The impact of pod storage on the formation of different alkylpyrazines from Ghanaian cocoa roasted at four roasting temperatures

The impact of pod storage on the formation of different alkylpyrazines from Ghanaian cocoa roasted at four roasting temperatures

Ann De Winne, Michael Hinneh, Julie Haeck, Davy Van de Walle, Jim Van Durme, Emmanuel Ohene Afoakwa, Koen Dewettinck, Luc De Cooman

The typical flavour characteristics of cocoa are related to the cocoa bean genotype and the growing environmental conditions. However, the flavour does not exist in freshly harvested beans. Flavour is generated by a series of procedures that begins with occasional pod storage (PS) after harvesting, followed by fermentation of the beans, and roasting. PS implies storing harvested cocoa pods for a period of time before opening. The effect of PS is believed to be beneficial for the subsequent development of cocoa flavour in the cocoa beans [1]. During roasting, several volatile heterocyclic compounds are formed, among them alkylpyrazines. These newly formed compounds are considered to be key odour components. Among alkylpyrazines, tetramethylpyrazine and trimethylpyrazine, are the most abundant ones. Other alkylpyrazines with different substituents also contribute to the aroma profile. Hence, monitoring pyrazines can be helpful in optimizing roasting conditions of cocoa beans for attaining the desired aroma of the cocoa liquors. In several studies, cocoa volatiles have been measured using gas chromatography mass spectrometry (GC-MS), frequently using headspace solid-phase microextraction (HS-SPME) to concentrate the volatiles.
The purpose of this study was to investigate the effect of PS (0, 3, 7 days PS) and roasting temperature (100 C, 120 C, 140 C and 160 C) on the formation of alkylpyrazines in Ghanaian cocoa liquors. HS-SPME extraction of the alkylpyrazines was carried out with a DVB/CAR/PDMS fibre. The identified compounds were measured semiquantitatively and the results were statistically processed by multivariate …

Verlag der Technischen Universität Graz

2018

https://scholar.google.com/citations?view_op=view_citation&hl=en&user=EZuX1N8AAAAJ&cstart=100&pagesize=100&citation_for_view=EZuX1N8AAAAJ:edV_OwlUe4UC

English