• The Korean Journal of Food And Nutrition
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• v.31 no.3
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• pp.408-415
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• 2018

This study aimed to investigate the changes in the ${\gamma}$-aminobutyric acid (GABA) content of bitter melon (Momordica charantia L.) cultivated from different regions, with different harvest times and at various maturation stages. Methods for observing the changes in GABA content were validated by determining the specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), and precision and accuracy using the HPLC-FLD system. Results showed high linearity in the calibration curve with a coefficient of correlation ($R^2$) of 0.9999. The LOD and LOQ values for GABA were 0.29 and $0.87{\mu}g/mL$, respectively. The relative standard deviations for intra- and inter-day precision of GABA were less than 5%. The recovery rate of GABA was in the range of 98.77% to 100.50%. The average content of GABA was 0.93 mg/g and Cheongju showed highest GABA content of 1.88 mg/g. As the time of harvest increased from May to September, the GABA content decreased from 1.56 to 0.86 mg/g. Also, maturation of the bitter melon fruit was associated with a decreased in GABA content.

• Journal of Life Science
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• v.17 no.7 s.87
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• pp.970-975
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• 2007

For the screening of ${\gamma}-aminobutyric$ acid (CABA)-producing bacteria, 86 bacterial strains which produce GABA were isolated from Kimchi and Salted fisk .Among these, three strains designated AML15, AML45-1, AML72 with relatively high GABA productivity were selecled by thin layer chromatography (TLC). To elucidate the relationship between isolated strains and the genus Lactobacillus, their 16S rDNA sequence were examined. The result of their DNA sequences showed 99% similarity with Lactobacillus brevis ATCC 367. On the basis of the these results, isolated strains were identified as Lactobacillus brevis and designated L. brevis AML15. In order to determine the optimum conditions for GABA production, the isolated strains were cultivated in pyridoxal phosphate (PLP) and monosodium glutami. acid (MSG). Results showed that L. brevis AML15 had the highest CABA productivity with 10,424 $nM/{\mu}l$ concentration in MRS broth containing 5% (w/v) MSG and 10 ${\mu}M$ PLP at pH 5.0. The results imply that L. brevis AML15 has the potential to be developed as a strain for GABA hyper-production.

• Journal of Microbiology and Biotechnology
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• v.29 no.2
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• pp.209-221
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• 2019

Gamma-aminobutyric acid (GABA) is a neurotransmitter that exerts several physiological functions and positive effects on human health. The aim of this study was to isolate and characterize the strains that had GABA-producing abilities from various fermented fish products. A total of 91 acid-producing strains were isolated from 41 samples of fermented fish products, and 27 strains showing GABA-producing abilities were identified by the 16S rDNA sequences. Among the strains, 31% strains tolerated at high-salt environment of 10-20% throughout the fermentation of fish sauces. The 27 isolates that produced GABA at various concentrations did so in the range of 5 to 454 mM. These GABA-producing isolates were identified as lactic acid bacteria of 14 strains, which included twelve Lactococcus lactis, one Enterococcus faecium, and one Lactococcus pentosus; eight Bacillus cereus group, which included seven B. thuringiensis and one B. cereus; and five Staphylococcus spp. Interestingly, with Vietnamese fish sauces, we mostly identified species of B. thuringiensis and Staphylococcus spp., while with Korean fermented fish products, the majority of the strains identified belonged to L. lactis. Among the strains, B. thuringiensis LH2134 produced the highest levels of GABA at 366 mM among the strains identified from Vietnamese fish sauces, whereas L. lactis LA43, a new strain isolated from Korean jeotgal (salted shrimp paste), produced the highest amount of GABA at 454 mM and the glutamate concentration in the medium was essential for GABA accumulation. Therefore, such the isolates might serve as good starters for development of more GABA-reinforced foods among fermented fish products.

• Journal of Microbiology and Biotechnology
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• v.24 no.11
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• pp.1592-1596
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• 2014

To evaluate the effect of Lactobacillus brevis G-101 on absorption of monosodium glutamate (MSG), we orally administered MSG with or without G-101 in mice and measured the maximum concentration (Cmax) and blood concentration curve (AUC) of MSG and ${\gamma}$-aminobutyric acid (GABA). Oral administration of G-101 ($1{\times}10^9CFU/mouse$) potently inhibited Cmax and AUC of MSG by 97.8% and 94.3%, respectively (p < 0.05), but increased those of GABA by 32.1% and 67.7%, respectively (p < 0.05). G-101 inhibited the absorption of MSG. These results suggest that G-101 may reduce the side effect of MSG by inhibiting the absorption of MSG.

• Journal of Life Science
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• v.18 no.12
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• pp.1723-1727
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• 2008

Chlorella sp. CMS-1 strain was isolated from the outdoors cultivation pools in Culmansa Co., Ltd. This strain was found to be a rounded type of 3 ${\mu}m$. Phylogenetic analysis by the 18S rRNA sequencing using isolated strain is most similar to Chlorella sp. IFRPD 1018 gene at the level of nucleotide sequence identity at 99%. Accordingly, the isolated Chlorella strain was named as Chlorella sp. CMS-1 based on its morphological and phylogenetic properties. The concentrations of crude protein and fat were 59% and 0.01%, respectively. Major compositional amino acids (mg%) were glutamic acid 6.21, alanine 5.76, aspartic acid 5.44%, glycine 4.29%, and threonine 3.09% and major free amino acids (mg%) were ${\gamma}$-aminobutyric acid (GABA) 7.13%, L-alanine 1.44%, L-glutamic acid 0.90, L-leucine 0.26% and L-glycine 0.20%. The concentrations of major minerals were P 2.25%, K 2.25%, Na 1.09%, Mg 0.63%, and Ca 0.28%.

