolates, citrus drinks, water, shower gels, toothpaste, or other products could use one of the new chemicals to provide a nonminty cool.
Ottinger, H., Y. Soldo, and T. Hofmann. 2001. Systematic studies on structure and physiological activity of cyclic α-keto enamines, a novel class of "cooling" compounds. Journal of Agricultural and Food Chemistry 49(Nov. 19):5383–5390.
2001. Cool chemistry: Researchers create potent new cooling agent, odorless and tasteless. American Chemical Society press release. Nov. 6. Available at ScienceDaily.com.
Deutsche Forschungsanstalt für Lebensmittelchemie
From Science News, Volume 160, No. 24, December 15, 2001, p. 383.