# Screening Wild Yeast Isolated from Cocoa Bean Fermentation Using Volatile Compounds Profile
## 2 Results and Discussion
### Identification and Quantification for Volatile Compounds (VC's)
The most abundant compounds found in the esters family were 3-methyl butyl acetate (317.1846 mg/kg), 2-phenyl ethyl acetate (276.7966 mg/kg), and ethyl acetate (102.0740 mg/kg). Between  
Figure 3: Mass spectra for peak 3-methyl butyl acetate. (**a**) Scan of experimental analysis; (**b**) scan spectrum analysis founded on NIST database and fragmentation pattern. Figure 2: GC-MS chromatogram of the volatile compounds produced by yeast Y111. Peak A is 3-methyl butyl acetate and peak B is 2-phenylmethyl acetate. them, the 2-phenyl ethyl acetate (2-PEA) is an interesting phenolic aroma compound in cocoa bean fermentation due to its floral, fruity, and honey-like aroma. The chemical production of 2-PEA is derived from the availability of 2-PE, which is its precursor. This VC is obtained from the esterification of 2-PE with acetic acid and through the transesterification of 2-PE with acetate esters [25]. Amount yeasts, _Hanseniaspora_ stands out for being a genus with more efficiency to produce 2-PEA [9; 26]. In the case of 3-methyl butyl acetate, its production can be explained by the esterification of 3-methyl butanol by yeasts. On the other than, the synthesis of ethyl- acetate depends on the ethanol concentration. In addition, 3-methyl butyl acetate or isoamyl acetate, 2-phenyl ethyl acetate, and ethyl acetate are considered markers of sensory quality in cocoa fermentation [26] and therefore, the isolated yeasts in this study seem to have esters production potential that improve cocoa beans' sensorial qualities. Our results showed the formation of acetic acid, an important contributor to the aroma of unroasted cocoa seeds that were formed during fermentation by action enzymatic degradation of the fruit pulp [27]. Of the pyrazines, two compounds were identified. It is known that pyrazines in cocoa beans are originated from the Strecker degradation in Maillard reactions during the roasting of cocoa beans [22]. However, in this study, two pyrazines were identified in the samples tested. It should be noted that pyrazines are not a family of compounds commonly found during fermentation, however, certain studies have reported that it is possible to find them and they are not exclusively produced during cocoa roasting [18]. On the other hand, in the present study three compounds were identified (2-pentanol, \(\alpha\)-terpineol, 2,4-di-tert-butylphenol) that had not been reported in similar studies but that correspond to metabolites that can be produced by yeasts. Thus, for example, \(\alpha\)-terpineol is a metabolite related to floral aromas associated with lilacs (Table 2). This could be produced thanks to the enzyme monoterpene synthase (MTS) in the early stages of the formation of ergosterol, which is a structural compound of yeast _Saccharomyces cerevisiae_[28]. Indeed a study conducted by [PERSON], (2000) revealed the ability of _Saccharomyces cerevisiae, Kluyveromyces lactis_ and _Torulaspora delbrueckii_ to convert monoterpencids. These yeasts demonstrated the greatest number of reactions, between them, the conversion of nerol and linalool to \(\alpha\)-terpineol [29].