• Food Science of Animal Resources
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• v.37 no.6
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• pp.804-812
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• 2017

This study was carried out to determine the physicochemical, microbiological, and quality characteristics of a new type of fermented sausage manufactured by incorporating Baechu-kimchi powder and gamma-aminobutyric acid (GABA)-producing lactic acid bacteria (LAB). The LAB count was at the maximum level by day nine of ripening in inoculated sausages, accompanied by a rapid decrease in the pH. The addition of kimchi powder decreased the lightness ($L^*$) and increased the redness ($a^*$) and, yellowness ($b^*$) values, while also significantly increasing the hardness and chewiness of the sausage (p<0.05). Moreover, although the thiobarbituric acid reactive substances values increased in all samples during the study period, this increase was lower in the kimchi-treated samples, indicating a reduction in lipid oxidation. Overall, our results show that the addition of Baechu-kimchi powder to sausages reduced the off-flavor properties and improved the taste profile of the fermented sausage in sensory evaluations. The GABA content of all fermented sausages increased from 17.42-25.14 mg/kg on the third day of fermentation to 60.95-61.47 mg/kg on the thirtieth day. These results demonstrate that Baechu-kimchi powder and GABA-producing LAB could be functional materials in fermented sausage to improve quality characteristics.

• Journal of Life Science
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• v.27 no.5
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• pp.567-574
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• 2017

This study is to isolate and identify ${\gamma}$-amino butyric acid (GABA) producing lactic acid bacteria (LAB) from Makgeolii, traditional Korean rice wine and then establish the optimal culture conditions for GABA production. Sixty four LAB from Makgeolli were isolated according to the characteristics of the shape and color of the colony grown on MRS agar plate. The GABA production of the isolated strain cultured in MRS broth contained 1% MSG (mono-sodium glutamate) were determined and evaluated by TLC and HPLC analysis. Strain B-134 was selected for highest GABA production. From the analysis of 16S rRNA and glutamate decarboxylase B (gadB) gene sequences, strain B-134 was tentatively identified as a Lactobacillus plantarum subsp. plantarum B-134. Effects of culture parameters, including glutamic acid level, culture temperature, NaCl level, and pH on GABA production were investigated for culture optimization. The optimum culture condition for GABA production by B-134 were culture temperature of $37^{\circ}C$, pH of 5.7, NaCl content of 0% (w/v) and MSG content of 3% (w/v), which produced 25 mM of GABA during cultivation time of 48 hr. From these results, strain B-134 is expected to be utilized as useful microorganisms for GABA-enriched health beneficial food.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2002.10a
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• pp.9-11
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• 2002

• International Journal of Oral Biology
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• v.30 no.3
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• pp.91-98
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• 2005

Gamma-aminobutyric acid (GABA) is known as an inhibitory neurotransmitter in the neurons of the central nervous system. However, its detailed action mechanisms in the rostral gustatory zone of the nucleus tractus solitarius (rNTS) have not been established. The present study was aimed to investigate the distribution, role and action mechanisms of GABA in rNTS. Membrane potentials were recorded by whole cell recordings in isolated brain slices of the rat medulla. Superfusion of GABA resulted in a concentration-dependent reduction in input resistance in the neurons in rNTS. The change in input resistance ws accompanied by response to a depolarizing pulse were diminished by GABA. Superfusion of the slices with either $GABA_A$ agonist, muscimol, $GABA_B$ agonist, baclofen or $GABA_C$ agonist, TACA, decreased input resistance and reduced the nerve activity in association with membrane hyperpolarization. It is suggested that inhibitory signals playa role in sensory processing by the rNTS, in that GABA actions occur through activation of $GABA_A,\;GABA_B\;and\;GABA_C$ receptor. These results suggest that GABA has an inhibitory effect on the rNTS through an activation of $GABA_A,\;GABA_B\;and\;GABA_C$ receptors and that the GABAergic inhibition probably plays an important role in sensory processing by the rNTS.

• Journal of Microbiology and Biotechnology
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• v.29 no.6
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• pp.933-943
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• 2019

Gamma-aminobutyric acid (GABA)-producing strains were isolated from four edible insects and subjected to 16S rRNA sequence analysis. Among the four GABA-producing bacteria, Enterococcus avium JS-N6B4 exhibited the highest GABA-production, while cultivation temperature, initial pH, aerobic condition, and mono-sodium glutamate (MSG) feeding were found to be the key factors affecting GABA production rate. The culture condition was optimized in terms of glucose, yeast extract, and MSG concentrations using response surface methodology (RSM). GABA production up to 16.64 g/l was obtained under the conditions of 7 g/l glucose, 45 g/l yeast extract, and 62 g/l MSG through the optimization of medium composition by RSM. Experimental GABA production was 13.68 g/l, which was close to the predicted value (16.64 g/l) calculated from the analysis of variance, and 2.79-fold higher than the production achieved with basic medium. Therefore, GABA-producing strains may help improve the GABA production in edible insects, and provide a new approach to the use of edible insects as effective food biomaterials.