Industrial Bioprocessing and Bioremediation

By Haikle Lee NingID: 3225 1081

Website Presentation: Microbiota Dynamics and Diversity in

fermentation of cocoa beans

Table of Contents•Overview•Title of Topics•Executive Summary•Background•Summary of Paper 1•Summary of Paper 2•Comparison of Papers•Comments•References

Title of Topics1. Microbiota Dynamics and Diversity at

Different Stages of Industrial

Processing of Cocoa Beans into Cocoa

Powder

2. Species Diversity, Community

Dynamics and Metabolite Kinetics of

the Microbiota Associated with

Traditional Ecuadorian Spontaneous

Cocoa Bean Fermentations

Table of Contents•Overview•Title of Topics•Executive Summary•Background•Summary of Paper 1•Summary of Paper 2•Comparison of Papers•Comments•References

Executive SummaryCocoa beans are fermented

and manufactured to produce chocolate. Fermentation process is critical in the flavor and stability of the resultant chocolate. Microbiota dynamics and diversity are investigated to improve the two factors mentioned.

Table of Contents•Overview•Title of Topics•Executive Summary•Background•Summary of Paper 1•Summary of Paper 2•Comparison of Papers•Comments•References

BackgroundCocoa beans originates from the fruit

seeds of tropical tree Theobroma cacao L.

The beans are fermented and

manufactured in industrial plants to

produce chocolate. This genetically

inherent cocoa bean flavor is released and

developed in the fermentation process. It

is impossible to improve the genetic

factor and hence the microbiota dynamics

and diversity in fermentation processes

are important to ensure quality chocolate.

Table of Contents•Overview•Title of Topics•Executive Summary•Background•Summary of Paper 1•Summary of Paper 2•Comparison of Papers•Comments•References

Summary(Paper 1)A cocoa powder production line was

sampled and classical microbiological and

polymerase chain reaction based

approaches were used to understand the

microbial composition at different stages of

cocoa bean processing. It was concluded

that the microbiota of cocoa powder from

microorganisms are initially present in the

unprocessed cocoa beans. Bacillus subtilis

formed the most heat-resistant spores and

is essential to ensure the stability of

derived cocoa powder.

Table of Contents•Overview•Title of Topics•Executive Summary•Background•Summary of Paper 1•Summary of Paper 2•Comparison of Papers•Comments•References

Summary(Paper 2)Traditional Ecuadorian

fermentation carried out in boxes and on

platforms were investigated via culture-

dependent and -independent

microbiological analyses. It was observed

that acetic bacteria were not always

present in the main stages of

fermentations. Short fermentation time

and spreading of cocoa beans had

negative impact on the optimal activities

of microbial involved and hence on the

resultant chocolate flavor.

Table of Contents•Overview•Title of Topics•Executive Summary•Background•Summary of Paper 1•Summary of Paper 2•Comparison of Papers•Comments•References

Comparison of PapersBoth papers are investigating on the

influence of microbial activity in cocoa bean

fermentation. The role of yeast and bacteria

involved are explored. The two papers differs in

the methods employed. Paper 1 uses only

culture-dependent method compared to paper

2. Traditional fermentation method is used in

paper 2 and industrial fermentation method is

used in paper 1. Both papers established the

importance of microbiota dynamics and

diversity. Paper 2 achieved more progress

compared to Paper 1. The difference in

methods used result in the different progress

and conclusion drawn.

Table of Contents•Overview•Title of Topics•Executive Summary•Background•Summary of Paper 1•Summary of Paper 2•Comparison of Papers•Comments•References

CommentsA lot of progress were achieved in Paper 2,

it was suggested no interruption during

fermentation and a longer fermentation

time up to 144 hours achieved a better

quality of cocoa beans. A potential new

yeast species which is Candida

sorbosivorans-like was obtained and it is

possible that the yeast could also impact

the quality of cocoa beans produced.

These researches are important to provide

fermented cocoa beans of excellent

quality and further investigation of the

new yeast species can be carried out.

Table of Contents•Overview•Title of Topics•Executive Summary•Background•Summary of Paper 1•Summary of Paper 2•Comparison of Papers•Comments•References

References1. Lima, et.al. (2012). Microbiota

Dynamics and Diversity at Different Stages of Industrial Processing of Cocoa Beans into Cocoa Powder. Applied and Environmental Microbiology , 2904-2913.

2. Papalexandratou, et al. (2011). Species Diversity, Community Dynamics,and Metabolite Kinetics of the Microbiota Associated with Traditional Ecuadorian Spontaneous Cocoa Bean Fermentations. Applied and Environmental Microbiology , 7698-7714.