## 3 Results
### GC-IMS Analysis  
GC-IMS analyzes the characteristic fingerprints of volatiles from different samples [18]. In the 2D spectra, the red vertical line with a migration time of 1.0 ms indicates the reactive ion peak (RIP) [19]. To compare different samples, CK spectra were selected as a reference in Figure 2a with the same concentration in white. Blue indicates a lower concentration, and red indicates a higher concentration. The number of peaks and signal intensities of the volatile organic compounds (VOCs) produced by different cooking methods of low-salt wet-marinated fermented golden poppano varied significantly. The fingerprints of the different treated samples were compared (Figure 2b). Each column represents a compound, and the color indicates the content of volatile compounds. The results showed that different cooking methods significantly affected the flavor of golden pomfret. Volatile compounds, including 2-hexanone, ethyl sulfide, and 2-methyl-2-pentenal, were found in all six samples and may be considered shared volatile flavor substances and the relative amounts of the substances in the red boxes are relatively similar. Figure 2b visually compares the differences in VOCs between samples. According to Figure 2b  
Figure 1: Electronic nose radar map of samples with different cooking methods (**A**), loading analysis of samples with different cooking methods (**B**), PCA two-dimensional map of samples with different cooking methods according to an electronic nose (**C**). CK: uncooked treated samples, A: boiled samples, B: steamed samples C: microwaved samples D: baked samples, E: air fried samples. and Table S1, a total of 72 volatiles were detected, including 17 alcohols, 10 aldehydes, 11 ketones, 11 esters, 6 acids, 4 ethers, 3 olefins, and 5 other volatiles. Peak volume normalization was used to further summarize and compare the VOC content in different samples. As shown in Table S1, the contents of aldehydes were 20.61% (A), 17.32% (E), 17.12% (D), 16.40% (CK), 11.42% (C), and 8.23% (B). Aldehydes, which are primarily generated by the oxidation and degradation of fatty acids, have a lower threshold than other compounds and have a greater impact on the overall flavor of fish samples even at low concentrations [20]. The highest levels found were of 3-methylbutyratealdehyde (apple). Group B had significantly lower levels than the other cooking groups, and the lowest (\(p<0.05\)) total aldehyde levels. High concentrations of aldehydes produce an unpleasant rancid odor [21]. The ketone content ranged from 16.25 to 27.11%, and the ketone compounds included acetoin (cream), 2-pentanone (fruit), and acetone (butter). The CK group had a significantly higher content than the other groups (\(p<0.05\)). Although the ketone concentration threshold is low, it contributes positively to the flavor of fish samples [22]. The content of alcohols was 17.05-20.45% and included 3-methyl-3-butten-1-ol, 1-pentanol, ethanethiol, 3-methyl-2-butanol, 2-propanethiol, and 2-hexanol. Alcohols are generally produced from fatty acids via the decomposition of hydroperoxides catalyzed by lipid oxidases or via the reduction of carbonyl compounds. The alcohol content was approximately 20%, with no significant differences between groups [7]. Esters impart a fruity taste to meat products and have an important influence on flavor [23]. The content of esters was  
Figure 2: Two-dimensional topographic plot (**a**) and fingerprint spectra (**b**) of the different cooking methods used for GC-IMS. CK: uncooked treated samples, A: boiled samples, B: steamed samples C: microwaved samples D: baked samples, E: air fried samples. 10.86-15.59% and included propyl acetate, ethyl acrylate, propyl propionate, and other esters. Group D had a significantly greater content of phenolic compounds than the other groups (\(p<0\)). Acids are primarily produced by the oxidation of fatty acid triglycerides or the microbial fermentation of amino acids [24].