## 3 Results and Discussion
### Volatile Organic Compounds  
Volatile profiles are generated by complex biochemical processes derived from the hydrolysis or metabolism of carbohydrates, proteins, and fats, along with compounds added during processing or directly from the milk due to the activity of LAB [45]. VOCs were identified in cheese samples and GPP by SPME-GC/MS technique (Table 4). A total of 21 VOCs were detected in GPP, whereas 21 and 14 VOCs were identified in cheese samples with and without GPP addition, respectively. Volatile compounds belonging to alkanes, aldehydes, monoterenes, esters, acids, and ketones were identified in all cheese samples. Acetic acid and 2-hydroxy4-methyl pentanoic acid were the most abundant acids detected in cheese sample without GPP addition. Acetic acid may be \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Chemical Compounds 1 ** & \multicolumn{6}{c}{**Samples**} \\ \cline{2-10}  & **GPP** & **CCh\({}_{15}\)36** & **ECh\({}_{15}\)36** & **CCh\({}_{15}\)94** & **ECh\({}_{15}\)94** & **CCh\({}_{15}\)169** & **ECh\({}_{15}\)169** & **CCh\({}_{15}\)190** & **ECh\({}_{15}\)190** \\ \hline Acids & & & & & & & & \\ Acetic acid & n.d. & 9.5 & 16.2 & 14.1 & 14.9 & 9.2 & 11.8 & 18.7 & 10.4 \\ Butanoic acid & n.d. & 9.2 & 7.5 & 10.9 & 7.4 & 5.7 & 5.7 & 9.0 & 6.0 \\
4-Hydroxybutanoic acid & 4.1 & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. \\ Hexanoic acid & 1.6 & 5.9 & 5.0 & 8.2 & 4.3 & 4.3 & 4.0 & 7.1 & 4.3 \\ Pentanione & n.d. & 16.0 & 2.5 & 12.2 & 7.2 & 8.0 & 5.2 & 13.0 & 4.7 \\ acid-2-hydroxy-4-methyl & 3.4 & n.d. & 0.5 & n.d. & 0.3 & n.d. & 0.2 & n.d. & 0.4 \\
3-Methylbutanoic acid & 3.4 & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. \\ Ketons & & & & & & & & & \\
2-Pentanone & n.d. & 2.8 & 0.6 & 2.4 & 0.7 & 1.8 & 0.6 & 2.3 & 0.5 \\
2-Heptanone & n.d. & 2.0 & 0.5 & 1.9 & 0.7 & 2.2 & 0.6 & 2.4 & 0.5 \\ p-Phenylacetophenone & 4.2 & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. \\ Alcohol & & & & & & & & & \\ Isoamyl alcohol & 4.9 & 23.7 & 42.3 & 27.8 & 50.0 & 44.3 & 51.6 & 21.5 & 59.9 \\
2-Pentanol & n.d. & n.d. & 0.4 & n.d. & 0.2 & n.d. & 0.2 & n.d. & 0.8 \\
2-Butanol & n.d. & 1.3 & 0.5 & 1.4 & 0.5 & 1.7 & 0.6 & 2.3 & 0.2 \\
2-Phenylethanol & 11.3 & n.d. & 2.6 & n.d. & 2.3 & n.d. & 3.9 & n.d. & 2.7 \\ Hydrocarbons & & & & & & & & & \\ Hexane 2-methyl & n.d. & n.d. & 0.3 & n.d. & 0.5 & n.d. & 0.3 & n.d. & 0.3 \\ Heptane 2,4-dimethyl & 3.2 & 12.2 & 3.4 & 5.6 & 3.2 & 9.5 & 4.6 & 8.5 & 5.1 \\ Octane 4-methyl & n.d. & 4.4 & 0.5 & 1.8 & 0.5 & 3.6 & 0.6 & 2.5 & 0.3 \\ Nonane & 2.2 & n.d. & 0.4 & n.d. & 0.5 & n.d. & 0.7 & n.d. & 0.4 \\ Nonane 2,5-methyl & 2.3 & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. \\ Decane & 1.8 & n.d. & 0.4 & n.d. & 0.3 & n.d. & 0.5 & n.d. & 0.2 \\ Dodecane & 2.3 & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. \\ Hexadecane & 1.7 & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. \\ Aldeyde & & & & & & & & & & \\ Hexanal & 3.2 & 2.6 & 0.2 & 1.7 & 0.4 & 2.0 & 0.2 & 2.8 & 0.2 \\ Heptanal & n.d. & 1.9 & 0.5 & 1.9 & 0.4 & 1.8 & 0.1 & 2.5 & 0.2 \\ Nonanal & 1.7 & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. \\ Monoterpene & & & & & & & & & \\ Phellandrene & n.d. & 1.8 & n.d. & 2.5 & n.d. & 1.9 & n.d. & 2.4 & n.d. \\ D-Limonene & 6.3 & n.d. & 12.7 & n.d. & 2.1 & n.d. & 5.0 & n.d. & 0.5 \\ \(\alpha\)-Pinene & 2.1 & 6.7 & 2.6 & 7.6 & 3.1 & 4.1 & 2.6 & 5.0 & 1.9 \\ Carene & 1.5 & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. \\ Estre & & & & & & & & & & \\ Octanione acid, ethyl & & & & & & & & & & \\ ester & & & & & & & & & & \\ Detanioic acid, diethyl & & & & & & & & & \\ ester & & & & & & & & & & \\ Decanoic acid, ethyl & & & & & & & & & & \\ ester & & & & & & & & & & & \\ Diol & & & & & & & & & & \\
2,3-Butanediol & 20.6 & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. & n.d. \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Volatile organic compounds emitted from cheeses.