• The Korean Journal of Physiology and Pharmacology
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• v.14 no.3
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• pp.127-132
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• 2010

Reactive oxygen species (ROS), which include hydrogen peroxide ($H_2O_2$), the superoxide anion (${O_2}^-{\cdot}$), and the hydroxyl radical ($OH{\cdot}$), are generated as by-products of oxidative metabolism in cells. The cerebral cortex has been found to be particularly vulnerable to production of ROS associated with conditions such as ischemia-reperfusion, Parkinson's disease, and aging. To investigate the effect of ROS on inhibitory GABAergic synaptic transmission, we examined the electrophysiological mechanisms of the modulatory effect of $H_2O_2$ on GABAergic miniature inhibitory postsynaptic current (mIPSCs) in mechanically isolated rat cerebral cortical neurons retaining intact synaptic boutons. The membrane potential was voltage-clamped at -60 mV and mIPSCs were recorded and analyzed. Superfusion of 1-mM $H_2O_2$ gradually potentiated mIPSCs. This potentiating effect of $H_2O_2$ was blocked by the pretreatment with either 10,000-unit/mL catalase or $300-{\mu}M$ N-acetyl-cysteine. The potentiating effect of $H_2O_2$ was occluded by an adenylate cyclase activator, forskolin, and was blocked by a protein kinase A inhibitor, N -(2-[p-bromocinnamylamino] ethyl)-5-isoquinolinesulfonamide hydrochloride. This study indicates that oxidative stress may potentiate presynaptic GABA release through the mechanism of cAMP-dependent protein kinase A (PKA)-dependent pathways, which may result in the inhibition of the cerebral cortex neuronal activity.

• Journal of Mushroom
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• v.17 no.4
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• pp.268-274
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• 2019

Sparassis latifolia is a useful medicinal mushroom that has recently gained popularity in Asia. It has a rich flavor and is a good source of nutrients contains a large number of polyphenols for a functional food or dietary supplement. In addition, S. latifolia is rich in beta-glucan and gamma-aminobutyric acid (GABA). These two compounds have been reported to show immune-stimulating and anticancer effects by numerous studies. In this study, four species of lactic acid bacteria (Lactobacillus plantarum subsp. plantarum, L. acidophilus, L. helveticus, and L. delbrueckii subsp. bulgaricus) were used to ferment the fruiting body of S. latifolia. Fermented S. latifolia extracts were found to have a higher polyphenol content and antioxidant activity following fermentation as well as increased protease activity.

• The Korean Journal of Food And Nutrition
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• v.27 no.4
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• pp.692-698
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• 2014

In this study, we investigated cancer cell growth inhibitory effects of kimchi extracts obtained from cabbage kimchi. Kimchi extracts (S46h, S47h, S48h) were obtained from the samples fermented at $15^{\circ}C$ for 46 h, 47 h, and 48 h during the first 10 days, which were subsequently stored at $-1.4^{\circ}C$ in kimchi refrigerator (hereinafter DV kimchi extracts). The samples showed a higher anti-proliferative effect against AGS (human, gastric adenocarcinoma) cell lines compared to control kimchi extract (S0h) obtained from sample stored at $-1.4^{\circ}C$ without fermentation. The DV kimchi contained higher levels of ${\gamma}$-aminobutyric acid (GABA) and ornithine compared to the control kimchi extract. Among the DV kimchi extracts, the S46h sample showed a higher anti-proliferative effect against the cancer cell growth and contained higher amount of GABA than the other kimchi samples. These results suggest that the consumption of DV kimchi can be more beneficial, as it is rich in GABA and ornithine. Therefore, it could be helpful in retarding the proliferation of cancer cells compared to the control kimchi.

• Applied Biological Chemistry
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• v.47 no.2
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• pp.216-221
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• 2004

Changes in physiological functionality of giant embryonic rice by germination process were investigated using 70% ethanolic extract of the rices. Physiological functionality was evaluated by determining the reducing power, phenolic compound content, GABA content, and antimutagenicity. The results showed that the order of reducing power of the non-germinated rices was Nampung giant embryonic rice>normal rice> Whachung giant embryonic rice, however, the activity was high as the order of Whachung giant embryonic rice> Nampung giant embryonic rice> normal rice by germination process. About 3-fold activity increase was observed for Whachung giant embryonic rice, while, the activity of Nampung giant embryonic rice and normal rice decreased by the same treatment. The phenolic compound content of three rice cultivars were found to be almost same levels. Germination of rice increased the content of phenolic compounds by 2.6-fo1d without any considerable changes for both Nampung giant embryonic rice and normal rice. The GABA contents was highest in Whachung giant embryonic rice, followed by Nampung giant embryonic rice, normal rice in either germination or non-germination condition. The germination increased the GABA contents by more than 2.4-fold for all rice cultivars tested. We also found an increase in the antimutagenic activity by germination process for all cultivars, where the activity was the greatest for Whachung cultivar.

