News - May 28, 2020

Acetic acid in chocolate reveals origin  

Albert Sikkema

PhD student Valentina Acierno looked for specific traits in chocolate that can be traced back to the country of origin and the growing conditions of the cocoa beans used. Various substances in the chocolate pointed her in the right direction.

© Shutterstock

Acierno graduated earlier this month with a PhD project supervised by Saskia van Ruth, professor of Food Authenticity and Integrity at Wageningen. She researched how you can trace which species of cocoa bean – Criollo, Forastero or Trinitario – the chocolate was made from, and on which continent – Africa, South-East Asia or Latin America – the beans were grown. In other words: she researched the botanical and geographical origin of the chocolate using volatile and non-volatile compounds and isotopes from the different cocoa beans. To do this, she looked for ‘markers’ that can be measured during the stages of production, processing and consumption.

When Acierno compared the composition of the various cocoa beans from different countries, it turned out that acetic acid concentrations were characteristic for the Criollo cocoa bean throughout the entire production chain. What is more, the level of acetic acid provided information about the fermentation and drying conditions of the three different cocoa beans. She found other markers too, but they only gave information at specific points along the production chain, making them suitable as quality control instruments for use on either the beans or the chocolate, but not on both.

Acierno’s results have not been applied yet by quality control organizations such as the Netherlands Food and Consumer Product Safety Organization. She thinks researchers will first need to analyse many more samples to confirm her markers. It is also important to compare cocoa from several different years, to clarify the effect of things like weather conditions on the profile of the cocoa beans. And more knowledge of the local conditions for the drying and fermentation of the cocoa beans could make it possible to locate the chocolate’s origin more precisely, says Acierno.

Her research is important for Dutch chocolate producers and labels such as Max Havelaar. Under Dutch legislation, all chocolate produced in the Netherlands must fulfil sustainability criteria by 2025. So both the buyers and the consumers need to know where the cocoa beans come from and whether the cocoa farmers and processors keep to sustainable practices and Fair Trade agreements.