Transformaciones bioquímicas asociadas a la calidad de algunos grupos genéticos de cacao (Theobroma cacao L.) mediante un proceso de fermentación controlada
Fecha
2020
Autores
Rojas Rojas, Katherine Vanessa
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Editor
Universidad Nacional, Costa Rica
Resumen
La fermentación de cacao es un proceso de gran importancia para la formación de características
aromáticas y sensoriales del cacao. El estudio de la diversidad de microorganismos involucrados
en la fermentación ha sido ampliamente estudiado. Se concluye que levaduras, bacterias ácido
lácticas y ácido acéticas son las responsables del consumo de los compuestos disponibles en la
pulpa. A su vez, se desencadenan reacciones enzimáticas y no enzimáticas que desarrollan los
precursores de sabor dentro del grano. Sin embargo, la fermentación de cacao es difícil de controlar
debido a la complejidad del proceso y la multitud de variables, entre las cuales es determinante la
genética del cultivo. Por lo tanto, el objetivo de esta investigación fue analizar las transformaciones
bioquímicas asociadas a la calidad de diferentes grupos genéticos del cacao (T. cacao L.) mediante
un proceso de micro fermentación controlada. Para ello, se estableció una metodología de micro
fermentación, utilizando un cultivo iniciador de Hanseniaspora opuntie aplicado a las 0 h y
Acetobacter spp. a las 48h, en incubadoras. Se empleó esta metodología en cacaos provenientes
de 4 grupos genéticos cultivados en el Jardín Clonal del CATIE; así como el paquete tecnológico
implementado por el CATIE e híbridos de diferentes fincas de la zona de Upala. Se analizaron
azúcares (glucosa y fructosa), etanol, ácido láctico y acético en pulpa; así como metilxantinas
(teobromina y cafeína) y (-)-epicatequina en grano a lo largo de la fermentación, como indicadores
de la evolución fermentativa. En ambos ensayos (grupos genéticos del CATIE y cacaos
comerciales de la zona Upala) no se encontraron diferencias significativas en el contenido y
comportamiento de azúcares, ácidos orgánicos y etanol en pulpa de los genotipos estudiados, a lo
largo de la fermentación, pero sí en el tiempo de fermentación. Se observó una disminución de
metilxantinas y epicatequina debido a la difusión y oxidación desencadenadas por reacciones
enzimáticas y no enzimáticas. El contenido promedio de epicatequina de fermentación resultó ser
el compuesto distintivo entre los grupos genéticos del CATIE, y cafeína en los cacaos comerciales.
Se concluye que la metodología empleada posee un efecto regulador en el comportamiento de
azúcares, ácidos orgánicos y etanol en pulpa de diferentes genéticas a lo largo de la fermentación,
así como epicatequina y metilxantinas en grano. Se determinó que las variables climáticas, así
como agronómicas tienen un gran peso en el comportamiento de metilxantinas y epicatequina de
los diversos genotipos a lo largo de la fermentación. Los resultados de esta tesis apuntan a un
primer esfuerzo en la identificación de diferencias determinadas por la genética del cacao en el
diseño de tecnologías de fermentación experimental para la producción de cacao con calidad
controlada.
Cocoa fermentation is a process of great importance for the formation of aromatic and sensory characteristics of cocoa. aromatic and sensory characteristics of cocoa. The study of the diversity of microorganisms involved in fermentation has been extensively in fermentation has been extensively studied. It is concluded that yeasts, lactic acid and acetic acid and acetic acid bacteria are responsible for the consumption of the compounds available in the pulp. pulp. In turn, enzymatic and non-enzymatic reactions are triggered that develop flavor precursors within the grain. flavor precursors within the bean. However, the fermentation of cocoa is difficult to control due to the complexity of the process the complexity of the process and the multitude of variables, among which the genetics of the crop is a determining factor. genetics of the crop. Therefore, the objective of this research was to analyze the biochemical transformations associated with the quality of cocoa beans. associated with the quality of different genetic groups of cocoa (T. cacao L.) by means of a controlled micro fermentation process. a controlled micro fermentation process. For this purpose, a microfermentation methodology was fermentation methodology was established, using a starter culture of Hanseniaspora opuntie applied at 0 h and Acetobacter spp. at 0 h and Acetobacter spp. at 0 h. Acetobacter spp. at 48h, in incubators. This methodology was used on cocoa from 4 genetic groups grown in incubators. from 4 genetic groups cultivated in the Clonal Garden of CATIE, as well as the technological package implemented by CATIE and hybrids from different farms in the Upala area. Sugars (glucose and sugars (glucose and fructose), ethanol, lactic and acetic acid in pulp, as well as methylxanthines (theobromine and theobromine). (theobromine and caffeine) and (-)-epicatechin in the bean throughout fermentation, as indicators of fermentation evolution. of fermentation evolution. In both trials (CATIE genetic groups and commercial cocoa