# The Impact of Different Cooking Methods on the Flavor Profile of Fermented Chinese Spicy Cabbage
## 2 Results and Discussion
### Variation in VFC Profile
\begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline
**Number** & **Compounds** & **LR1\({}^{\ast}\)** & **LR1\({}^{\ast}\)** & **LR1\({}^{\ast}\)** & **Concentration** & **OAV** & **Concentration** & **OAV** & **Concentration** & **OAV** & **Concentration** & **OAV** & **Overception** \\  & & & & (log/kg) & (deg/kg, CK-CSO) & (cK-CSO) & (ug/kg, BL-CSO) & (BL-CSO) & (ug/kg, SF-CSO) & **S/SF-CSO** & **S/SF-CSO** & \\ \hline \hline \multicolumn{2}{c}{**Tropens (B)**} & & & & & & & & & & \\ \hline
41 & \(\beta\)-Sesquipieblaudeme & 1773 & \(1772\pm 8\) & 36 [34] & \(112.02\pm 3.592\) \({}^{\ast}\) & 3.11 & 48.98 \(\pm 5.53\) \({}^{\rm h}\) & 1.36 & n.d. & Fruity, herbal [34] \\
42 & Zingbememe & 1723 & \(1724\pm 9\) & & \(170.58\pm 48.77\) \({}^{\ast}\) & 63.60 \(\pm 12.44\) \({}^{\rm h}\) & 17.68 \(\pm 4.48\) \({}^{\rm h}\) & & Slee, fresh [35] \\
43 & \(\beta\)-Busolome & 1729 & \(1727\pm 11\) & & 80.63 \(\pm\) 20.22 \({}^{\ast}\) & 33.43 \(\pm 3.09\) \({}^{\rm h}\) & n.d. & Shanker, woods [34] \\
44 & Farnese & 1744 & \(1746\pm 9\) & n.d. & 12.34 \(\pm\) 0.23 \({}^{\ast}\) & n.d. & Livershield, & Livershield, \\
45 & Concumune & 1778 & \(1777\pm 9\) & & 284.92 \(\pm\) 111.48 \({}^{\ast}\) & 111.25 \(\pm\) 15.00 \({}^{\rm h}\) & 13.00 \(\pm\) 242 \({}^{\rm h}\) & & Herphal [34] \\ \hline \multicolumn{2}{c}{**Nucleiles (I)**} & & & & & & & & \\ \hline
46 & Benzenpropennitrile & 23027 & 2041 \(\pm\) 7 & 1317.01 \(\pm\) 207.72 \({}^{\ast}\) & 763.87 \(\pm\) 3.390 \({}^{\rm h}\) & 1703.69 \(\pm\) 321.51 \({}^{\ast}\) & Aldehyde, spicy [37] \\ \hline \multicolumn{2}{c}{**Phenoms (I)**} & & & & & & & & \\ \hline
47 & 2.4-Dk-start-bybythend & 2316 & 2318 \(\pm\) 10 & n.d. & 30.62 \(\pm\) 10.89 \({}^{\ast}\) & n.d. & \\ \hline \hline \end{tabular} \({}^{\rm(I)}\) The concentrations are the means of three repetitions \(\ast\) standard deviation. (2) Different letters for the same row indicate significant differences according to [PERSON]’s multiple range, text (\(p<0.05\)), (2) IR \(\uparrow\) linear western index calculated by a bandpasses series of n-alanine (C-C-A). (6) LR1\({}^{\ast}\) linear western index index of reference compounds in NIST library and literature. (5) In \(\alpha\).d. Not detected, (8) OAV were calculated by dividing the average concentration by the dot threshold. (7) Aroma-active compounds identified by OAV and GC-AS in CSC sample. (8) Abbreviations: CSC, Chinese spiky catalogue, CK-CS, the CSC without thermal processing group; BC-CS, bolied CSC; SF-CS, sit-fixed CSC; OAV, color activity value.  
\end{table} 
Table 1: _Cont._Figure 1: Variation in VFC profile of CSC after cooking. **(a)** VFC Venn diagram. **(b)** VFC concentration of different CSC samples. Abbreviations: VFCs, volatile flavor compounds; CSC, Chinese spicy cabbage; CK-CSC, the CSC without thermal processing group; BL-CSC, boiled CSC; SF-CSC, stir-fried CSC. To further investigate the discriminatory VFCs contributing to the CSC after cooking, the PCA was applied. As shown in Figure 2a, PC 1 and PC 2 accounted for 83.6% of the total variation. The VFCs of CK-CSC, SF-CSC, and BL-CSC were diverse and distinct, and they were mainly located in the first, second, and third quadrant, respectively. The PCA confirmed that different cooking methods affected the composition of flavor compounds of CSC. A heatmap was applied to exhibit how the different cooking methods varied in flavor compound composition by applying Euclidean distance as a similarity measure (Figure 2b). The clustering in the dendrogram was similar to the PCA plots (Figure 2a) and the groupings were consistent with the PCA results. The VFCs of CSC after cooking were distinguished. Figure 2: _Cont._  
Figure 2: Evolution of flavor compounds in CSC samples under different cooking methods. **(a)** Biplot of the flavor compounds identified from CSC. The number was in accordance with that in Table 1. **(b)** Heatmap analysis of flavor compounds of CSC samples.