Production of high γ-aminobutyric acid (GABA) sour kimchi using lactic acid bacteria isolated from Mukeunjee kimchi

A sour kimchi product with an elevated amount of γ-aminobutyric acid (GABA) was produced using starter lactic acid bacteria (LAB) for mukeunjee kimchi fermentation. The starter LAB were screened and isolated from the commercial mukeunjee kimchi product that showed the highest GABA content and was identified as Lactobacillus buchneri. The maximum GABA production of L. buchneri in MRS media was 5.83 mg/mL at pH 4.2 and the addition of 3% NaCl did not significantly (p>0.05) changed GABA production of L. buchneri. The amount of GABA in L. buchneri-inoculated sour kimchi was 61.65 mg/100 g, which represented about 8 times higher than the L. buchneri uninoculated kimchi (control kimchi). A sensory evaluation test of L. buchneri-inoculated sour kimchi and control kimchi showed that the L. buchneri inoculation may produce more sour kimchi than control kimchi, but there was no difference in the general acceptance between the 2 kimchi products (p>0.05).