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2007-8-28 16:11:27 |
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Dark roasted coffee tastes bitter only partially due to the presence of caffeine. A new study found other compounds in roast coffee actually play a bigger role in the bitterness. Thomas Hofmann, a food chemistry professor from the Technical University of Munich in Germany and colleagues found that caffeine is only responsible for 15 percent of coffee's bitter taste. Hofmann and colleagues found two classes of compounds that render coffee's bitterness. And both are antioxidants that are only formed during the roasting of coffee beans, not in raw coffee beans. The findings were presented today at a meeting of the American Chemical Society in Boston. One class known as chlorogenic acid lactones is present at high levels in light to medium roast coffees. Highly roasted coffees such as espresso have harshness note, which is caused by compounds known as phenylindanes, a degradation product from chlorogenic acid lactones. "Roasting is the key factor driving bitter taste in coffee beans. So the stronger you roast the coffee, the more harsh it tends to get," Hofmann was quoted as saying. In addition to the formation of harsh compounds, prolonged roasting leads to the formation of the bitterest compounds as well. So dark roasted coffees tend to be very bitter and harsh. |