• Journal of Life Science
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• v.17 no.8 s.88
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• pp.1141-1146
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• 2007

This study investigated the effects on the biological activities of germinated brown rice soaked in mycelial culture broth of Phellinus linteus. The level of free amino acid was higher in the GBRP extract than those of BR and GBR. The major free amino acids were alanine, valine, isoleucine and methionine in both extracts. The level of ${\gamma}$-aminobutyric acid (GABA) was also increased significantly in the GBR and GBRP. Antioxidant activities of methanol extract of BR, GBR and GBRP were measured by using DPPH radical scavenging and SOD-like activity. Antioxidant activities showed the highest level of 83% and 76% when 100 mg/ml GBR and GBRP, respectively. Stimulation of the macrophages RAW264.7 cells with lipopolysaccharide (LPS) resulted in increased production of nitric oxide (NO) in the medium. However, the methanol extract of GBR and GBRP showed marked inhibition of NO synthesis in a does-dependant manner. These results showed that GBR and GBRP were significant role for activation of immune system in the pathogenesis of inflammatory diseases.

• Food Science and Preservation
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• v.18 no.6
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• pp.859-868
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• 2011

This study was conducted to determine the appropriate mixing ratio of Koji and rice Doenjang. Brown rice Doenjang (BR) was prepared with three different ratios of cooked soybean to brown rice Koji [1.5:1 (BR-1); 2:1 (BR-2); and 3:1 (BR-3)], and polished-rice Doenjang (PR) was prepared with cooked soybean and polished-rice Koji (2:1). The components related to the quality of Doenjang were analyzed during 60-day aging. No significant differences were found in the moisture and salt contents between the brown rice Doenjang and the polished-rice Doenjang. The pH, titratable acidity, and bacteria cells increased at 20-30 days aging time, and decreased thereafter. The reducing-sugar and ethyl alcohol contents, on the other hand, increased at 10-20 days previously. These analytical values of the physicochemical and microbiological characteristics increased with the increase in the percentage of koji in each Doenjang. The amino-nitrogen and free-amino-acid contents showed the highest levels in BR-1: 887.6 and $4047.0{\pm}1.5$ mg%, respectively. The ${\gamma}$-aminobutyric-acid (GABA) contents slightly increased with increasing aging time. In the color of Doenjang, the lightness and yellowness increased along with the aging time, but the redness decreased as the aging time increased. These results showed that BR-1 processed the fermentation the fastest compared with the others. Moreover, the reducing-sugar, ethanol, and free-amino-acid contents as palatable components increased rapidly until 30 days aging time.

• Food Science and Preservation
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• v.24 no.8
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• pp.1138-1148
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• 2017

In this study, contetnts of phenolic acid and isoflavone, and biological activities of soy sauce were compared the soy sauce added bitter melon powder (BMPs). After the fermentation, pHs were decreased from 5.83 (0% BMP), 5.47 (5% BMP), and 5.32 (10% BMP) to 5.28, 5.36, and 5.16 at 90 days, whereas the acidities of soy sauce were increased from 0.06%, 0.07%, and 0.09% to 0.30%, 0.28%, and 0.36% at 90 days, respectively. In addition, the salinities of soy sauce were decreased, while viable cell numbers including Bacillus and yeast were increased. The contents of total phenolic, isoflavone-aglycone, and phenolic acid and antioxidant and ${\alpha}$-glucosidase inhibition activities were significantly increased for 90 days, while the isoflavone-glycoside contents were decreased. In Particular, soy sauce with 10% BMP at 90 days showed the highest contents of glutamic acid (GA, 9,876.09 mg/100 mL) and ${\gamma}$-aminobutyric acid (GABA, 325.02 mg/100 mL) contents than among other samples. Additionally, the radical scavenging activities (DPPH, ABTS, ${\cdot}OH$, and FRAP) and ${\alpha}$-glucosidase inhibition activities of soy sauce with 10% BMP at 90 days were shown to be high 96.07%, 97.27%, 59.47%, 1.98%, and 79.96%, respectively.

