BMWK - IGF - AIF- FEI - Fehlaromastoffe in Rohkakao

The key raw material for the production of chocolate and cocoa drinks is the seed of the cocoa tree Theobroma cacao L. Around 38% of the raw cocoa produced worldwide, around 1.6 million tons, is ground in Europe, around 400,000 tons of which is produced in Germany. The majority of medium-sized companies (SMEs) in the German cocoa and chocolate goods industry traditionally purchase raw cocoa from international trading companies. However, there is a strong trend towards more involvement in the cocoa-growing countries in order to exert greater influence on the quality of the raw cocoa there. As a result, SMEs in particular are currently very successfully tapping into new market niches with high-quality chocolate products in the "single origin" and "single plantation" segments.
A major problem with raw cocoa is the sporadic occurrence of batches with off-flavors. Such batches of raw cocoa are detected at rather irregular intervals and with a typical frequency of several occurrences per company and year. Some clearly characterizable and easily distinguishable off-flavours occur again and again. Off-flavored batches of raw cocoa pose a considerable problem for the German cocoa and chocolate industry. If raw goods contaminated with off-flavors enter production, the off-flavor may still be perceptible in the finished products. Entire batches may then have to be destroyed - with economic damage that can be in the six-figure euro range even for smaller companies. If the products have already been placed on the market, there is also the threat of a considerable loss of image.
Until recently, there was little data available on the substances that trigger off-flavors and their critical concentrations in raw cocoa. This knowledge gap was closed as part of the FEI project AiF 19455 N. Based on this knowledge, the aim of the research project was to clarify which process parameters during processing and storage lead to the formation of these off-flavours in order to derive recommendations for action and minimize the risk of off-flavour formation in raw cocoa production in a timely manner.

Preliminary tests investigated the influence of over-fermentation and contact with wood smoke during cocoa drying on the occurrence of smoky off-flavors. In the main part of the project, on-site trials were conducted in the cocoa-growing countries of Nicaragua and Costa Rica, specifically varying parameters of fermentation, drying, and storage to investigate their influence on the formation of off-flavors.
It was found that the phenols responsible for the smoky off-flavor can be formed both through contact with wood smoke and through fermentation errors, in particular over-fermentation. The carboxylic acids responsible for cheesy off-flavors are formed, among other things, by insufficient mixing during fermentation, over-fermentation, and delayed drying due to, for example, insufficient turning of the material or excessive layer thickness. However, rapid oven drying is not an alternative, as this leaves too much acetic acid in the cocoa. Geosmin, which is responsible for earthy, moldy off-flavors, can form if mixing during fermentation is insufficient, but also after insufficient drying during subsequent storage.

BMWK - IGF - AiF - FEI

Industrielle Gemeinschaftsforschung (IGF)