Department of Agricultural, Forest, and Food Sciences, University of Turin, Turin, Italy.
Tecnológico Nacional de México, Instituto Tecnológico de Veracruz, Unidad de Investigación y Desarrollo en Alimentos, Veracruz, Mexico.
Appl Environ Microbiol. 2021 Jun 25;87(14):e0042521. doi: 10.1128/AEM.00425-21.
Microbial metabolism drives changes in the physicochemical properties and, consequently, the sensory characteristics of fermented cocoa beans. In this context, information regarding the structure, function, and metabolic potential of microbial communities' present during cocoa pulp-bean mass fermentation is limited, especially concerning the formation of aromatic compounds. To bridge the gap, the metagenome of fermented cocoa pulp-bean mass (Criollo and Forastero) has been investigated using shotgun metagenomics coupled with physicochemical, microbiological, quality, and sensory analyses to explore the impact of microbial communities on the quality of fermented cocoa pulp-bean mass on one farm in one season and in one region under the same environmental conditions. Our findings showed that the metagenomic diversity in cocoa, the fermentation length, and the diversity and function of metagenome-assembled genomes (MAGs) greatly influence the resulting distinctive flavors. From the metabolic perspective, multiple indicators suggest that the heterolactic metabolism was more dominant in Criollo fermentations. KEGG genes were linked with the biosynthesis of acetic acid, ethanol, lactic acid, acetoin, and phenylacetaldehyde during Criollo and Forastero fermentations. MAGs belonging to Lactiplantibacillus plantarum, Limosilactobacillus reuteri, and Acetobacter pasteurianus were the most prevalent. Fermentation time and roasting are the most important determinants of cocoa quality, while the difference between the two varieties are relatively minor. The assessment of microbiological and chemical analysis is urgently needed for developing fermentation protocols according to regions, countries, and cocoa varieties to guarantee safety and desirable flavor development. Monitoring the composition, structure, functionalities, and metabolic potential encoded at the level of DNA of fermented cocoa pulp-bean mass metagenome is of great importance for food safety and quality implications.
微生物代谢会改变发酵可可豆的理化性质，并由此改变其感官特性。在这种情况下，有关发酵可可豆浆豆块（克里奥罗和福拉斯特罗）中微生物群落结构、功能和代谢潜力的信息有限，特别是在芳香化合物形成方面。为了弥补这一空白，我们使用鸟枪法宏基因组学结合理化、微生物、质量和感官分析，研究了发酵可可豆浆豆块的宏基因组，以探索微生物群落对一个季节、一个地区、一个农场的发酵可可豆浆豆块质量的影响。在相同的环境条件下。我们的研究结果表明，可可的宏基因组多样性、发酵时间以及宏基因组组装基因组（MAGs）的多样性和功能极大地影响了最终的独特风味。从代谢角度来看，多项指标表明，异乳酸发酵在克里奥罗发酵中更为占主导地位。KEGG 基因与克里奥罗和福拉斯特罗发酵过程中乙酸、乙醇、乳酸、乙酰基和苯乙醛的生物合成有关。属于植物乳杆菌、雷特氏乳杆菌和巴氏醋酸杆菌的 MAGs 最为普遍。发酵时间和烘焙是影响可可质量的最重要因素，而两个品种之间的差异相对较小。根据地区、国家和可可品种制定发酵方案，迫切需要进行微生物和化学分析评估，以确保安全和理想的风味发展。监测发酵可可豆浆豆块宏基因组的 DNA 水平上的组成、结构、功能和代谢潜力对于食品安全和质量具有重要意义。
