Yeasts as Producers of Flavor Precursors during Cocoa Bean Fermentation and Their Relevance as Starter Cultures: A Review

Abstract

During the fermentation of cocoa beans, the yeasts produce volatile organic compounds (VOCs). Through reactions associated with amino acid metabolism, yeasts generate important aroma precursors as acetate esters and fatty acid ethyl esters are essential in developing fruity flavors and aromas in the final product (usually chocolate). In addition, some yeasts may have pectinolytic and antifungal activity, which is desirable in the post-harvest process of cocoa. The main yeast species in cocoa fermentation are Saccharomyces cerevisiae, Pichia kudriavzevii, and Hanseniaspora opuntiae. These produce higher alcohols and acetyl-CoA to make acetate–esters, compounds that produce floral and fruity notes. However, there are still controversies in scientific reports because some mention that there are no significant differences in the sensory characteristics of the final product. Others mention that the fermentation of cocoa by yeast has a significant influence on improving the sensory attributes of the final product. However, using yeasts as starter cultures for cocoa bean fermentation is recommended to homogenize sensory attributes such as notes and flavors in chocolate.

Changes in GC-MS metabolite profile, antioxidant capacity and anthocyanins content during fermentation of fine-flavor cacao beans from Ecuador

“…In general, the dynamic of main volatiles was defined by the degradation of aldehydes, and sulfurs from the start of fermentation, the formation of organic acids, amines, esters, and ketones from second day to the following days of fermentation, as well as the persisting presence of alcohols and hydrocarbons during the entire fermentative process. The production of alcohols, esters, and ketones have been mainly attributed to yeasts [42], and derived from fatty acids, amino acids or esterification reactions [13,44]. Ketones mainly provide fruity and floral odor attributes while alcohols contribute to desirable floral and sweet notes which is characteristic of high-quality fermented cacao beans.…”

The contribution of fungi to the global economy

“…These fruity volatile compounds include aldehydes, esters, fatty acids, higher alcohols, organic acids, phenols and sulphur-containing compounds (Carvalho 2016). The main yeasts involved in cocoa fermentation are Hanseniaspora opuntiae, Pichia kudriavzevii, and S. cerevisiae, which produce higher alcohols and acetyl-CoA to make acetate esters that give floral and fruity aromas (Gutiérrez-Ríos et al 2022). Other yeasts found in cocoa formation that produce aromas are Galactomyces Galactomyces geotrichus and Wickerhamomyces anomalus (Koné et al 2016).…”

Spatial Distribution of Cocoa Quality: Relationship between Physicochemical, Functional and Sensory Attributes of Clones from Southern Colombia

“…At the clone level, CCN-51, FSA-11 and FSA-12 were found to be associated with very astringent flavor characteristics, possibly due to high concentrations of polyphenols [48]. These concentrations of polyphenols, when reacting with sugar and amino acids, contribute to the flavor, aroma and color of cocoa beans, and alkaloids contribute to bitterness [92], which can probably impact the clone. To reduce astringency levels, proper management must be performed during the aerobic phases of fermentation, since oxygen-mediated reactions occur in that process, such as the oxidation of protein-polyphenol complexes formed in the anaerobic phase [93].…”