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Table 3 Effect of physical and nutritional parameters on GABA production by Lb. fermentum in soymilk: carbon source, MSG concentration, temperature, pH, incubation period, inoculum size

From: Optimization and comparison of -aminobutyric acid (GABA) production by LAB in soymilk using RSM and ANN models

Carbon source
  Control Glucose Sucrose Maltose Lactose
GABA (g/L) 0.46 ± 0.03 4.74 ± 0.03 2.4 ± 0.02 1.37 ± 0.02 3.96 ± 0.03
Concentration of glucose (%)
  Control 0.5 1 1.5 2
GABA (g/L) 0.42 ± 0.02 3.97 ± 0.02 4.74 ± 0.03 2.43 ± 0.03 0.79 ± 0.04
Viable count (log cfu/ml) 1.2 ± 0.03 4.73 ± 0.05 6.26 ± 0.1 5.33 ± 0 3.8 ± 0
pH 4.9 ± 0.3 4.5 ± 0.6 4.5 ± 0.2 4.3 ± 0.5 4.4 ± 0.5
Concentration of MSG (monosodium glutamate (%))
  Control 1 2 3 4
GABA (g/L) 0.45 ± 0.02 4.46 ± 0.05 4.21 ± 0.01 4.01 ± 0.03 3.74 ± 0.03
Viable count (log cfu/ml) 1.1 ± 0.01 6.8 ± 0.4 6.2 ± 0.5 5.3 ± 0.4 4.8 ± 0.4
pH 4.7 ± 0.4 4.4 ± 0.5 4.4 ± 0 4.4 ± 0 4.4 ± 0
Temperature (°C)
  Control (37) 25 30 35 40
GABA (g/L) 4.2 ± 0.04 2.83 ± 0.2 3.31 ± 0.2 4.01 ± 0.03 3.86 ± 0.1
Viable count (log cfu/ml) 6.1 ± 0.3 4.0 ± 0.5 4.5 ± 0.2 5.5 ± 0.3 4.2 ± 0.1
pH 4.4 ± 0 4.4 ± 0.5 4.4 ± 0 4.4 ± 0 4.4 ± 0
pH
  Control 4 5 6 7
GABA (g/L) 0.38 ± 0.02 2.35 ± 0.02 2.58 ± 0.04 2.59 ± 0.03 1.46 ± 0.1
Viable count (log cfu/ml) 0.8 ± 0.02 2.1 ± 0 4.3 ± 0.2 1.4 ± 0.1 1.1 ± 0.1
pH 5.2 ± 0 3.1 ± 0 3.4 ± 0 3.4 ± 0 4.1 ± 0
Incubation period (no. of days)
  Control 1 2 3 4
GABA (g/L) 0.48 ± 0.02 4.02 ± 0.01 4.27 ± 0.02 1.18 ± 0.02 0.86 ± 0.02
Viable count (log cfu/ml) 1.0 ± 0.02 6.7 ± 0.05 6.9 ± 0.02 4.8 ± 0.04 3.74 ± 0.06
pH 4.9 ± 0 4.4 ± 0 4.4 ± 0.1 4.4 ± 0.05 4.2 ± 0
Inoculum size (%)
  Control 1 2 3 4
GABA (g/L) 0.43 ± 0.04 3.79 ± 0.01 3.71 ± 0.05 2.62 ± 0.05 2.12 ± 0.04
Viable count (log cfu/ml) 1.2 ± 0.02 5.8 ± 0.3 6.4 ± 0.4 TNC TNC
pH 5 ± 0 4.4 ± 0 4.4 ± 0 4.4 ± 0 4.4 ± 0
  1. TNC too numerous to count
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