Raw cocoa beans have an intense, bitter taste and must be processed to bring out their characteristic flavour but there is still a lack in knowledge on the key compounds responsible for the odour and taste profile of roasted cocoa, and, in particular, on their precursors and formation pathways.
“To make a very good cocoa aroma, you need only 25 of the nearly 600 volatile compounds present in the beans," said Schieberle, a professor at the Institute for Food Chemistry at the Technical University of Munich.
He described the outcome on his team’s research into cocoa aromas at this week’s 242nd National Meeting & Exposition of the American Chemical Society (ACS) at which he also received the 2011 ACS Award for the Advancement of Application of Agricultural and Food Chemistry.
The German team’s research can be filed under the terms sensomics, whichinvolves compiling a profile of the key chemical players responsible for giving specific foods their distinctive taste and aroma.
The sensory specialists report they first characterized and quantified aroma and taste compounds of roasted cocoa and then monitored selected flavour molecules during fermentation and roasting.
The team explained that, using systematic model experiments, they were able to reveal new routes of the Strecker reaction, which show that different precursors are active in generating the malty and honey-like aromas of Strecker aldehydes during fermentation compared to reactions during roasting and, finally, during mastication in the human mouth.
The German researchers also report they have uncovered a way to improve the taste of chocolate.
Much of the chocolate used in baking, ice cream and hot cocoa undergoes "Dutch processing," which gives it a milder taste. The researchers found that the addition of sugar to the cocoa before this standard processing method will result in a more velvety chocolate.
The flavours of chocolate and other foods come not just from taste buds in the mouth, Schieberle noted. Odor receptors in the nose play an important role in the perception of aroma. The professor and his colleagues identified various substances present in cocoa for aromas that bind to human odor receptors in the nose.
They said they mimicked the overall chocolate flavor in so-called ‘recombinates’ containing those ingredients, and taste testers could not tell the difference when they sampled some of those formulations.
Raphael Wermuth, a spokesperson for pod to pallet cocoa supplier, reacted positively to the developments from Schierberle’s team.
He told ConfectioneryNews.com that the final aroma of chocolate depends on the bean origin, the fermentation and drying process as well as on the roasting of the beans and conching of the chocolate. “Focusing on these three steps is how we, Barry Callebaut, determine each chocolate’s characteristic taste and smell,” he added.