Table 4. Production of diacetyl with the addition of different concentrations of citrate

Citrate (%, w/v)	Diacetyl (mg/L)
0	19.85±0.38
0.1	40.48±0.32^b
0.2	43.26±0.44^b
0.3	42.75±1.41^b
0.5	43.01±0.59^b
1.0	42.85±1.43^b
2.0	34.43±1.64^a
3.0	35.20±1.05^a

Results are expressed as mean±SE (n=3).
MRS broth was used as the basal medium, citrate was added before sterilization (autoclave, 121°C, 15 min). The initial concentration of diacetyl was 0.
Means in the same column with different lowercase superscript letters are significantly different at p<0.05.