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Tipo de material : bachelorThesis
Título : Caracterización molecular de la microbiota cultivable presente durante las etapas de fermentación comercial de cacao fino y de aroma variedades nacional y trinitario CCN- 51
Autor : Romero Atiencia, Tatiana Gissel
Tutor : Yánez Mendizábal, Viviana del Rocío
Palabras clave : BIOLOGÍA MOLECULAR;FERMENTACIÓN;LEVADURA;CACAO
Fecha de publicación : 2020
Editorial : Quito: Universidad de las Américas, 2020
Citación : Romero, T. (2020). Caracterización molecular de la microbiota cultivable presente durante las etapas de fermentación comercial de cacao fino y de aroma variedades nacional y trinitario CCN (Tesis de pregrado). Universidad de las Américas, Quito.
Resumen : El cacao, es uno de los recursos agrícolas de significativa importancia en el mercado nacional e internacional debido a que constituye la materia prima indispensable para la elaboración del chocolate y otros derivados...
Descripción : Cocoa is one of the agricultural resources of significant importance in the national and international market because it constitutes the essential raw material for the production of chocolate and other derivatives. In Ecuador, the cocoa from the National and Trinitarian CCN-51 fine varieties is the one with the highest worldwide demand for its aroma and flavor qualities. The quality of these varieties depends mainly on the agronomic qualities and post-harvest handling, especially during the fermentation stage. Although a wide range of studies has described the biology of fermentation, linked to the interactions of the cocoa mass with the diversity and dynamics of the microbiota and the variation of the surrounding factors, there are few descriptions for the fine varieties of Ecuador. In this context, the objective of the present study was to characterize the microbiota present during the stages of fermentation of fine and aroma cocoa varieties Nacional and Trinitario CCN-51. The characterization of the microorganisms that predominate according to the cocoa varieties may contribute to the improvement of quality. For the study, cocoa samples from commercial scale production processes in the province of Ríos, Ecuador were used. These were collected and transported to the laboratory for microbiological, biochemical and molecular analysis. The microorganisms present in each variety and stage of fermentation were isolated, purified and preliminarily characterized in selective media for yeasts, lactic and acetic bacteria. The identification of these microorganisms at the genus level was carried out by observing the macro and microscopic characteristics of the different isolates and microchemical A plus B biochemical tests. The results obtained were that in both varieties the most predominant genera of yeasts were Saccharomyces, Acetobacter and Pichia. In national cocoa, 10 genera were found, and in CCN-51 cocoa, 13 genera. Once the samples were identified, molecular characterization was performed by means of PCR amplification and subsequent sequencing. Previously, PCR was standardized for both yeast and bacteria, the DNA used in the two cases was diluted to 20ng out up ul. For molecular identification in yeast, primers ITS1 and ITS4 were used and the ITS region was amplified, and for bacteria, the 16S region was amplified 10 and primers 16 sd and 16 sr were used. The results of the PCR and sequencing analysis showed that the most predominant species in CCN-51 cocoa were Saccharomyces cerviceae and Pichia manshurica, and the most predominant species in national cocoa were Acetobacter ghanensis and Saccharomyces cerviceae. In CCN-51 cocoa, 11 species of yeast and 12 of bacteria were found, while in national cocoa, 13 species of yeast and 4 species of bacteria were found. Therefore, greater microbiological diversity was determined in CCN-51 cocoa.
URI : http://dspace.udla.edu.ec/handle/33000/12703
Aparece en las colecciones: Ingeniería en Biotecnología

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