In mid-June, more than 100 participants attended the 8th Cocoa Round Table conference in Hamburg. Under the motto “A Quality Vision for the Future”, attendees gathered eager for an exchange of scientific knowledge. One of the many interesting things revealed at the ­conference, sponsored by Germany’s chocolate trade association “Stiftung der Deutschen Kakao- und Schokoladenwirtschaft”, was how climate change could affect cocoa farming.

By Dr. Jörg Häseler

The Cocoa Round Table 2019 kicked off with a presentation by Dr Lyndel W. Meinhardt (Agricultural Research Service, USDA) featuring a special focus on cocoa bean quality. Dr Meinhardt spoke in this regard about the current state of knowledge on genetic diversity in cocoa, asserting that this information is very useful when purchasing the raw materials since it can be used to determine with great precision where the cocoa beans originated. He also reported that 30 to 40 % of containers are incorrectly labelled with the wrong bean varieties. Dr Meinhardt additionally presented results from his study on the individual base pairs in a complementary DNA double strand.

This point was also picked up by Andreas Dunkel from the work group headed by Prof. Dr Thomas Hofmann (TU Munich, Professor for Food Chemistry and Molecular Sensory Science). However, the basis for Mr Dunkel’s observations was taken from the unique ingredients profiles of cocoa beans from producer countries all over the world, with special attention given to sensorily active ingredients. He made an impressive statement asserting that a chocolate recombinant can be created with contents including theobromine, epicatechin, four amino acid derivates, ten diketopiperazines and four organic acids. Mr Dunkel explained: “In the course of the metabolome research we conducted, we were able to clearly identify in excess of 2,500 substances, some 1,700 of which we added to a spectra library”.

Afterwards, Prof. Dr Matthias S.
Ullrich (Jacobs University Bremen, Dept. Life Sciences and Chemistry) discussed his protein and peptide
analytics results, with a focus on the storage protein phaseolin, one of more than 800 proteins present in cocoa. The level of phaseolin is reduced during fermentation, and Dr Ullrich precisely documented this process whereby the resulting peptides form flavour precursors. Ultimately, the amino acid sequence PVNSPGKY produces a nutty flavour, while a pleasant, sweet flavour emerges from NNPYY.

Strategies for minimizing cadmium contamination played a large role during the event, with new approaches presented for avoiding this situation. This is absolutely necessary, particularly since children represent a consumer group near the established thresholds. Dr Mirjam Pulleman (CIAT) explained the corresponding approaches in Ecuador, Peru and Columbia, the countries primarily affected by the thresholds. She cited figures of 50 % affected batches. Biotic and abiotic factors play a role here and are specifically related to the soil. It therefore seems logical to first inspect the soil. Cadmium content minimization should also be considered in observing genotypes and seasons.

Tony Lass (Chairman of the Cocoa Research Association Ltd.) closed out the first day of the conference with a passionate plea for genetic diversity and the benefits offered by the two corresponding collections in Costa Rica and Trinidad. He issued a call to support initiatives aimed at maintaining this diversity and using it as needed.

The second day started off with PD Dr Martin Steinhaus (Leibniz-Institute for Food Systems Biology) speaking about cocoa off-flavours. Among other things, he and his team have managed to identify the specific connections responsible for both a smoky, ham-like flavour and a mouldy flavour. However, the process steps that form these substances and how they can be avoided remain unresolved for now.

Post-harvest treatment was an-other main topic. Dr Susanne Miescher Schwenninger (Zurich University of Applied Sciences) demonstrated how the deployment of starter cultures (Lactobacillus fermentum and Saccharomyces cerevisiae) can be used to reduce malfermentation and mould infestation. She also noted that a new type of fermentation process used in Brazil enables better process control. Norberto Hess presented the equipment for fermentation and drying that can be controlled online, citing the benefits he elaborated: “Equipment is used for this that can also be built in smaller dimensions with simple utensils”.

Dr Christian Andres (Research Institute of Organic Agriculture, Cocoa/Agroforestry and ETH Zurich) pre-sented cocoa plantation design possi-bilities. He also cited the negative effects of climate change on plantations in Bolivia and Ghana, and how these effects can be buffered.

Dr Christian Bunn (International Cen-ter for Tropical Agriculture) reported on the climatic changes that can be anticipated in the coming decades in the main farming areas, and illustrated how they could affect cocoa farming. He presented planting systems and management concepts for reducing the associated negative consequen-ces. Dr Bunn asserted that the cocoa farming industry should combat climate change with a three-phased strategy:
1. Determination of the climate zone under current and future conditions
2. Determination of the level and scope of the possible change
3. Observation of trends that have
already appeared.

He also recommended addressing the topic in a manner directed at the specific target group in order to persuade cocoa farmers that they need to act. According to his statements, parts of the situation are not entirely clear; for instance, there can be no firm conclusions drawn yet regarding which pests will be displaced by climate change, or whether in fact their growth might even benefit from it.

The Poster Flash Talks, promoting the scientific work of the next generations of scientists, proved to be an enormous enrichment to the event programme. And the internationalization of the conference with guests and speakers from places including Brazil, Switzerland, Belgium and the Netherlands had a very positive effect on the quality of the conference. As a result, everyone should already mark their calendars for June of 2021 and the upcoming 9th Cocoa Round Table conference.