## 3 Results and Discussion
### Volatile Chemical Compositions of the Experimental Chips
To better understand which ingredient was responsible for the emission of metabolites by the two samples, we performed the analysis using the same technique also on DLF and HSR. The obtained results listed in Table 7 highlight that the two monoterpene compounds limonene and 1,8-cineole are released by lentil flour, and in particular, limonene was the compound found with the higher percentage, in accordance with a previous study [31; 32]. It should be considered that cooking affects the pulses' volatile composition [33], and for this reason, a direct correlation between the obtained data from the experimental chips (Table 6) and the raw DLF (Table 7) was not found. Instead, to the best of our knowledge, this is the first study to investigate the HS volatile composition. A previous study investigated the volatilome composition of raw and roasted whole Tonda Gentile Romana hazelnuts [34]; however, several differences were reported in comparison to our \begin{table}
\begin{tabular}{c c c c c} \hline \hline \(\mathbf{N}^{\circ}\) & **COMPONENT 1** & **LRI 2** & **LRI 3** & **CTRc (\%)** & **HSc5\%** \\ \hline
1 & hexane, 2,4-dimethyl- & 731 & 728 & - & 0.8 \(\pm\) 0.06 \\
2 & heptane, 4-methyl- & 768 & 764 & 0.5 \(\pm\) 0.02 b & 3.5 \(\pm\) 0.04 a \\
3 & hexanal & 807 & 804 & 7.2 \(\pm\) 0.08 \\
4 & heptane, 2,4-dimethyl- & 818 & 821 & 0.1 \(\pm\) 0.01 b & 11.0 \(\pm\) 0.1 a \\
5 & 2,4-dimethyl-1-heptene & 831 & 836 & 1.6 \(\pm\) 0.03 & - \\
6 & octane, 3,5-dimethyl- & 925 & 928 & 1.0 \(\pm\) 0.03 b & 3.8 \(\pm\) 0.05 a \\
7 & octane, 3,3-dimethyl- & 930 & 935 & - & 7.3 \(\pm\) 0.06 \\
8 & \(\alpha\)-pinene & 937 & 941 & 0.1 \(\pm\) 0.01 b & 1.6 \(\pm\) 0.04 a \\
9 & heptane, 4-propyl- & 941 & 945 & 0.2 \(\pm\) 0.02 b & 1.4 \(\pm\) 0.05 a \\
10 & octane, 2,4,6-trimethyl- & 953 & 955 & - & 9.2 \(\pm\) 0.3 \\
11 & decane & 1001 & 1000 & 0.9 \(\pm\) 0.04 & - \\
12 & nonane, 2,6-dimethyl- & 1018 & 1025 & 1.1 \(\pm\) 0.04 & - \\
13 & limonene & 1033 & 1031 & 0.4 \(\pm\) 0.02 b & 1.9 \(\pm\) 0.02 a \\
14 & 1,8-cineole & 1035 & 1033 & 0.3 \(\pm\) 0.02 b & 3.1 \(\pm\) 0.02 a \\
15 & nonanal & 1110 & 1105 & - & 20.1 \(\pm\) 0.08 \\
16 & undecane & 1118 & 1115 & 1.3 \(\pm\) 0.04 & - \\
17 & decane, 2,4,6-trimethyl- & 1124 & 1121 & 0.4 \(\pm\) 0.02 b & 1.3 \(\pm\) 0.03 a \\
18 & L-camphor & 1142 & 1139 & - & 1.3 \(\pm\) 0.04 \\
19 & 3-pinanylamine & 1145 & 1142 & 0.3 \(\pm\) 0.02 & - \\
20 & 5-ethyldecane & 1148 & 1146 & 0.1 \(\pm\) 0.01 & - \\
21 & undecane, 5-methyl- & 1155 & 1156 & 0.1 \(\pm\) 0.01 & - \\
22 & 2,3-dimethyldecane & 1161 & 1158 & 0.7 \(\pm\) 0.02 & - \\
23 & undecane, 3-methyl- & 1173 & 1171 & 1.2 \(\pm\) 0.03 & - \\
24 & dodecane & 1216 & 1214 & 87.4 \(\pm\) 10.12 a & 14.1 \(\pm\) 0.08 b \\
25 & dodecane, 2,6,11-trimethyl- & 1325 & 1320 & 0.8 \(\pm\) 0.02 b & 1.5 \(\pm\) 0.02 a \\
26 & nonane, 2,2,4,4,6,8,8-heptamethyl- & 1331 & 1329 & - & 2.0 \(\pm\) 0.04 \\
27 & farnesan & 1386 & 1381 & 0.5 \(\pm\) 0.02 b & 3.9 \(\pm\) 0.05 a \\
28 & \(\beta\)-copane & 1431 & 1426 & - & 0.5 \(\pm\) 0.02 \\
29 & 2-undecanethiol, 2-methyl- & 1435 & 1433 & - & 3.6 \(\pm\) 0.05 \\
30 & \(\gamma\)-muurolene & 1491 & 1486 & - & 0.8 \(\pm\) 0.02 \\
31 & hexadecane & 1615 & 1612 & 0.7 \(\pm\) 0.02 & - \\ \hline \multicolumn{4}{c}{} \\ \hline \hline \multicolumn{4}{c}{} \\ \hline \hline \end{tabular}  
* The components are reported according to their elution order on apolar column; 2 linear retention indices measured on polar column; 3 linear retention indices from the literature; data are means \(\pm\) standard deviation of three (n = 3) replicates. Means with different letters, in the same row, are significant different according to Student’s \(t\)-test (p < 0.01). CTRc, control chip; HSC5%, hazelnut skin 5% chip.  
\end{table} 
Table 6: Volatile chemical composition (percentage mean value \(\pm\) standard deviation) of CTRc and HSC5%, as determined by HS-SPME/GC–MS. study.