Crafack M.1, Petersen M.A.1, Eskildsen C.E.A.1, Petersen G.B.2, Heimdal H.2 and Nielsen D.S.1
1 Department of Food Science, University of Copenhagen, 1958 Frederiksberg C, Denmark. 2 Toms Confectionary Group A/S, Toms Allé 1, 2750 Ballerup, Denmark.
E-mail: mcrafack@life.ku.dk
Cocoa beans, the principal raw material of chocolate, originate as seeds in fruit pods of the tree Theobroma cacao. Raw cocoa has an astringent, unpleasant taste and flavour and has to be fermented, dried and roasted to obtain the characteristic cocoa flavour and taste. Besides the genetically inherited flavour potential of different cocoa varieties, the fermentation process is regarded as the most important factor influencing the flavour potential of cocoa.
A properly conducted fermentation process is considered a prerequisite for the production of high quality chocolates since inadequately fermented cocoa beans will fail to produce cocoa specific aroma compounds during subsequent processing.
Here, we report a comparative study of the volatile aroma compounds identified in chocolates produced from Forastero type cocoa fermented using two mixed starter cultures, encompassing yeasts with high production of aromatic compounds and high pectinolytic activity, in a small scale tray setup together with commercial scale heap and tray fermented cocoas.
Using a combination of dynamic headspace GC-MS and multivariate data analysis, the impact of starter cultures and different fermentation techniques on the volatile aroma profile of chocolate was evaluated.
Approximately 120 volatile compounds were identified by GC-MS with the major groups of compounds being aldehydes, pyrazines, esters and alcohols. Based on the quality of identification, the peak areas of 57 selected compounds were used to construct PCA models.
The results of the present study indicate that the volatile aroma profile of chocolate can be influenced using selected yeasts and bacteria as inoculation cultures, however the choice of fermentation technique seems to have a greater impact on the aroma profile.
