Enzyme-assisted hydrolysis of Theobroma cacao L. pulp

Cocoa pulp, a by-product of the cocoa supply chain, has gained the food sector's attention for its pleasant flavour. Enzyme-assisted technologies to facilitate its separation from the cocoa seeds remain largely unexplored. We studied the effects of temperature, enzyme activity and enzyme combinations on the physicochemical properties of cocoa pulp by Response Surface Methodology and D-optimal design. Endo-polygalacturonase, endo-cellulase and hemicellulase activities were investigated. A reduced quadratic model described the relative reduction in viscosity, of the particle diameter d_v,0.9 and of the browning index. Polygalacturonase had the strongest influence on viscosity, while cellulase had the least effect. Synergistic effects of polygalacturonase with cellulase and/or hemicellulase were identified. The model predicted maximal reductions in viscosity by 70.3 % with 275 U of polygalacturonase and 275 U of hemicellulase at 40 °C. Fresh pulp's d_v,0.9 was 613 μm. Combining all enzyme activities reduced the d_v,0.9–418 μm (40 °C, total activity: 580 U). Only the temperature proved to significantly influence the browning index, with higher temperatures causing a higher colouring effect. Lastly, the model was successfully validated for the relative reduction in viscosity and the d_v,0.9. Our study provides key insights into the enzyme-assisted processing of cocoa pulp, facilitating its separation from the seeds. By utilising the pulp, innovative ingredients can be developed for the food sector, and at the same time, the added value in the cocoa supply chain can be improved.