# Screening Wild Yeast Isolated from Cocoa Bean Fermentation Using Volatile Compounds Profile
## 2 Results and Discussion  
### Yeast Isolation  
A total of one hundred fifty (150) wild yeast strains were isolated from spontaneous cocoa bean fermentations of three localities in Santander, Colombia. The morphological characterization of yeasts showed thirteen different morphotypes (M) (Figure 1); 52% of the strains (21 isolates) were identified at the genus level, while a total of 48% isolates did not match any of the identities given by RapID Yeast Plus System. Four genera of yeasts were identified: _Hanseniaspora_ (_n_ = 9), _Saccharomyces (_n_ = 7), _Pichia_ (_n_ = 5), and _Rlodotulla_ (_n_ = 1).  
Literature review indicates that yeasts composition during the cocoa fermentation process is directly responsible for developing the flavor and aroma of chocolate. A previous work carried out in the same research group that analyzed the VCs present in different cocoa liquors found 24 compounds produced by yeasts, which suggests that some of the compounds produced during fermentation can be maintained despite the roasting process, for example, 3-methyl butyl acetate and 2-phenylmethyl acetate are also present in cocoa liqueurs. After the roasting process, a greater variety of compounds appear due to the oxidation of alcohols, which decreases their concentration with respect to the fermentation process and give rise to the formation of compounds such as aldehydes and ketones, which they increase their variety and concentration in cocoa liquefus. Therefore, it is vitally important to know the compounds produced by yeasts that positively impact the quality of the final product in order to better design the starter inoculum [18].  
The most frequently reported genera in fermentation cocoa in countries, such as Colombia, Brazil, Cuba, Ghana, Indonesia, Dominican Republic, Malaysia and Mexico are _Saccharomyces, Pichia, Hanseniaspora, Kluyveromyces, Hansenula, Wickerhamonyces_ and, _Candida_[12]. For example, a study conducted by [PERSON] et al. [19] identified the species _Wickerhamonyces anomalus_, _Debaryomyces hansenii_, _Meyerozyma guillermondii_, _Pichia Guillermondii_, _Pichia Kudriuzevoi_, _Pichia manshurica_, _Trichosporan ashii_, and _Candida parpsilosis_ from several cocoa fermentation processes in three regions of Colombia. Their results showed that the strains _W. anomalus_, _D. hansenii_, and _M. guillermondii_ were the most  
Figure 1: Isolated and identified yeasts from spontaneous cocoa bean fermentations. M1, morphotype 1; M2, morphotype 2; M3, morphotype 3; M4, morphotype 4; M5. morphotype 5; M6, morphotype 6; M7, morphotype 7; M8, morphotype 8; and M9, morphotype 9.  
promising to be included in a microbial starter culture for cocoa bean fermentation, due to their tolerance of high concentrations of sugars, acidity, and temperature. Experiments lead in Brazil by [PERSON] et al. [20], isolated yeast strains of the genus _Candidia, Hansenispora, Rodhotorula, Saccharomyces, Pichia, Saccharomycopsis_, and _Trichosporon_ during the fermentation of the three cocoa hybrids (pH 9, pH 15, and pH 16). Their results revealed that _S. cerevisiae_ was predominant during fermentation in all experiments, followed by _H. uvarum_ and _Pichia_. In addition, [PERSON] et al. [13], isolated _Saccharomyces cerevisiae_, _Candidia tropicalis_, _Pichia kudriazevii_, _Pichia galeiforms_, _Galactomyces geotrichum_, and _Wickerhamomyces anomalus_. Amount these yeasts found that _P. kudriazevii_, _S. cerevisiae_, _G. geotrichum_, and _W. anomalous_ were the strains that contributed to the formation of cocoa-specific aroma compounds. Therefore, our results are in agreement with previous studies, which confirm that the predominant genera of wild yeast in cocoa fermentation in Colombia are _Saccharomyces_, _Pichia, Hansenispora, Kluyveromyces, Hansenula, Wickerhamomyces_, and _Toruspora_. However, to the best of our knowledge, there are no previous reports associated with the concentration of volatile compounds that can be produced by these strains.