in the Upala area), no significant differences were found in the content In both trials (CATIE genetic groups and commercial cocoa from the Upala area), no significant differences were found in the content and behavior of sugars, organic acids and ethanol in the pulp of the genotypes studied throughout fermentation, but there were significant differences in fermentation time. A decrease in methylxanthines and epicatechin was observed due to diffusion and oxidation triggered by enzymatic and non-enzymatic reactions. The average fermentation epicatechin content was found to be the distinguishing compound among the CATIE genetic groups, and caffeine in commercial cocoas. It is concluded that the methodology employed has a regulating effect on the behavior of sugars, organic acids and ethanol. sugars, organic acids and ethanol in pulp of different genetics throughout fermentation, as well as epicatechin and methylxanthines in grain. It was determined that climatic and agronomic variables have a great and agronomic variables have a great weight in the behavior of methylxanthines and epicatechin of the different genotypes throughout the the different genotypes throughout fermentation. The results of this thesis point to a first effort the identification of differences determined by cocoa genetics in the design of experimental fermentation technologies for the the design of experimental fermentation technologies for the production of quality-controlled cocoa. controlled quality.
Cocoa fermentation is a process of great importance for the formation of aromatic and sensory characteristics of cocoa. aromatic and sensory characteristics of cocoa. The study of the diversity of microorganisms involved in fermentation has been extensively in fermentation has been extensively studied. It is concluded that yeasts, lactic acid and acetic acid and acetic acid bacteria are responsible for the consumption of the compounds available in the pulp. pulp. In turn, enzymatic and non-enzymatic reactions are triggered that develop flavor precursors within the grain. flavor precursors within the bean. However, the fermentation of cocoa is difficult to control due to the complexity of the process the complexity of the process and the multitude of variables, among which the genetics of the crop is a determining factor. genetics of the crop. Therefore, the objective of this research was to analyze the biochemical transformations associated with the quality of cocoa beans. associated with the quality of different genetic groups of cocoa (T. cacao L.) by means of a controlled micro fermentation process. a controlled micro fermentation process. For this purpose, a microfermentation methodology was fermentation methodology was established, using a starter culture of Hanseniaspora opuntie applied at 0 h and Acetobacter spp. at 0 h and Acetobacter spp. at 0 h. Acetobacter spp. at 48h, in incubators. This methodology was used on cocoa from 4 genetic groups grown in incubators. from 4 genetic groups cultivated in the Clonal Garden of CATIE, as well as the technological package implemented by CATIE and hybrids from different farms in the Upala area. Sugars (glucose and sugars (glucose and fructose), ethanol, lactic and acetic acid in pulp, as well as methylxanthines (theobromine and theobromine). (theobromine and caffeine) and (-)-epicatechin in the bean throughout fermentation, as indicators of fermentation evolution. of fermentation evolution. In both trials (CATIE genetic groups and commercial cocoa in the Upala area), no significant differences were found in the content In both trials (CATIE genetic groups and commercial cocoa from the Upala area), no significant differences were found in the content and behavior of sugars, organic acids and ethanol in the pulp of the genotypes studied throughout fermentation, but there were significant differences in fermentation time. A decrease in methylxanthines and epicatechin was observed due to diffusion and oxidation triggered by enzymatic and non-enzymatic reactions. The average fermentation epicatechin content was found to be the distinguishing compound among the CATIE genetic groups, and caffeine in commercial cocoas. It is concluded that the methodology employed has a regulating effect on the behavior of sugars, organic acids and ethanol. sugars, organic acids and ethanol in pulp of different genetics throughout fermentation, as well as epicatechin and methylxanthines in grain. It was determined that climatic and agronomic variables have a great and agronomic variables have a great weight in the behavior of methylxanthines and epicatechin of the different genotypes throughout the the different genotypes throughout fermentation. The results of this thesis point to a first effort the identification of differences determined by cocoa genetics in the design of experimental fermentation technologies for the the design of experimental fermentation technologies for the production of quality-controlled cocoa. controlled quality.
Descripción
Licenciatura en Ingeniería Agronómica
Palabras clave
CACAO, COCOA, FERMENTACIÓN, FERMENTATION, FITOMEJORAMIENTO, PLANT BREEDING, MEJORAMIENTO GENÉTICO, GENETIC IMPROVEMENT