## 4 Conclusions  
In conclusion, here, we showed that addition of hazelnut skin from the Romana variety to a dehulled lentil-based snack allows a nutritional profile improvement, increasing the fiber content by 33.5% and maintaining a high protein content (24.03 g/100 g), in addition to a significant TPC and TAC increase in comparison to control (1.6- and 2-times increase, respectively). Furthermore, hazelnut skin from the Romana variety can improve the sensory profile of the lentil-fortified chips, attenuating pulse-like and potato attributes and earning the fortified snack a higher overall judgment score by the official sensorial panelists (6.844 of the fortified snack in comparison to 5.611 of the control, on a 0-10 scale). The volatile chemical composition analysis revealed a strong decrease in the dodecane compound, with a gasoline-like odor, in HSc5% compared to CTRc. Finally, for the first time, the hazelnut skin volatile composition was investigated, highlighting its peculiar volatile chemical profile, which differs from previous data reported in the literature relating to whole Romana hazelnuts. Therefore, hazelnut skin could be a valuable ingredient in improving the nutritional and functional features of bakery products as well as the sensory profiles of less palatable but healthy legume-based foods. It is worth noting that using hazelnut skin as a by-product of the industrial processing of hazelnuts plays an important role in environmental sustainability and the global agricultural economy. \begin{table}
\begin{tabular}{c c c c c} \hline
**N\({}^{\circ}\)** & **COMPONENT 1** & **LRI 2** & **LRI 3** & **DLF (\%)** & **HSR (\%)** \\ \hline
1 & hexanal & 810 & 812 & - & 61.4 \(\pm\) 1.10 \\
2 & 2,2,5,5-tetramethylhexane & 865 & 870 & 1.9 \(\pm\) 0.03 & - \\
3 & 3-butenyl pentyl ether & 978 & 982 & - & 1.7 \(\pm\) 0.03 \\
4 & heptane, 2,2,4,6,6-pentamethyl- & 981 & 985 & - & 5.8 \(\pm\) 0.05 \\
5 & _cis_-\(\beta\)-coincene & 1020 & 1024 & 11.5 \(\pm\) 0.12 & - \\
6 & limorene & 1028 & 1031 & 22.1 \(\pm\) 0.14 & - \\
7 & 1,8-cineole & 1030 & 1033 & 7.5 \(\pm\) 0.08 & - \\
8 & _trans_-\(\beta\)-ocimene & 1035 & 1034 & 7.0 \(\pm\) 0.03 & - \\
9 & \(\beta\)-terpinene & 1037 & 1036 & 2.1 \(\pm\) 0.08 & - \\
10 & _n_-propyl l repyl ether & 1080 & 1075 & - & 27.3 \(\pm\) 0.25 \\
11 & 2,6,8-trimethyl-decane & 1110 & 1104 & 4.0 \(\pm\) 0.03 & - \\
12 & isothujol & 1115 & 1110 & - & 1.7 \(\pm\) 0.07 \\
13 & 1,3,8-p-mentatriene & 1120 & 1118 & 3.3 \(\pm\) 0.02 & - \\
14 & 2,5,9-trimethyldecane & 1122 & 1121 & 4.2 \(\pm\) 0.04 & - \\
15 & 2,4,6-trimethyldecane & 1124 & 1122 & 11.5 \(\pm\) 0.08 a  & 2.0 \(\pm\) 0.02 b  \\
16 & 2,5,9-trimethyldecane & 1126 & 1123 & 3.8 \(\pm\) 0.04 & - \\
17 & pentonic acid, hydrazide & 1159 & 1161 & 2.0 \(\pm\) 0.02 & - \\
18 & 6-ethyl-2-methyldecane & 1191 & 1185 & 4.3 \(\pm\) 0.03 & - \\
20 & ylangene & 1380 & 1376 & 4.7 \(\pm\) 0.02 & - \\
21 & 2,6,10,14-tetramethylheptadecane & 1876 & 1872 & 9.9 \(\pm\) 0.07 & - \\ \hline \multicolumn{5}{c}{SUM} & 99.8 & 99.9 \\ \hline \end{tabular}  
* \({}^{1}\) 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). DLF, dehulled lentil four; HSR, hazelnut skin Romana.  
\end{table} 
Table 7: Volatile composition (percentage mean value \(\pm\) standard deviation) of lentil flour and hazelnut film, as determined by HS-SPME/GC–MS. **Author Contributions:** Conceptualization, L.C. ; methodology, L.C., M.T.F., and S.G.; software, L.C., M.T.F., and S.G.; validation, L.C., R.M., and N.M.; formal analysis, L.C., M.T.F., and S.G.; investigation, L.C., M.T.F., and S.G.; resources, L.C. and N.M.; data curation, L.C., M.T.F., and S.G.; writing--original draft preparation, L.C.