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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