Scientists at the Technical University of Munich (TUM) and the Leibniz Institute of Food Systems Biology (LSB) have developed a new methodology that quickly, easily and precisely quantifies the flavor profile of cocoa samples.

A plethora of flavor compounds contribute to the distinctive taste of cocoa, and its composition can be challenging to analyze. 

The new method is already suitable for practical use in companies and can be applied at any point along the value chain, from cocoa beans to chocolate. 

In addition, the initial research results obtained using this method “lay the foundation for a world map containing comprehensive data on flavor-relevant cocoa ingredients,” say the scientists. 

“In the future, such a map could help to further optimize processing and production processes by making the flavor profiles of cocoa-containing products, such as chocolate, objectively predictable based on molecular parameters,” explains food chemist Andreas Dunkel of the LSB, who played a leading role in the study.

A plethora of flavor compounds contribute to the distinctive taste of cocoa, and its composition can be challenging to analyze.Flavors are decisive
Various flavor substances, including secondary plant compounds, such as health-promoting flavanols, are crucial for the taste of cocoa. 

The particular class of these substances creates the typical astringent feeling in the mouth, which comes across as the pleasantly bitter and slightly sour taste of cocoa or chocolate.

In cocoa-producing countries, cocoa quality assessment is carried out mainly by random visual inspection of the beans (cut test) and sensory trained personnel. In addition, chocolate manufacturers use time-consuming and personnel-intensive methods to test the quality of cocoa. 

The new method offers “significant advantages” over these conventional analytical methods. 

“Our new methodology requires minimal sample preparation and provides quantitative data on 66 taste-decisive substances using a single mass spectrometric platform,” adds Thomas Kauz, who made contributions to the development of the method as part of his doctoral thesis at the Chair of Food Chemistry and Molecular Sensory Analysis at TUM. 

“Traditional techniques make it possible to analyze about ten samples per week, wheras this new method allows an analysis of 200 in that time,” according to Professor Corinna Dawid, who is head of the department on behalf of Professor Thomas Hofmann. 

Furthermore, she says the methodology can be easily implemented into industrial workflows.

To understand the influence of plant genetics, breeding and processing on the sensory profile of cocoa products, high-throughput sensometabolite quantitation must be performed throughout all of these steps. 

In this work, the scientists present a rapid, sensitive, and robust quantitation method on a single ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) platform, requiring minimal workup for any sample type from farm to fork.

Samples from around the world
The team of scientists tested their new methodology on a set of 75 cocoa samples worldwide. They compared unroasted samples with those the researchers had roasted in the lab using a uniform standard procedure. 

“Interestingly, we found that the roasting of the cocoa influenced the flavor profile more than the respective regional origin of the beans,” Dunkel notes.

With the help of the new methodology, it is now possible to investigate the influence of other factors, including the genetic predisposition of the plants and the type of fermentation. 

Meanwhile, Professor Veronika Somoza, director of the LSB, and Dawid both agree that a long-term goal of the joint research at TUM and LSB is to supplement the world map of cocoa with all these data on active sensory substances.