# The Volatile Compounds Change during Fermentation of _Saccharina japonica_ Seedling
## 3 Results
### Qualitative and Quantitative Analysis of Volatile Compounds before and after Fermentation  
A total of 43 volatile compounds were detected in the unfermented _S. japonica_ seedling, including 6 alcohols, 10 aldehydes, 10 ketones, 4 alkanes, 8 alkenes, 3 esters, and 2 other compounds (Table 1). As shown in Table 1, aldehydes and ketones are the most abundant compounds, followed by alkenes and alcohols. Among the aldehydes, 1-nonanal and hexanal are the most abundant in concentration. Ketones are the second most abundant  
Figure 1: A spider diagram illustrating the sensory characteristics of the _S. japonica_ seedling before and after fermentation (SJS) refers to the _S. japonica_ seedling without fermentation. FSJS is the _S. japonica_ seedling after fermentation. 0 refers to unrecognized, 2 refers to can be recognized, 4 refers to weak, 6 refers to middle, 8 refers to strong, 10 refers to very strong). chemical after aldehydes. Among the ketones, 2,2,6-trimethylcyclohexanone and \(\beta\)-ionone showed relatively high concentrations. Alkenes are the third most abundant chemical after ketones. Among the ketones, 3,5,5-trimethyl-2-hexene and 8-heptadecene exhibited the highest relative abundance in concentration. As for the alcohols, 1-ocen-3-ol had the highest concentrations. These findings are consistent with those of [PERSON] et al. [17]. \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{NO.} & \multirow{2}{*}{RT/min} & \multirow{2}{*}{**Compounds**} & \multirow{2}{*}{RI *} & \multirow{2}{*}{RI *} & \multirow{2}{*}{**Ion**} & \multirow{2}{*}{**Identification**} & \multirow{2}{*}{**Standard Curves**} & \multirow{2}{*}{\(R^{2}\)} & \multirow{2}{*}{**SJS**} & \multirow{2}{*}{**FSJS**} \\ \cline{6-9} \cline{8-11}  & & & & & & & & & & & \\ \hline \multicolumn{9}{c}{Alcohols} \\ \(1\) & 9.79 & 1-Octen-3-ol & 979 & 976 & 57 72 & MS, RI, Std & Y = 1.409088X \(-\) 0.071092 & 0.999 & 62.4 \(\pm\) 3.0 & - \\ \(2\) & 11.37 & 2-Octen-1-ol & 1067 & 1069 & 57 68 & MS, RI, Std & Y = 6.551167X \(-\) 1.708406 & 0.999 & 4.6 \(\pm\) 1.3 & - \\ \(3\) & 12.22 & 1-Octen-1 & 1198 & 1194 & 79 91 & MS, RI, Std & Y = 1.080764X \(-\) 7.655212 & 0.989 & 2.6 \(\pm\) 0.4 & - \\ \(4\) & 16.18 & Cis-Anethol & 1214 & 1213 & 117 147 148 & MS, RI, Std & Y = 1.325534X \(-\) 2.097888 & 0.998 & 0.5 \(\pm\) 0.3 & - \\ \(5\) & 16.31 & Trans-2-decten-1-ol & 1265 & 1273 & 57 67 & MS, RI, Std & Y = 3.258641X \(-\) 4.058222 & 0.994 & 32.1 \(\pm\) 3.4 & - \\ \(6\) & 19.03 & Phenymethyl alcohol & 1299 & 1277 & 57 71 & MS, RI, Std & Y = 1.50527X \(-\) 1.245303 & 0.999 & - & 3.8 \(\pm\) 1.1 \\ \(7\) & 25.08 & 1-Nonanol & 1568 & 1569 & 55 56 70 & MS, RI, Std & Y = 2.968628X \(-\) 1.702484 & 0.993 & 0.6 \(\pm\) 0.1 & - \\ \(8\) & 27.50 & Cedrol & 1601 & 1601 & 95 150 222 & MS, RI, Std & Y = 2.74344X \(-\) 1.758548 & 0.994 & - & 8.2 \(\pm\) 0.2 \\ \multicolumn{9}{c}{Aldehydes} \\ \(1\) & 5.81 & Hexanal & 801 & 800 & 56 27 & MS, RI, Std & Y = 1.853681X \(-\) 0.051104 & 0.995 & 24.5 \(\pm\) 0.5 & - \\ \(2\) & 10.55 & 1-Nonanol & 1103 & 1102 & 57 71 & MS, RI, Std & Y = 0.63436X \(-\) 0.225634 & 0.993 & 47.4 \(\pm\) 1.7\({}^{e}\) & 11.6 \(\pm\) 1.5 \({}^{a}\) \\ \(3\) & 10.68 & 2-Nonneal & 1157 & 1158 & 55 70 & MS, RI, Std & Y = 11.75698X \(-\) 0.063402 & 0.995 & 1.3 \(\pm\) 0.7 & - \\ \(4\) & 10.93 & 2-4 & 1168 & 1175 & 105 133 134 & MS, RI, Std & Y = 2.029053X \(-\) 3.532768 & 0.994 & 0.8 \(\pm\) 0.1 & - \\ \(5\) & 13.50 & Oct-2-Fnal & 1192 & 1196 & 41 81 110 & MS, RI, Std & Y = 1.023365X \(-\) 5.773530 & 0.999 & 2.8 \(\pm\) 0.6 \({}^{e}\) & 12.0 \(\pm\) 2.2 \({}^{a}  
The fermented _S. japonica_ seedling was found to contain 26 volatile compounds (Table 1), including 2 alcohols, 6 aldehydes, 2 ketones, 8 alkanes, 3 alkenes, 4 esters, and 1 other compound. Fermentation affects the concentration of volatile compounds. As shown in Figure 2, the quantities of alcohols, aldehydes, alkanes, esters, ketones, and others decrease. Among these, alcohols and alkenes showed a significant decrease.