Cocoa shells are a residual stream with considerable market opportunities. This side stream is rich in fiber, but contains other interesting components like lignin. Wageningen Food & Biobased Research, together with Cargill Cocoa & Chocolate, Interface (Carpet Tile) and Schut Papier, aims to generate as many valuable components as possible via a biorefinery concept through separation of the individual components from these cocoa shells. This is done in the public-private research project on Cocoashells Biorefinery, supported by the Dutch Ministry of Economic Affairs.
As a side stream of the cocoa industry, cocoa shells are used in gardens to cover borders but can also be used as biomass to use for burning. According to Richard Gosselink of Wageningen Food & Biobased Research, it should be possible to find higher-value applications. 'Cacao shells contain lignin and fiber and the industry is interested in these components. But we also explore the possibilities of extracting other components with market potential, like flavor components.’
Mild separation process
Gosselink and his colleagues work in this project on an mild separation process to separate the main components at relatively low temperatures and without the use of chemical agents. This is necessary to prevent the main components from losing their functionality. Then, together with the project partners, it will be explored how to process these components into viable products.
Sustainable alternative for bitumen
For example, Wageningen Food & Biobased Research works together with carpet tile manufacturer Interface to provide a sustainable alternative for the backing of carpet tiles. The fossil-based bitumen is still used for this. Gosselink: 'Wageningen Food & Biobased Research has built up enhanced knowledge about lignin. When looking at the properties, lignin can perfectly compete with bitumen. For this specific application, we explore if we can replace the bitumen one-on-one with lignin from cocoa shells. A modification step may be needed to give the product the desired viscosity and adhesion.'
Sulfur-free pulp process
With Schut Papier, Wageningen Food & Biobased Research works on a sustainable biorefinery process to separate and process the fibers from the cocoa shells into specialty papers. ‘Together with the paper and pulp industry, we have considerable knowledge about fibers: how are they precisely assembled, how can a good distribution of fiber in finished products be assured and how can you make good paper products? In this project we choose a pulping process without the use of sulfur. We have successfully tested this process on lab scale and now want to take the next step with Schut Papier. This is an interesting development for the paper industry: the market opportunities for sustainably produced paper products are very favorable. '
Together with Cargill Cocoa & Chocolate, the supplier of cocoa shells, Wageningen Food & Biobased Research investigates what other valuable components from the residual cocoa shells could be gained. Gosselink: 'We have not identified all components yet, but Cargill is interested in flavor and other components to potentially apply in food and non-food applications. "
Follow-up with interested market parties
The project started in 2017 and is expected to conclude at the end of 2018. The first step is to define a viable separation process to get fibers and lignin which can be tested in application tests with the industry. According to Gosselink, it is likely that the cocoa shell contains more valuable components than the main streams than in this project addressed. ‘I can imagine exploring its possibilities in a follow-up project with interested market parties. The more value we can get from the cocoa shell, the greater potential for market success.’