## 3 Results
### Determination of Flavor Profiles and Herbal Compositions from Different Treatments  
* Volatile Gallery Plot and the Herbal Compositions of Samples with Enzymatic Hydrolysis  
HS-GC-IMS was used to acquire sample information with different processing methods. Selected regions in the gallery plot of Figure 2 represent highly concentrated components in either of the samples after enzymatic hydrolysis. Different treatments of decocting (#2), SF with residue (#3), and IF without residue (#4) generated different volatile compounds. It is proved that different fermentation modes have distinctive volatile profiles depending on the microorganisms involved [29]. Three sample groups of #2, #3, and #4 were well spread on the principal component analysis which accounted for 48% (PC2) and 51% (PC1) of the cumulative variances. Samples from SF with residue (#3) delivered a higher degree of deviation than the other two groups. Fifteen volatile compounds in group #2, twenty-seven volatile compounds in group #3, and twenty volatile compounds in group #4 appeared in the topographic plot. These compounds were further categorized in groups in Figure 3a. The relative content of volatile compounds in group #2 was mostly assigned to aldehydes (58.53% of the total) and ketones (22.30% of the total). Under the influence of microorganisms, aldehydes and ketones in the unfermented decoction (group #2) were reduced to form esters and alcohols in groups #3 and #4. There was a higher number of aldehydes in group #3 than in group #4. In addition to enzyme oxidation, in Strecker degradation (heat during decoction) and microbial metabolism, aldehydes come partially from amino acids [30]. This corresponded to the amino acid analysis, in which group #3 had lower concentrations of amino acids than group #4. Higher ketone concentrations were observed in groups #2 and #4, suggesting a higher degree of oxidation of fatty acids in both treatments due to heating and fermentation [31]. Compounds such as furan and pyrazine, which are the result of Maillard reactions and Strecker degradation in the heating process [32], were also found in this study. * Herbal compositions were identified by UHPLC-Q-TOF/MS. There were 115 compounds upregulated and 241 downregulated when comparing group #3 to group #2; 226 compounds were upregulated and 169 were downregulated when comparing group #4 to group #2. With different fermentation strategies in group #3 and group #4, 277 compounds were upregulated and 80 downregulated. These differential  
Figure 3: Comparative analysis of the relative contents (%) of volatile compounds in herbal broth subjected to enzymatic hydrolysis and fermentation. (**a**) Effect of enzymatic hydrolysis and fermentation; (**b**) Comparison of direct plant extraction and probiotic fermentation. Figure 2: HS-GC-IMS topographic plots (**top panel**) and gallery plot fingerprints (**bottom panel**) of volatile flavor compounds in samples from groups #2, #3, and #4. Top panel in left to right and bottom panel in top-down order. compounds were visualized in the volcano plots (\(p<0.05\), FC \(>1.2\) and VIP \(>1\), Figure 4). * Volatiles and Differential Compounds from Direct Plant Extraction and Probiotic Fermentation Distinctive differences in volatile compounds were found in groups #1 and #4, indicating that the different treatments profoundly altered the spectrum of volatile components (Figure 5). Fifteen volatile compounds, mostly aldehydes, increased noticeably in group #1. Forty-one volatile compounds in group #4 increased significantly. As shown in Figure 3b, the relative content of volatile compounds in group #1 was mostly attributed to aldehydes (45.24% of the total) and ketones (39.35% of the total). This profile was shifted to relatively high proportions of aldehydes (32.34%), alcohols (19.29%), ketones (17.42%), and esters (22.93%) in group #4 after sequential probiotic fermentation. _Lactobacillus_ species were reported to catalyze the esterification of short-chain fatty acids with diverse alcohols [26].