Diversity and determinants of bitterness, astringency, and fat content in cultivated Nacional and native Amazonian cocoa accessions from Ecuador

Abstract

Cocoa (Theobroma cacao L.) is the only tree that can produce cocoa. Cocoa beans are highly sought after by chocolate makers to produce chocolate. Cocoa can be fine aromatic, characterized by floral and fruity notes, or it can be described as standard cocoa with a more pronounced cocoa aroma and bitterness. In this study, the genetic and biochemical determinants of sensorial notes and nonvolatile compounds related to bitterness, astringency, fat content, and protein content will be investigated in two populations: a cultivated modern Nacional population and a population of cocoa accessions collected recently in the Ecuadorian South Amazonia area of origin of the Nacional ancestral variety. For this purpose, a genome-wide association study (GWAS) was carried out on both populations, with results of biochemical compounds evaluated by near-infrared spectroscopy (NIRS) assays and with sensory evaluations. Twenty areas of associations were detected for sensorial data especially bitterness and astringency. Fifty-three areas of associations were detected linked to nonvolatile compounds. A total of 81 candidate genes could be identified in the areas of the association. INTRODUCTIONCocoa (Theobroma cacao L.

Collection of native Theobroma cacao L. accessions from the Ecuadorian Amazon highlights a hotspot of cocoa diversity

“…As a result of these surveys, this work has allowed the preservation and collection of genetic material close to the Nacional control group, known for its aromatic qualities and of importance for Ecuadorian cocoa production. The aromatic potential of the collected accessions is currently being analyzed (Colonges, Loor Solorzano, et al, 2022; Colonges, Seguine, et al, 2022). The enrichment of the allelic diversity of the Nacional varieties should provide, within the framework of improvement programs, to have material adapted to the local growing conditions found in the Ecuadorian Amazonian regions surveyed.…”

Inoculum of a Native Microbial Starter Cocktail to Optimize Fine-Aroma Cocoa (Theobroma cacao) Bean Fermentation

“…The assimilation of citric acid by microorganisms causes the pH to increase [24]. The degree and time of acidification of the cotyledon during the fermentation process [25] together with changes in temperature, generated by a succession of various microorganisms (yeasts, LAB, AAB, and Bacillus sp. ), create an optimal environment inside the cocoa bean for enzymes such as endoprotease, carboxypeptidase, invertase, and glycosidase to catalyze reactions that generate flavor precursor substances [26,27].…”

“…Our values were lower than those reported by [15], who found 44.29 GA mg/g DM on the first day of fermentation, decreasing to 36.78 GA mg/g DM on the last day for Nacional cacao. The low polyphenol content may be due to the harvest time and plant age; however, low polyphenol contents result in chocolates that are less astringent and bitter [25,26].…”