Two compounds related to the bitterness of coffee

Add some milk and sugar to a steaming cup of coffee, which is a sign for many people to start a new day. Although this is done to coordinate the bitterness of the drink, the reason why coffee makes us frown has been wondered by scientists for decades. Now, researchers have narrowed down the typical scope of this exploration by identifying two compounds associated with the bitterness of coffee, whether gentle breakfast coffee or Italian espresso. A study presented at the annual meeting of the American Chemical Society in Boston showed that it was the roasting process-not the coffee beans themselves-that produced these compounds, a discovery that opened the door to improving the processing of coffee beans.

A cup of coffee is a complex drink made up of more than 30 chemicals that determine the taste, aroma and acidity of the coffee. Since the 1930s, scientists have broken up and identified a variety of chemicals related to the sensory composition of coffee, but no one can figure out what makes coffee so bitter.

To understand the mystery, ThomasHofmann, a food chemist at the University of Technology in Munich, Germany, and his colleagues continuously filtered the brewed coffee. They found that a small portion of the filter products contained the smallest and most bitter compounds, which was no doubt provided by the scandium team's in-depth analysis. Using mass spectrometry analysis, the researchers determined that one of its compounds is the differentiation product of chlorogenic acid lactone-chlorogenic acid, which exists in almost all plants. The team then baked a range of drinks from popular coffee to bitter coffee and measured the number of chlorogenic lactone in each coffee.

The researchers found that roasted coffee beans produce a continuous spinning hook. first, the chlorogenic acid in the coffee beans is converted into chlorogenic acid lactone, and then, if the processing continues, the latter will differentiate into phenyl dihydroindene. Hofmann pointed out that chlorogenic acid lactone can produce moderate bitterness in lightly or moderately roasted coffee, while subsequent secondary differentiation products are the root cause of the "bitterness" of espresso.

PeterMartin, a professor of neurology at Vanderbilt University in Nashville, Tennessee, suggests that the identification of secondary differentiation products provides new material for studying the potential health effects of coffee. Martin is currently the director of the University's Coffee Research Institute. "just as we know very little about chlorogenic acid, we don't know much about other products related to it," he said. " "this study broadens our horizons and gives us a better understanding of the effects of coffee on health," Martin said. "for coffee wealth, it will help improve the taste of coffee."