Project description:Fermentation is essential for cocoa flavour development, as during this process key flavour precursors are formed from the degradation of the major cocoa bean storage proteins. This work characterises the peptide and protein profiles of Theobroma cacao beans of the genotype IMC 67 at different fermentation stages, using the Styrofoam box fermentation method and employing UHPLC-ESI MS/MS for the analysis of peptides and proteins extracted from the beans. A total of 1058 endogenous peptides were identified and quantified over four fermentation time points. The majority of these peptides were formed during the early stage of fermentation and originated predominantly from the proteolysis of two storage proteins - vicilin and a 21 kDa albumin. The changes in the peptide profile over fermentation were subsequently evaluated, and potential markers for assessing the degree of fermentation were identified. In particular, changes of the relative abundance of the major cocoa proteins detected can be proposed as potential markers for the fermentation stage. Furthermore, PCA analysis of both the peptidomic and proteomic data has allowed differentiation of beans at different fermentation stages.
