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Characterization and Degradation of Pectic Polysaccharides in Cocoa Pulp

Meersman, Esther, Struyf, Nore, Kyomugasho, Clare, Jamsazzadeh Kermani, Zahra, Santiago, Jihan Santanina, Baert, Eline, Hemdane, Sami, Vrancken, Gino, Verstrepen, Kevin J., Courtin, Christophe M., Hendrickx, Marc, Steensels, Jan
Journal of agricultural and food chemistry 2017 v.65 no.44 pp. 9726-9734
chocolate, cocoa beans, enzyme activity, factories, fermentation, genes, pectins, polygalacturonase, pulp, starter cultures, temperature, yeasts
Microbial fermentation of the viscous pulp surrounding cocoa beans is a crucial step in chocolate production. During this process, the pulp is degraded, after which the beans are dried and shipped to factories for further processing. Despite its central role in chocolate production, pulp degradation, which is assumed to be a result of pectin breakdown, has not been thoroughly investigated. Therefore, this study provides a comprehensive physicochemical analysis of cocoa pulp, focusing on pectic polysaccharides, and the factors influencing its degradation. Detailed analysis reveals that pectin in cocoa pulp largely consists of weakly bound substances, and that both temperature and enzyme activity play a role in its degradation. Furthermore, this study shows that pulp degradation by an indigenous yeast fully relies on the presence of a single gene (PGU1), encoding for an endopolygalacturonase. Apart from their basic scientific value, these new insights could propel the selection of microbial starter cultures for more efficient pulp degradation.