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Cocoa post-harvest processing

Key topic in the Research group of Food Biotechnology

The first step in the production of the raw material for Switzerland's flagship product, chocolate, is the post-harvest process in the countries of origin. This consists of spontaneous fermentation of the cocoa beans followed by drying. Fermentation is a complex, spontaneous process that initiates the formation of flavor precursors in the bean, among other components.

We consider the entire post-harvest process of cacao in its influence on the quality of the fermented, dried beans and ultimately the chocolate. We follow microbial biodiversity and its influence on the post-harvest process, but also chemical, physical, and sensory parameters with the aim of identifying correlations and applying them in optimization strategies. Such optimizations range from simple adjustments in the execution of the traditional post-harvest process to the application of functional cultures that form bioactive metabolites. One focus is on aroma-active cultures and antifungal protective cultures with their target organisms i.e., mycotoxin-producing molds.

Recently, the use of the surplus pulp, the so-called cocoa pulp, has become an increasingly prominent issue. In this context, we are working on the one hand on the bio-valorisation of the part of the cocoa pulp that is not needed in the spontaneous fermentation during the post-harvest processing of the cocoa beans and on the other hand on the fermentation and drying process of the partially de-pulped beans in order to ultimately use the whole cocoa fruit for the production of food.

In our projects, we work closely with producers and research institutes in the countries of origin, especially Honduras, Ecuador, Bolivia and Ghana. A transfer of know-how is central here and is also of particular importance from an intercultural point of view. In addition, we work closely together with the Food Chemistry Research Group and the Sensory Research Group to identify important compounds and flavors in cocoa beans and to assess their influence on taste.

In 2022, together with other research groups at the HAW Departement of Life Sciences and Facility Management, we were able to establish the Center of Cocoa and Chocolate Competences,enabling us to present research along the cocoa value chain under one roof.

Research Projects