• Food Science of Animal Resources
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• v.29 no.4
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• pp.437-444
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• 2009

${\gamma}-Aminobutyric$ acid (GABA) producing lactic acid bacteria, Lactobacillus acidophilus RMK567 was cultivated in 50 L of sterilized MRS broth using a fermenter at $40^{\circ}C$ for 24 h. The cell number was increased to $10.04{\pm}0.13$ Log CFU/mL with a growth rate constant (k) of 0.454 generation/h and a generation time (g) of 2.303 h after a lapse of a lag phase (L) of 5.16 h. A total of 487 g of cell paste with 40.5% moisture was harvested with viable cell number of 12.48 Log CFU/g cell paste. The cell pastes after preparation with glycerol, glucose, and polydextrose as cryo-protectants were lyophilized under a vacuum of 84 m torr. A total of 408 g of freeze dried (FD) cell powders were mixed with a commercial strain of Streptococcus thermophilus to prepare of three types FD starter cultures with the viable cell numbers of 12.42 (FDA-GY), 12.60 (FDBGG) and 12.91 (FDC-GP) Log CFU/g. During preservation the FD cultures at -$18^{\circ}C$, the cell viability of the FD starter cultures were rapidly dropped to below 3.24% of the day of storage. No significant difference was found in the cell viabilities among three types of FD starters cultures, but significant difference (p<0.01) was found in storage periods. Yoghurts fermented through FD starter culture of L. acidophilus RMK567 were determined to contain $155.16{\pm}8.53$ ppm, $243.82{\pm}4.27$ ppm, and $198.64{\pm}23.46$ ppm of GABA, respectively. This study shows that GABA production activity of L. acidophilus RMK567 is not affected during the freeze drying process and would be available for commercial production of yoghurt containing high GABA content.

• Microbiology and Biotechnology Letters
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• v.48 no.1
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• pp.1-11
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• 2020

The aim of this study was to investigate the effects of Torulaspora delbrueckii and Saccharomyces cerevisiae, as pure fermenters and mixed fermenters (simultaneous and sequential culture), on the production of non-volatiles and volatiles, and on the antioxidant activity in Golden Dried Longan juice and Golden Dried Longan wines. Alanine, arginine, glutamic acid, leucine, proline, and gamma-aminobutyric acid (GABA) were the most prominent amino acids that were found in these wines. The Golden Dried Longan Wine fermented with monocultures of S. cerevisiae and T. delbrueckii produced a total volatile aroma content of 393.21 mg/l and 383.20 mg/l, respectively. Simultaneous culture of the two organisms produced the highest total volatile aroma content, that affected most volatile compounds including isobutanol, ethyl acetate, ethyl decanoate, ethyl heptanoate, ethyl hexanoate, ethyl pentanoate, isoamyl acetate, and isobutyl acetate. Of the four treatments, the sequential culture possessed the highest total phenolic content (5.80 mg gallic acid equivalents (GAE)/ml). In addition, the total phenolic content significantly correlated with the antioxidant activity of the Golden Dried Juice and Golden Dried Longan Wine. These results suggest that co-cultures of the two organisms used in the production of the Golden Dried Longan Wine may improve the intensity and complexity of its aroma.

• Food Science and Preservation
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• v.13 no.5
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• pp.548-554
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• 2006

This study investigated the effect of the addition of germinated brown rice extract powder (0, 0.67, 3.35 and 6.70%) to the fermentation of Korean cabbage kimchi. During the fermentation of Korean cabbage kimchi with GBREP, content of total free amino acid and essential amino acid was showed higher value by increasing the addition of GBREP. In particular, ${\gamma}$-aminobutyric acid (GABA) content of Korean cabbage kimchi, prepared with 6.70% GBREP was 2 times higher than control Korean cabbage kimchi. By increasing the content of GBREP, total phenol content was showed high value and the content was more increased during fermentation except control Korean cabbage kimchi. By increasing the content of GBREP, electron donating activity and superoxide radical scavening activity were showed higher value and then showed maximum scavening activity on palatable period. Nitrite-scavenging ability of Korean cabbage kimchi with GBREP was higher than control Korean cabbage kimchi and showed the highest scavenging ability at pH 1.2.