Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 2/2/2008
Publication Date: 9/1/2008
Citation: Irish, B.M., Goenaga, R.J., Santiago, S., Seguine, E. 2008. Development of a Micro-fermentation process for cacao germplasm evaluation. Proceedings Undergraduate Research Program. Livestock and Environmental Group, Faculty of Agricultural Sciences. University of Puerto Rico, Mayaguez, PR. p.7-17 Interpretive Summary: Cacao seed ‘beans’ must be fermented prior to making chocolate to acquire its characteristic flavor. A number of factors, including plant type and fermentation process contribute to the development of ‘good’ chocolate. The current USDA ARS TARS cacao germplasm collection is being evaluated for agronomic traits of importance; however no data on chocolate quality has been collected. Traditional fermentation is not feasible due to the small number of trees for each plant type and the large volume of cacao beans required for the process. In an effort to further characterize individual cacao types for the chocolate quality produced, a micro-fermentation procedure is being evaluated. Results have shown that temperatures for the micro-fermentation procedure are similar to those reported in traditional fermentation procedures. In addition, examination of the seed shows that complete fermentation was achieved and chocolate quality became much smoother, cleaner, with less acidic and astringent taste following micro-fermentation for 7 days.
Technical Abstract: Cacao (Theobroma cacao) has long been hailed for its primary product, chocolate. Cacao seed ‘beans’ must be fermented prior to making chocolate to acquire its characteristic flavor. The flavor developed from cacao beans varies considerably, and is influenced largely by genetics of the specific cultivar being grown and the fermentation process. The current cacao germplasm collection, maintained at the USDA ARS TARS, consists of 154 accessions with six trees per accession. Although agronomic traits of importance are presently being collected, no data on fermentation and chocolate quality has previously been gathered. Traditional ‘sweat box’ fermentation is not feasible due to the small number of trees for a given accession and the large volume of cacao beans needed. In an effort to further characterize individual accessions for the quality of chocolate produced, a micro-fermentation procedure is being tested. An experiment was conducted with representative accessions of each of three major cacao types (Forastero, Trinitario, and Amelonado) with three different fermentation time intervals (3, 5 and 7 days). Preliminary results have shown that temperature profiles had a mean high temperature of 43.3°C generally between the 3rd and 5th day of fermentation. Cut tests of cacao beans for the 3- and 5-day treatments indicated an incomplete fermentation, whereas the 7 day treatment showed complete fermentation of the beans. The 3-day fermentation treatment resulted in the production of highly astringent chocolate. As the number of fermentation days increased, chocolate quality became much smoother, cleaner, with less acidic and astringent taste and with softer fruit flavors. Overall, as days of fermentation increased so did the quality of the fermented beans, in addition temperature profiles were comparable to reported values for traditional ‘sweat box’ fermentation.