## 3 Results
### Minor Volatiles in Functional Katiki Domokou-Type Cheese  
Katiki Domokou-type cheese samples fortified with free or immobilized _P. acidilactici_ ORE5 cells on pistachio nuts were evaluated regarding their volatile compounds at the beginning and after 3 days of refrigerated storage by the HS-SPME GC/MS technique, and the results are presented in Table 6. For comparison reasons, Katiki Domokou cheese samples with no _P. acidilactici_ ORE5 cells were also analyzed. Overall, 41 compounds were detected: 14 compounds in the KC sample, 27 compounds in the KFP sample and 37 compounds in the KIP sample. The main classes of volatile compounds identified were esters, acids, alcohols, and carbonyl compounds. From a quantitative perspective, the highest (\(p<0.05\)) content of total volatiles was observed in the KFP sample (52.3 \(\mu\)g/g), while total volatiles were ranged from 31.6 \(\mu\)g/g in the KIP sample and 4.8 \(\mu\)g/g in the KC sample. More specifically, the incorporation of free _P. acidilactici_ ORE5 cells in cheese resulted in significantly (\(p<0.05\)) higher amounts of total esters, acids and hydrocarbons, while the cheese sample fortified with immobilized _P. acidilactici_ ORE5 cells contained higher concentrations of total alcohols (\(p<0.05\)). Regarding total carbonyl compounds, no significant differences were observed between KFP and KIP samples. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Cheese 1**} & \multirow{2}{*}{**Days of Storage**} & \multicolumn{2}{c}{**Total Aerobic Count (TAC)**} & \multicolumn{2}{c}{**Psychrophilic Bacteria**} & \multicolumn{2}{c}{**Lactococci**} & \multicolumn{2}{c}{**Lactobacillus11**} & \multicolumn{2}{c}{**Years**} & \mul  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline
**Cheese \({}^{1}\)** & **Days of Storage** & \begin{tabular}{c} **Total Aerobic Count (TAC)** \\ **doger(Og)** \\ \end{tabular}  & \begin{tabular}{c} **Psychophilic Bacteria** \\ **(loger(Og))** \\ \end{tabular}  & \ \begin{tabular}{c} **Lactocoeci** \\ **loger(Og)** \\ \end{tabular}  &
\begin{tabular}{c} **Lactobacillus** \\ **(loger(Og))  
The detected volatile compounds in cheese samples included seven esters. Among them, ethyl acetate, ethyl hexanoate and 2-phenylethyl acetate were identified in all cheese samples. However, the incorporation of free or immobilized _P. acidilactici_ ORE5 cells led to significantly (\(p<0.05\)) increased amounts of these compounds compared to the control sample. Of note, ethyl propanoate, ethyl butyrate, 3-methylbutyl acetate and ethyl decanoate were detected only in the KFP and KIP samples. Among the volatile compounds, five acids were detected in cheese samples. Sorbic, octanoic, benzoic and decanoic acid were present in all samples, while hexanoic acid was found in the KFP and KIP samples after 3 days of storage. In general, the amounts of acids were higher (\(p<0.05\)) in the KFP and KIP samples than in the control cheese (KC). In total, six alcohols were detected in the samples. Amounts of 3-methyl-1-butanol and 2-phenylethanol were identified in all samples; however, higher concentrations were observed in the KFP and KIP samples (\(p<0.05\)) compared to the control cheese. Of note, 2-methyl-1-propanol and 2-methyl-1-butanol were present only in KFP and KIP, while 1-hexanol and 2-methyl-phenol were detected only in the KIP sample. In all cases, the incorporation of immobilized cells in cheese led to the highest concentrations of alcohols (\(p<0.05\)) among the samples. The carbonyl compounds present in cheese samples included 6 aldehydes and 4 ketones that were more abundant in the KFP and KIP samples than in KC. Among them, only hexanal was common in all samples. In the KC sample, 2-pentanone and 2-heptanone were the only carbonyl compounds detected, apart from hexanal. 2-nonanone was observed only in the KFP sample, while heptanal was present at the beginning of storage in KFP cheese; however, it was undetectable after 3 days of storage.