## 3 Results and Discussion
### Volatile Profile
\begin{table}
\begin{tabular}{l c c c c c c c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**H- Un Unproposed Reses**} & \multicolumn{3}{c}{**H- Unproposed Reses**} & \multicolumn{3}{c}{**H- Unproposed Reses**} & \multicolumn{3}{c}{**H- Unproposed Reses**} & \multicolumn{3}{c}{**H- Unproposed Reses**} \\  & **NC+** & **OMM** & **SIM** & **NC+** & **OMM** & **SIM** & **SIM** & **SIM** & **SIM** & **SIM** & **SIM** & **SIM** & **SIM** & **SIM** \\ \hline  &  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c} \hline \hline \multicolumn{1}{c}{**in-Unpaired Rem**} & \multicolumn{6}{c}{**in-Unpaired Rem**} & \multicolumn{6}{c}{**in-4 months of Repoints**} & \multicolumn{6}{c}{**in-5 months of Repoints**} \\ \hline  & **Max** & **Max** & **Max** & **Max** & **Max** & **Max** & **Max** & **Max** & **Max** & **Max** & **Max** & **Max** & **Max** \\  
Many differences were detected among the three treatments tested. Samples treated with only sodium chloride (NC series) were those represented by the highest amounts of VOCs, associated to the highest increase until the final sampling time as well. Particularly, in the NC series we detected a substantial presence of alcohols and ketones (Table 4), distinctive specifically for this treatment. According to [PERSON] et al. [42] and [PERSON] et al. [43], who studied microbial metabolites in chilled fish, the formation of ketones in high levels, mainly represented by 3-hydroxy-2-butanone (also known as acetoin), can be associated to the active growth of specific spoilage organisms (SSO). Actually, acetoin is a microbial derived compound that can be formed from carbohydrate sources (via pyruvate and diacetyl), generally found in higher amounts if compared to lipid-derived ketones [44]. In this study, 3-hydroxy-2-butanone was found exclusively in NC samples, starting from t2 (6.55 Log peak area). The same was observed for 3-methyl-1-butanol, detected only in NC samples and significantly increasing (\(p<0.01\)) from t2 (2.98 Log peak area) to t3 (6.26 Log peak area). Even 3-methyl-1-butanol has been previously noticed to increase by authors who investigated the volatile profile of fish products and fish roes during cold storage [29; 32; 33; 45]. Particularly, [PERSON] et al. [46] identified the presence of 3-methyl-1-butanol in sterile fish muscle inoculated with spoilage bacteria strains and incubated for 7 days, thus advising the formation of this alcohol by microbial spoilage. For this reason, 3-hydroxy-2-butanone and 3-methyl-1-butanol have been suggested as early indicators of spoilage in fish products. According to this, we found that NC samples were associated with the highest values of TVC detected, even closer to the critical value of 6 Log UFC/g (Table 2). As a matter of fact, even during low temperature storage, both enzymatic and non-enzymatic changes in fish tissues persist, and, even if in slower rates, they can still support microbial growth and metabolism [47]. Moreover, it is known that the use of no additive other than sodium chloride (in low concentrations) makes cavair suitable for consumption only in a relatively short time term (up to 6-8 months) [9] and with a storage temperature close to 0 \({}^{\circ}\)C. NaCl is known to have the power to reduce the autocatalytic activity in food products, but, when it is used as unique method of preservation without further processing, complete bacterial protection is not provided, because halophilic microorganisms can cause spoilage [35]. Thus, in such concentrations (\(<\)4%), it seemed to be not enough to sustain a strong antimicrobial activity alone. The opposite condition was observed in the OAM series, which was represented by the lowest amount of VOCs, and showed a slower and more gradual increase throughout the ripening time. Actually, many compounds representative in NC and BSM samples were undetected in the OAM series. An example is represented by the unsaturated aldehydes 2-heptenal and 4-heptenal.