Yeasts are essential for cocoa bean fermentation

Ho, Van Thi Thuy, Zhao, Jian and Fleet, Graham (2014) Yeasts are essential for cocoa bean fermentation. International Journal of Food Microbiology, 174 72-87. doi:10.1016/j.ijfoodmicro.2013.12.014

Author Ho, Van Thi Thuy
Zhao, Jian
Fleet, Graham
Title Yeasts are essential for cocoa bean fermentation
Journal name International Journal of Food Microbiology   Check publisher's open access policy
ISSN 0168-1605
Publication date 2014-03-17
Sub-type Article (original research)
DOI 10.1016/j.ijfoodmicro.2013.12.014
Open Access Status Not yet assessed
Volume 174
Start page 72
End page 87
Total pages 16
Place of publication Amsterdam, Netherlands
Publisher Elsevier
Language eng
Formatted abstract
Cocoa beans (Theobroma cacao) are the major raw material for chocolate production and fermentation of the beans is essential for the development of chocolate flavor precursors. In this study, a novel approach was used to determine the role of yeasts in cocoa fermentation and their contribution to chocolate quality. Cocoa bean fermentations were conducted with the addition of 200 ppm Natamycin to inhibit the growth of yeasts, and the resultant microbial ecology and metabolism, bean chemistry and chocolate quality were compared with those of normal (control) fermentations. The yeasts Hanseniaspora guilliermondii, Pichia kudriavzevii and Kluyveromyces marxianus, the lactic acid bacteria Lactobacillus plantarum and Lactobacillus fermentum and the acetic acid bacteria Acetobacter pasteurianus and Gluconobacter frateurii were the major species found in the control fermentation. In fermentations with the presence of Natamycin, the same bacterial species grew but yeast growth was inhibited. Physical and chemical analyses showed that beans fermented without yeasts had increased shell content, lower production of ethanol, higher alcohols and esters throughout fermentation and lesser presence of pyrazines in the roasted product. Quality tests revealed that beans fermented without yeasts were purplish-violet in color and not fully brown, and chocolate prepared from these beans tasted more acid and lacked characteristic chocolate flavor. Beans fermented with yeast growth were fully brown in color and gave chocolate with typical characters which were clearly preferred by sensory panels. Our findings demonstrate that yeast growth and activity were essential for cocoa bean fermentation and the development of chocolate characteristics.
Keyword Cocoa bean fermentation
Lactic acid bacteria
Acetic acid bacteria
Cocoa quality
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Agriculture and Food Sciences
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Created: Tue, 07 Mar 2017, 10:08:12 EST by Van Ho on behalf of School of Agriculture and Food Sciences