## 3 Results
### Effect of Fortified Inoculation with L. brevis Lbr17 on the Fermentation Process
brevis_ in the fortified fermentation group (T group) decreased compared to the control group (CK group), which can be attributed to a decrease in the overall number of _L. populations_. This finding holds significant value in guiding targeted adjustments to unexpected microorganisms during the fermentation process through the use of mutually exclusive microorganisms. Furthermore, it reveals how fortified inoculation enhances the controllability of the fermentation process. Yeast: The overall trend of yeast during fermentation is consistent with the total fungal trend. Interestingly, the number of yeasts reached its lowest value at 21 d, indicating a consistent response of total fungi and yeast to the fermentation environment changes following the fortified inoculation of _L. brevis_ (Lbr17). This finding serves as a reference for determining the inoculation time of fortified fermentation with _L. brevis_ (Lbr17). _L. brevis_: During the fermentation process, _L. brevis_ exhibited dynamic changes. The direct impact of fortifying the inoculation of _L. brevis_ was observed only within the first 15 d, with the fortified fermentation group (T group) showing a higher number of _L. brevis_ compared to the control group (CK group). Afterwards, the copy number of _L. brevis_ in both groups tended to stabilize. From days 25 to 28, there was a slight decrease in the number of _L. brevis_, whereas the number of other bacteria in the _Lactobacillus_ genus remained stable. However, the total bacterial count increased during this period. This could be attributed to _L. brevis_ promoting the growth of bacteria not belonging to the _Lactobacillus_, whereas its own growth displayed a declining trend, possibly due to limitations in spatial niche availability. The fermentation trials showed similar initial pH and titrate acid values (Figure 5A). Both pH and titratable acid exhibited more significant changes within the first 7 days, followed by a relatively stable trend. On the first day, there was a sharp change in pH, decreasing from 6.2 to 4.1, and an increase in titratable acid from 0.06 to 0.12 mmol NaOH/g. The T group showed a lower pH value and higher titrate acid value as compared to the CK group after the first day of fermentation. The moisture content and reducing sugar levels during the 28-day fermentation process are depicted in Figure 5B. The overall trend for reducing sugar and moisture content was consistent. Both reducing sugar and moisture content decreased on the first day, followed by a slight increase on the third day, and then rapidly declined. After inoculation on the 15 th day, they tended to stabilize. When comparing the fortified fermentation group (T group) to the CK group, the moisture content and reducing sugar levels of the fortified fermentation group remained at a higher level, indicating a more stable fermentation process. The volatile compounds present at 21 d and 28 d during fermentation were analyzed using HS-SPME-GC-MS (Figure 6). When comparing the main volatile flavors of the fortified fermentation group (T group) (Lbr17) at 21 days and the control group (CK group) at 28 days, it was found that the content of main flavor compounds, such as isoamyl acetate and 1-hexanol increased significantly without significant decrease in the ethanol concentration at 21 d in the T group (Lbr17). Additionally, some important volatile flavor compounds, including ethyl acetate, 2-methoxy-phenol, diethyl suberate, 2,4-di-tert-butylphenol, benzyl alcohol, and ethyl octanate, showed slight increases. Figure 5: Dynamics of physiochemical properties during the fermentation process. (**A**) The X-axis represents fermentation time, the left Y-axis represents pH value, the right Y-axis represents titralbe acidity; (**B**) The X-axis represents fermentation time, the left Y-axis represents moisture the right Y-axis represents reducing sugar. Values represent the means of three replicates with their standard error bars.