Aberrations in the fermentation and drying of raw cocoa can lead to the generation of dangerous mould toxins. An interdisciplinary project is aimed at demonstrating how to minimize these toxins and increase product safety.
By Dr. Jörg Häseler
High sensory quality raw cocoas are essential for high-quality dark chocolate. This quality depends heavily on the genetic background of the cocoa trees, and on the fermentation and drying processes. During drying, the preliminary phases of the chocolate flavour development begin in the cocoa seeds while bitter constituents are broken down. Incorrect fermentation, however, can produce undesired flavours and mycotoxin (fungus toxin) contaminations, in particular with Ochratoxin A (OTA), a substance capable of causing kidney diseases and, in some cases, cancer.
OTA is formed, among others, by lower fungi. When storage conditions are not ideal, the corresponding toxin catalysts can even develop in mild climatic zones. OTA is found almost exclusively in plant-based food products around the world such as grains, coffee, grapes and products made from them, as well as in cocoa, nuts and spices. The big problem with OTA is that once contaminated products have been consumed by humans, they are only expelled from the body at a very slow pace.
The possible contamination of raw cocoa apparently results predominantly from aberrations occurring during fermentation and drying which allow the dangerous moulds to establish themselves. The influence and, above all, the interplay between these factors in the development of specific biochemical and sensory profiles have not been conclusively investigated. Nevertheless, the worldwide standard is still a spontaneous fermentation process which as such does not really accommodate any genuine process supervision. This is one of the reasons why raw cocoa is characterised by a high, unsatisfactory level of qualitative heterogeneity.
On the road to “Flavour on demand”
This is further complicated by the fact that as a result of increasing consumption, the quantities of raw cocoa produced frequently are inadequate for covering the industry’s needs. Because of this, chocolate manufacturers are experiencing increasing difficulties with the acquisition of raw cocoa of a consistent sensory quality. At the same time, raw cocoas with specific sensory properties and a definitively identified origin are becoming ever more important.
Now, factors like how the cocoa genotype, the cultivation conditions, the fermentation with selected starter cultures and the drying process influence the development of specific sensory profiles are set to be systematically investigated. Five research groups from Germany and Peru will work together to unlock the secrets of the sensory development of raw cocoa. The interdisciplinary project “Quality-improved cocoa and cocoa-based products with flavour profiles on-demand – From the farmer to the chocolate bar” will set up a model processing chain comprising every step of processing.
This includes the influence and interplay between cultivation conditions, the cocoa genotype, cocoa seed physiology, the fruit pulp, fermentation with selected starter cultures and drying in the development of specific biochemical compounds and sensory properties in raw cocoa and chocolate. Testing of the suitability of rapid analysis and control methods for the specific quality characteristics will also be conducted at the same time.
