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allied
academies
Archives of Industrial Biotechnology | Volume 2
May 14-15, 2018 | Montreal, Canada
World Yeast Congress
C
ocoa research performed during the last century has
elucidated the basic physiology and ecology of cocoa
fermentation and the biochemical changes that occur during
cocoa fermentation, drying and roasting that lead to the
development of the chocolate flavour. Biotechnological
manipulation of the steps of microbial fermentation
(microorganisms, amount of pulp, selected strains) can result
in understandable and reasonably predictable effects on
chocolate quality. Many different species of microorganisms
have been isolated from cocoa fermentation and have
been characterised and the microbial succession has been
defined. Yeast are essential to the fermentation process and
development of chocolate flavour. The concept of using starter
cultures to conduct cocoa bean fermentations is not new.
Initially, around 1960-1980, the aim was to induce a faster,
more consistent fermentation, without adverse impact on
chocolate quality. More specific investigations on the use of
starter cultures have nowbeen conductedwhere themain goals
have been to develop a faster, more consistent fermentation
process that yields cocoa beans with predicable qualities.
The dynamic of
Saccharomyces cerevisiae,
P
ichia kluyveri and
Hanseniaspora
uvarum
during spontaneous and inoculated
cocoa fermentations and their effect on sensory characteristics
of chocolate were investigated. Yeast populations were
assessed by qPCR. S. cerevisiae was predominant during
spontaneous (average 5.4 log cell/g) and inoculated (average
7.2 log cell/g) fermentations. The
H. uvarum
seemed to be
suppressed by the other two yeasts, as it showed similar
population (approximately 4.0 log cell/g) even in the inoculated
assay. Carbohydrates were consumed quickly at inoculated
fermentation (68% and 42% were consumed in the inoculated
and control assays respectively, at 24 h). Ethanol content was
higher in the inoculated (8.3 g/kg at 48 h) than in the control
(4.6 g/kg at 96 h) fermentation. Chocolate produced from
the spontaneous fermentative process presented dominance
of the bitter flavour, while obtained through inoculated
fermentation process presented bitter, astringent, coffee
and acid as dominant flavours. The inoculation accelerated
the fermentative process in 48 h. The inoculation of yeast
influenced the microbial profile, which affected the volatile
compounds that affect sensory characteristics, resulting in
chocolate with dominant bitter, cocoa, and fruity attributes.
e:
rschwan@dbi.ufla.brImprovement of chocolate flavor by yeast during cocoa fermentation
Rosane Freitas Schwan
Universidade Federal de Lavras, Brazil