2.3. Preparation of inoculum and fermentation
LAB was prepared in MRS broth by inoculating its colony. The cell number was approximately 9 Log CFU/mL after activation in MRS broth at 37 C for 18 h. Cells of LAB were harvested by centrifugation at 4500 rpm for 15 min and thenwashed twice with
0.9% saline. For all cultures, the initial cell counts in the fermentation
were about 3e4 Log CFU/mL.
The pickle jar was filled with water to exclude air, and then kept at ambient temperature (25e27 C). The culture system was monitored for seven days to ensure the growth of LAB, substrate metabolism and metabolite formation.