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Project

Evaluation of the effects of pod storage and roasting on Ghanaian cocoa and chocolate quality

The flavor characteristics of cocoa are highly relevant for its market (economic) value as well as the overall acceptability of the end-chocolate product. For this reason ‘fine’ flavor cocoa is highly valued and priced over ‘bulk’ flavor cocoa, due to its acclaimed unique and desirable flavor attributes. Meanwhile, the latter alone accounts for over 95% of the total global cocoa supply. This presents an opportunity for exploring means by which the flavor of ‘bulk’ cocoa can be improved in order to be able to meet the ever-growing consumer demand. Through studies, we understand that, apart from these varietal differences, huge differences in flavor can also be achieved through the various processing steps (from tree to bar). Thus, from this study, the impacts of pod storage, fermentation and roasting on the dynamics (in both formation and the expression) of different flavor compounds in cocoa and chocolates were investigated.

Pod storage contributed to a variation in both bean acidification and flavor precursor formation. These differences in flavor – which could be clearly perceived in both liquor and the final chocolates – were in consequence of the extent of pulp modification associated with the different pod storage treatments. Whereas prolonged pod storage resulted in a more acidic and intense cocoa flavored chocolate, no or short duration of pod storage yielded chocolates with more fruity/floral and mild cocoa flavor attributes. More so, the fermentation and roasting of cocoa beans could be associated with higher volatile fractions (with respect to the number and concentration of volatiles). Although in terms of volatile formation, the impacts of these processes were of a higher magnitude compared to that of pod storage, their interactions with pod storage (especially pod storage with roasting temperature) played a huge role in the diversification of the flavor profiles of the cocoa beans. Here, the different combinations resulted in different flavor patterns, of which some were highly likened to ‘fine’ flavor chocolates from some renowned origins. The study therefore provides evidence to substantiate the key role(s) of various post-harvest and processing techniques in ‘unlocking’ the flavor potential of cocoa beans. Further, it unravels the possibility of tailoring the flavor of chocolate to suit different palates through processing.

The flavor of chocolate is not only tied to the aforementioned processing steps, more so, it is highly dependent on the specific equipment and techniques applied during the manufacturing process. In this study, the application of the Cocoa Melanger and Stephan mixer in a small-scale alternative chocolate production proved promising. Despite differences in the processing equipment/technique, chocolates with comparable quality attributes were obtained in reference to a conventional chocolate. Although slight differences in aroma profiles could be detected among the chocolates, these differences did not affect consumers’ preference for the different representative chocolates. Thus, the findings substantiate the possibility of creating high quality chocolates through small-scale alternative means.

Date:12 Jan 2017 →  15 Sep 2020
Keywords:Cocoa, Chocolate, Aroma volatiles, Flavor
Disciplines:Biomaterials engineering, Biological system engineering, Biomechanical engineering, Other (bio)medical engineering, Environmental engineering and biotechnology, Industrial biotechnology, Other biotechnology, bio-engineering and biosystem engineering, Food sciences and (bio)technology
Project type:PhD project