## 3 Results
### GC-MS Analysis
The higher contents of methyl 2-hydroxy-4-methylpentanoate and diisobutyl 2,2,4-trimethyl-1,3-pentanediol diisobutyrate confer a fruity aroma after cooking [32]. Small amounts of certain acids, such as caprylic acid, nonanoic acid, myristic acid, and n-pentadecanoic acid, have a fruity, coconutity, and waxy flavor, respectively, and were also detected [23]. The content of volatile flavor substances did not effectively indicate a key role in the overall flavor of the samples. Therefore, the samples were analyzed in the context of their own flavor thresholds. There were 15 key flavor substances with 0 \(<\) OAV \(<\) 1 in the different treatment groups (Table 2) and 11 key flavor substances with OAV \(\geq\) 1, including hexanal, isovaleraldehyde, nonanal, (E)-2-duodenal, (E)-2-nonrenal, 2-octenal, decanal, acetoin, 2-nonanone, 1-octen-3-ol, and D-limonene. Nonanal, (E)-2-nonrenal, 1-octen-3-ol, D-limonene, and Estragole were the key compounds shared by the B, A, D, C, and E groups and contributed significantly to the formation of the flavor of cooked golden pomfret. Together, these compounds formed the flavor profile of golden pomfret, which was dominated by the aroma of oil and fat, with the aroma of green grass and a fruity flavor arising after cooking. The contents of the key flavor compounds in the six treatment groups were significantly different. Nonanal and 1-octen-3-ol were most prominent in the B and A groups and gave the low-salt wet-marinated golden pomfret a bland greasy flavor after high-temperature steaming. The key flavor compounds of hexanal, nonanal, and 1-octen-3-ol in the D and E groups had a significant effect on the overall flavor and gave the low-salt wet-marinated golden pomfret a mushroom and fruity aroma after high-temperature roasting and deep-frying. Hexanal, nonanal, and 1-octen-3-ol were also found in the C group. The OAVs of nonanal, acetoin, and 1-octen-3-ol were higher in group CK, and the golden pomfret after microwave cooking showed a mixed aroma of fat and fruit. The OAVs of nonanal, 2-octenal, acetoin, and 2-nonanone were lower in group CK, which indicated that the flavor was more muted than the other groups. In conclusion, the differences in the contents of key volatile flavor substances were an important reason for the differences in odor composition. A key cause of these differences was that the flavor profile of golden pomfret is richer after cooking. The interactions between the key flavor compounds also contributed significantly to the overall flavor of the samples. Overall, different cooking methods had significant effects on the formation of certain volatile flavor compounds in the fish. Steaming treatments produced higher aldehyde contents and more unpleasant odors. Baking and air-frying treatments promoted the formation of more aggressive odors in the fish, which was likely due to the combination of high temperatures, protein denaturation, lipid oxidation, and the Maillard reaction. OPLS-DA of Odor-Active Compounds from Different Cooking Methods  
OPLS-DA is an analytical method for visualizing data and quantifying the degree of variation between samples using correlations between data [34]. The relative concentrations of substances with OAV > 1 in Tables 2 and S3 were selected as the Y variables for the OPLS-DA modeling design. The explanatory power of the model for the X and Y matrices was expressed as R\({}^{2}\)X and R\({}^{2}\)Y, respectively, and the predictive power of the model was expressed as Q\({}^{2}\), with an R\({}^{2}\) and Q\({}^{2}\) closer to 1.0 indicating a better fit for the model. Figure 4A shows that R\({}^{2}\)Y = 0.997 and Q\({}^{2}\) = 0.994, which indicates that the model had good explanatory and predictive ability [35; 36]. As shown in the figure, samples treated with different cooking methods were well separated. Y was located in the first quadrant, E was located in the second quadrant, D and A were located in the third quadrant, and C was located in the fourth quadrant. B was distributed in the second and third quadrants.