## 2 Results and Discussion
### Volatile Fraction Analysis
\begin{table}
\begin{tabular}{l c c c c c c c c c c c c c c c c c c c c} \hline  & \multicolumn{1}{c}{**Compound**} & \multicolumn{1}{c}{**LRL\({}_{\text{ex}}\)**} & \multicolumn{1}{c}{**LRL\({}_{\text{lib}}\)  
Volatile organic compounds (VOC) are commonly correlated with food flavor and fragrance, and their determination is important to evaluate food quality, authenticity, purity, and origin [9]. Methyl and ethyl esters, for example, provide strong fruity notes in foods, whereas terpen provide woody, floral, fruity, and spicy notes. Aldehydes have a low odor threshold, and the sniffing analysis of _Capsicum_ reported their presence as green, cucumber, pungent, or herbaceous odor notes [10; 11]. In addition, it has been proven that the volatiles' profile of _Capsicum_ is mainly affected by varieties [5], ripening stages [3], and processing [12]. The analyses carried out on _Capsicum chinense_ peppers revealed that the most relevant compounds are esters (4-methylpentyl 3-methylbutanoate, 6-methylhept-4-en-1-yl 3-methylbutanoate, 4-methylpentyl 2-methylbutanoate, hexyl 3-methylbutanoate, (Z)-3-hexenyl 2-methylbutanoate, 2-methylbutyl 8-methylon-6-enoate, 6-methylhept-4-en-1-yl 2-methylbutanoate, heptyl isovalerate, 4-methylpentanoate, 6-methylheptyl 3-methylbutanoate, and (Z)-3-hexenyl 3-methylbutanoate) (Figure 1). The presence of several aliphatic esters in the _C. chinense_ variety has been reported in the literature [3; 4; 5; 6]; it has been confirmed that esters, especially straight-chain esters, are generally metabolized from fatty acids through oxidation [13], and that branched saturated and non-saturated esters can be derived from amino acids' metabolism [5]. Among the analyzed _C. chinense_ samples, Habanero red savina, Habanero chocolate, and Scotch bonnet showed a lower content of esters and a greater amount of alcohols and aldehydes (Figure 4). It has been demonstrated that ester biosynthesis is limited by alcohol concentration, which can modify the content of esters in specific cultivars [14]. In the analyzed species, even if there is good alcohol availability, the production of the esters is probably inhibited by the absence of free fatty acids. Literature data on the _Capsicum Chinese_ variety [3; 4] report the presence of a little amount of 2-isobutyl-3-methoxypyrazine in the Habanero peppers variety (0.01 mg kg\({}^{-1}\)). Effectively, the three Habanero chili peppers analyzed in the present study did not present this compound (Habanero fatali (sample 3) and Habanero red savina (sample 7)), or had a very little quantity (Habanero chocolate (sample 8) (0.06%)) of 2-isobutyl-3-methoxypyrazine, which was mainly detected in the Scotch Bonnet variety (sample 9) (0.52%). The volatile profile of the analyzed _Capsicum annuum_ samples was principally characterized by acids, in particular acetic; aldehydes ((_E_)-2-hexenal, \(n\)-hexanal, 2-methylbutraldehyde,  
Figure 4: Distribution of volatile compounds’ class identified in the analyzed samples. and isovaleric aldehyde); ketones (acetoin and 3-methyl-2-butanone); alcohols (4-methyl-1-pentanol and isoprenol); and esters (4-methylpentyl 3-methylbutanoate and 4-methylpentyl 2-methylbutanoate) (Table 2 and Table S1 and Figures 2 and 4). Terenzio and Calabrian pepper varieties showed a greater abundance of (\(E\))-2-hexenal than the others belonging to the same species. Only the Jalapeno pepper contained 6-Methylhept-4-en-1-yl 2-methylbutanoate and 6-Methylhept-4-en-1-yl 3-methylbutanoate. Banana and the Jalapeno chili pepper showed the highest amount of acids, followed by Cayenna impala, Terenzio, and Calabrian varieties. Regarding alcohols, the Calabrian pepper is the only one distinguished by a great percentage of (\(E\))-3-hexenol (8.99%). Concerning terpenoids, the Banana pepper showed the highest amount of (\(E\))-\(\beta\)-ocimene, which is absent in the Calabrian pepper. The latter, however, has a higher content of \(\alpha\)-longipinene, which is absent in Banana and Cayenna pepper varieties.