## 2 Results and Discussion
### Volatile Profile and Composition  
The aroma of cocoa is one of the most influential quality features, as it is key to the acceptability of cocoa beans and cocoa products such as chocolate. To date, more than 600 aromatic compounds have been identified from cocoa beans and chocolate products. These compounds include heterocyclic compounds, acids, aldehydes and ketones, esters, alcohols, hydrocarbons, nitriles and sulfides, pyrazines, ethers, furans, pyrones, phenols, pyrroles, and many others [13]. Table 4 shows the volatile compounds identified in the chocolate samples. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Compound [mg/kg]** & **Blend80** & **Blend90** & **Blend100** & **Madagascar** & **Vietnam** & **Honduras** \\ \hline
**Aldehydes** & & & & & & \\ Isobutyraldehyde & 0.57 & 1.96 & 3.15 & 2.95 & 1.37 & 0.43 \\
3-Methylbutanal & 11.04 & 25.84 & 36.19 & 51.01 & 15.36 & 10.64 \\
2-Methylbutanal & 6.50 & 13.55 & 18.87 & 32.44 & 12.29 & 8.07 \\ Furfural & ND & 8.54 & 6.43 & 6.40 & ND & 2.94 \\ Methional & ND & ND & ND & 8.53 & ND & 1.19 \\ Benzaldehyde & 36.26 & 102.79 & 135.60 & 118.84 & 43.49 & 45.18 \\ Hyacinthin & 31.79 & 56.45 & 118.66 & 118.09 & 52.15 & 40.84 \\ Nonanal & 12.69 & 23.85 & ND & 28.56 & 13.14 & 13.96 \\ Caprinaldehyde & ND & ND & 1.39 & ND & ND & ND \\
2-Phenyl-crotonaldehyde & 0.58 & ND & 5.13 & 1.08 & 3.11 & 2.97 \\
**Alcanes** & & & & & & \\ \(n\)-Hexane & 14.75 & 73.26 & 44.95 & 194.00 & 17.48 & 31.50 \\
2,6-Dimethylnonane & ND & ND & ND & ND & ND & 1.18 \\ Undecane & ND & ND & ND & 11.16 & ND & ND \\ Dodecane & 0.82 & 2.24 & ND & ND & ND & ND \\ Alcohols & & & & & & \\ Ethanol & 0.31 & 1.38 & 1.02 & 1.79 & 1.18 & 0.32 \\
2-Pentanol & 2.23 & 6.48 & 5.62 & 11.92 & 12.70 & ND \\
2,3-Butanediol & 26.15 & 83.94 & 116.90 & 290.34 & 54.86 & 44.47 \\
2,3-Butanediol & 20.37 & 69.77 & 71.25 & 311.54 & 29.87 & 24.32 \\ Furfurylalcohol & ND & 6.11 & 15.34 & ND & ND & 4.66 \\
2-Heptanol & 4.19 & 5.52 & 9.14 & 4.98 & 4.17 & 2.88 \\ Phenylmethanol & 5.31 & 9.90 & 11.45 & 20.73 & 7.29 & 4.18 \\
2-Nonanol & ND & ND & 30.98 & ND & ND & ND \\
2-Phenylethanol & 22.25 & 53.43 & 77.41 & 62.30 & 44.62 & 56.92 \\
2-Buthyl-1-oktanol & 2.00 & 11.67 & 9.32 & ND & ND & ND \\
**Heterocycles** & & & & & & \\ Methylpyrazine & ND & ND & ND & ND & 0.80 \\
2,5-Dimethylpyrazine & 1.99 & 2.50 & 10.18 & 3.62 & 4.42 & 3.61 \\
2,3-Dimethylpyrazine & 2.75 & 8.17 & 8.46 & 15.11 & 2.74 & 3.39 \\
2-Ethyl-6-methylpyrazine & 0.47 & ND & 2.65 & ND & ND & 15.23 \\
2,3,5-Trinethylpyrazine & 15.01 & 31.40 & 43.35 & 81.39 & ND & ND \\
2,6-Dimethyl-3-ethylpyrazine & 0.98 & 6.77 & 6.36 & 4.32 & 2.18 & 3.10 \\ Tetramethylpyrazine & 60.31 & 93.01 & 167.66 & 285.74 & 103.76 & 68.40 \\
2,3,5-Trimethyl-6-ethylpyrazine & 0.80 & 1.34 & 5.07 & 4.00 & 2.44 & ND \\ Toluene & 0.73 & 4.75 & ND & 7.18 & ND & 1.58 \\ _m_-Cymene & 4.10 & 12.79 & 10.95 & 16.44 & 2.64 & 3.23 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: The aroma composition of samples. The predominant compound in all tested samples was acetic acid, varying from 24.78% in sample blend80 to 29.35% of all volatile compounds in sample blend100. Acetic acid in cocoa beans lowers the pH to about 4.5-5.5, which allows enzymatic reactions and subsequent fermentation. Drying and roasting significantly decrease the content of volatile acids, which is one of the prerequisites for the development of a pleasant aroma of the final products. However, if the cocoa beans are dried rapidly, volatile acids are trapped inside the beans, which is undesirable because the high acid content can lead to an unpleasant aroma of both cocoa and chocolate. Low content, on the other hand, may be related to loss of proper chocolate taste [36]. Also, [PERSON] et al. [37] identified acetic acid as the most dominant and most sensory active acid in chocolate samples. The pyrazines are considered the most important group of odorants with chocolate notes [38]. In our samples, tetramethylpyrazine was present in the highest concentrations of pyrazines.