Cocoa bean skin waste as potential raw material for liquid smoke production

Cocoa bean skin is a waste of chocolate industries that mostly contains hemicellulose, cellulose, and lignin. This material shows to be a promising feedstock for the production of liquid smoke and charcoal. The study was aimed to analyse the influence of temperature and heating rate of cocoa bean skin pyrolysis to the production of liquid smoke. Optimization of pyrolysis process variables, i.e. by adjusting the suitable temperature and heating rate, is the key to obtain a high-quality product. The pyrolysis process was carried out using heating rates between 5°C/min and 15°C/min at three pyrolysis temperatures of 450°C, 500°C, and 550°C. The yield of the produced liquid smoke was in the range of 18-23%. It showed that at a faster heating rate, the reaction produced more charcoal, ash, and water content for all pyrolysis temperatures. The highest yield of charcoal was ca. 39% with a caloric value of 22.97 MJ/kg, while the lowest ash and water content was in the range of 16.5-19% and 6.5-8.5%, respectively. This result shows that the utilization of this organic waste compounds could be promising for large-scale production.