Industrial Bioprocessing and Bioremediation By Haikle Lee Ning ID: 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 Topics 1. 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 Summary Cocoa 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 Background Cocoa 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 Papers Both 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 Comments A 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 1. Lima, et.al. (2012). Microbiota Dynamics and Diversity at Different Stages of Industrial Processing of Cocoa Beans into Cocoa Powder. Applied and Environmental Microbiology, 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,