## 3 Results and Discussion
### Volatile Compounds Analysis
Alcohols, primarily produced through lipid oxidation [28], play a crucial role in ham flavor, contributing herbaceous, woody, and fatty notes [29]. Alcohols with sweet, fruity, or onion and mushroom-like odors are notable in this group [30]. Phenylethyl alcohol (A8), found in all samples, is significant for its aromatic floral and fruity notes [31]. Research indicates that phenylethyl alcohol (A8) levels were low at three months during the ripening period, but increased after 12 months [1, 31, 32], which could explain its varying levels among the samples. In this study, SXZH, with a 36-month maturation period, exhibited the highest concentration of phenylethyl alcohol (A8) (875.16 \(\pm\) 2.92 ng/g), aligning with previous findings that extended ripening enhances the accumulation of such compounds. BHCH, despite a shorter maturation, showed relatively high levels (337.77 \(\pm\) 2.71 ng/g), which may be attributed to its specific processing conditions, such as controlled temperature and humidity during cellar aging, potentially accelerating proteolysis and the subsequent formation of phenylethyl alcohol (A8) [33, 34]. Compounds like 1-octen-3-ol (A3) and 1-octanol (A7) have low odor thresholds and significantly impact the aroma profile [35]. Herein, 1-octen-3-ol (A3), known for its strong mushroom aroma, was the most abundant alcohol detected in FZWH (4414.67 \(\pm\) 13.68 ng/g) and is commonly found in meat products such as Istrian dry-cured ham [1]. 1-Octanol (A7), which imparts fatty, sharp aroma notes [35], was present in BHCH, SXZH, and FZWH. Benzyl alcohol (A9), contributing floral notes [36], was detected in BHCH, LTWH, and FZWH. Notably, BHCH and FZWH, the most expensive and least \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**No.**} & \multirow{2}{*}{**Compound**} & \multirow{2}{*}{**Retention**} & \multirow{2}{*}{**CAS**} & \multicolumn{5}{c}{**Concentration (ng/g)**} \\ \cline{5-8}  & & & & **BHCH \({}^{*}\)** & & **SXZH \({}^{\text{b}}\)** & **FXZH \({}^{*}\)** & **LTWH \({}^{\text{d}}\)** & **FZWH \({}^{*}\)** \\ \hline \multicolumn{8}{c}{**Terpenses**} \\ \hline \multirow{4}{*}{G1} & \multirow{4}{*}{\
\begin{tabular}{c} Naphthalene, 1,2,4a,5,8,8a-hexah-to- \\ methylylethyl-,1(5- \\ (1.alpha,_a_beta_a_delta_alpha_beta_).] \\ \end{tabular} } & \multirow{4}{*}{44.45} & \multirow{4}{*}{523-47.7} & \multirow{4}{*}{n.d.} & \multirow{4}{*}{n.d.} & \multirow{4}{*}{n.d.} & \multirow{4}{*}{\(69.43\pm 0.06\)} & \multirow{4}{*}{\(2.72\pm 0.36\)} & \multirow{4}{*}{n.d.} \\ \cline{1-1} \cline{5-8}  & & & & & & & \\ \hline G2 & D-Limonene & 15.94 & 5989-27.5 & n.d. & n.d. & n.d. & \(137.35\pm 0.57\) & \(393.57\pm 3.12\) \\ \hline \multirow{4}{*}{G3} & \multirow{4}{*}{
\begin{tabular}{c} Naphthalene, 1,2,3,5,6,8a- \\ healthy/dro-4,7-dimethyl- \\ 1-(1-methylylethyl), \\ (15-cis-) \\ \end{tabular} } & \multirow{4}{*}{44.43} & \multirow{4}{*}{483-76-1} & \multirow{4}{*}{n.d.} & \multirow{4}{*}{n.d.} & \multirow{4}{*}{n.d.} & \multirow{4}{*}{n.d.} & \multirow{4}{*}{76.42\(\pm\) 3.68} \\ \cline{1-1} \cline{5-8}  & & & & & & & \\ \hline H1 & 2,6-Dimethylpyrazole & 10.44 & 108-50.9 & 160.84 \(\pm\) 2.97 & 583.44 \(\pm\) 3.59 & 484.21 \(\pm\) 1.41 & 87.81 \(\pm\) 0.59 & 197.42 \(\pm\) 1.91 \\ \hline H2 & Furan, 2,5-pentyl- & 14.04 & 377-69-3 & n.d. & 8534.15 \(\pm\) 24.7 & n.d. & n.d. \\ \hline H3 & Pyrazine, tetramethyl- & 18.84 & 1124-11-4 & n.d. & n.d. & 87.7 \(\pm\) 1.75 & n.d. & n.d. \\ \hline H4 & Dimethyl trisulfide & 12.83 & 3658-80-8 & n.d. & n.d. & 75.52 \(\pm\) 1.00 & n.d. & n.d. \\ \hline \hline \end{tabular}  
* BHCH: Black Hoof Cured Ham. \({}^{\text{b}}\) SXZH: Superior-grade Xuan-Zi Ham. \({}^{\text{c}}\) FXZH: First-grade Xuan-Zi Ham. \({}^{\text{d}}\) LTWH: Liang-Tou-Wu Ham. \({}^{\text{e}}\) FZWH: Fei-Zhong-Wang Ham. \({}^{\text{f}}\) n.d. not detected.  
\end{table} 
Table 4: _Cont._  
Figure 5: Venn diagram of volatile compounds in five different types of ham samples. A: BHCH, B: SXZH, C: FXZH, D: LTWH, E: FZWH.