## 3 Results and Discussion
### PCA and OPLS-DA Analysis of Volatile Compounds
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Volatile Compounds** & **Odor Description** & **VIP** & **FC(IBW/FBW)** & **FC(FBW/IBW)** \\ \hline
1-pentanol & balsamic & 1.22924 & \(\infty\)* & 0 \\ \(\beta\)-caryophyllene & wood, spice & 1.22741 & 3.73 & 0.27 \\ isopentanol & whiskey, malt, burnt & 1.20884 & \(\infty\) & 0 \\
3,3-dimethyl-1,2- & & 1.20727 & 0.13 & 7.45 \\ epoxybutane & & 1.17866 & 0.55 & 1.80 \\ ethyl acetate & pineapple, overripe & 1.17866 & 0.55 & 1.80 \\ ethyl octanoate & fruit, fat & 1.1774 & 2.87 & 0.35 \\ cis-3-nonen-1-ol & cucumber & 1.17538 & 0.32 & 3.16 \\ cis-3-hexen-1-ol & green & 1.17054 & 0 & \(\infty\) \\ ethyl nonanoate & fruit, flower & 1.15655 & 2.67 & 0.37 \\
2-methoxy-1,3-dioxolane & & 1.15386 & 0.06 & 16.25 \\ ethyl decanoate & grape & 1.13974 & 2.78 & 0.36 \\
1-terpinen-4-ol & wood, turpentine, nutmeg & 1.13623 & 0 & \(\infty\) \\ diethyl succinate & wine, fruit & 1.13137 & 0.42 & 2.39 \\ hexadecane & & 1.12445 & \(\infty\) & 0 \\
3-methyl-1-butanol acetate & banana & 1.12155 & \(\infty\) & 0 \\ \(\gamma\)-nonalactone & coconut, peach & 1.11397 & 0 & \(\infty\) \\ ethyl benzoate & chamomile, flower, celery, fruit & 1.10583 & 0 & \(\infty\) \\
2-phenylethyl alcohol & honey, spice, rose, lilac & 1.07205 & 0.63 & 1.58 \\ octanoic acid & sweat, cheese & 1.05611 & 0.09 & 10.97 \\ propanoic acid & pungent, rancid, soy & 1.03633 & 18.13 & 0.06 \\
2-methyl-1-pentanol & & 1.00204 & 0.56 & 1.77 \\ \hline \hline \end{tabular}  
* \(\infty\), not detected in the other group of samples. FC, fold change.  
\end{table} 
Table 3: Volatile compounds screened out by variable importance in projection (VIP) value of OPLS-DA analysis. compared to a previous study, as 1-pentanol and isopentanol were only detected in IBW. 1-Pentanol is described as having a balsamic flavor and fused oil taste; it contributes to the taste and aroma of wines by balancing the flavor profile and improving the overall sensory experience of wine. It has been reported that the content of 1-pentanol gradually increased during the storage of NFC Chinese bayberry juice [18]. Isopentanol, a common higher alcohol in wine, can add a fruity, floral note to the flavor of wine in small amounts, and may exhibit unpleasant off-flavors at higher concentrations. However, due to the relatively low concentration of 1-pentanol and isopentanol, they should have little negative impact on the sensory properties of IBW. High levels of ethyl acetate and octanoic acid were an important characteristic of FBW. Ethyl acetate representing a pineapple or overwire flavor is a key contributor to the aroma of fermented alcoholic beverages and bayberry wine. On the other hand, the levels of ethyl octanoate (fruit and fat flavor), ethyl nonanoate (fruit and flower flavor), and ethyl decanoate (grape flavor) were more than two times higher in IBW than in FBW, contributing to the better fruity flavor of IBW compared to FBW. Interestingly, it was observed that the non-flavor compound 3, 3-dimethyl-1, 2-epoxybutane was present at a higher level in FBW, 7.45 times higher than that in IBW. This compound has been reported to be produced by bacteria and exhibits strong inhibitory activity against _Aspergillus flavus_[20]. The higher concentration in FBW might indicate that similar microorganisms were present during bayberry wine fermentation. Further investigation is needed to fully understand the mechanism behind the generation of this compound.