# Comparison of the Chemical and Sensorial Evaluation of Dark Chocolate Bars
## 3 Results and Discussion
### Panel Test

Table 5: Average scores of the panel test (6 untrained panelists) evaluation descriptors for the organic (BIO, 2 samples), hard discount (HD, 8 samples), and supermarket (SM, 14 samples) bars. Organic and supermarket bars were reported as having harder and crunchier snap sounds, while lighter and more mellow sounds were described for the HD bars. The lighter and more mellow sound perceived by the panelists when breaking the HD bars compared to the harder notes reported for the organic and supermarket bars might indicate a higher presence of fats, and especially in their unsaturation degree, since this parameter positively correlated with more unpleasant softness and lack of snap in the final product [34]; on the contrary, a good, high-pitched snap at ambient conditions is a desirable character in chocolate [2]. The reported odor attributes were mainly fruity for all bars; in BIO and SM bars the caramel-like odor followed, while for HD bars the herbaceous odor was the second overall most attributed descriptor. The aroma, perceived in the retro-nasal area once bars were put in the mouth, was quite consistent with their odor perception; high scores for the fruity aroma notes were described for all bars, but BIO bars scored higher in the nutty descriptor, while the caramel-like contribution was attributed more to HD and SM bars. Both odor and aroma negative attributes of dairy and animal-like notes were overall more perceived in HD bars. Fruity notes perceived in all bars can be attributed to the quantitatively relevant presence, in all samples, of 2-phenylethyl acetate, whose aroma contribution is reported as pleasantly sweet and fruity [1; 11; 12]. The more intense herbaceous odor perceived by panelists in HD bars could be ascribed to their overall higher relative content of 2,5-dimethylpyrazine, whose olfactory contribution is described as a \"green\" note [4; 35]. HD bars were also richer in nonanal, a non-terpene aldehyde to which their higher scores in the dairy and animal-like aroma and odor notes can be attributed, since its contribution is reported as \"fatty\" [29]. In both odor and aroma perception, the nutty descriptor was mainly attributed to the HD bars; this might be due to the overall higher relative content of benzaldehyde in HD bars [36]. Aldehydes, in general, are released faster during mastication, as they have less interaction with the oral mucosa [37]. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Descriptors** & **BIO** & **HD** & **SM** \\ \hline \multicolumn{4}{c}{Texture and melting attributes} \\ \hline Smooth (lips) & 4.0 & 4.1 & 3.6 \\ Vlevety (lips) & 1.5 & 1.6 & 1.9 \\ Grainy (lips) & 0.5 & 0.5 & 0.5 \\ Smooth (tongue) & 2.5 & 2.8 & 2.4 \\ Vlevety (tongue) & 3.0 & 3.3 & 2.9 \\ Grainy (tongue) & 0.5 & 0.1 & 0.6 \\ Immediate melting & 1.0 & 2.6 & 1.1 \\ Delayed melting & 5.0 & 3.4 & 4.9 \\ \hline \multicolumn{4}{c}{Taste perception} \\ \hline Bitter taste & 5.0 & 3.4 & 3.5 \\ Sweet taste & 2.0 & 2.8 & 2.4 \\ Salty taste & 0.5 & 0.8 & 0.4 \\ Acidic taste & 0.0 & 1.1 & 1.6 \\ Umami taste & 0.0 & 0.4 & 0.2 \\ \hline \multicolumn{4}{c}{In-mouth sensation} \\ \hline Astringent sensation & 2.0 & 0.9 & 0.9 \\ Burnt sensation & 0.0 & 0.1 & 0.1 \\ Warmth sensation & 1.5 & 1.6 & 1.7 \\ Sparkling sensation & 0.5 & 0.4 & 0.8 \\ Acid sensation & 0.0 & 0.3 & 0.4 \\ Metallic sensation & 0.0 & 0.1 & 0.2 \\ Fatty sensation & 0.0 & 0.6 & 0.4 \\ Oily sensation & 2.0 & 1.6 & 1.1 \\ \hline \hline \end{tabular} Legend for the sample names: organic bars (BIO), supermarket bars (SM), and hard discount bars (HD).  
\end{table} 
Table 5: _Cont._The texture of the chocolate matrix is a result of its particles distribution and size; solid particles over 35 \(\upmu\)m are, indeed, detected by the tongue during mastication, causing a rough and gritty in-mouth perception [2]. Most of the chocolate bars were perceived as smooth on the lips; the textural perception then turned velvety once the product reached the tongue, due to the fat melting triggered by the higher in-mouth temperature.