• Journal of Life Science
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• v.24 no.1
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• pp.46-53
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• 2014

Lactobacillus sakei 383, which showed the highest GABA content in fermented soycurd, survived in artificial gastric fluid (pH 3.0) up to 3 h, and the survival rate was 88%. L. sakei 383 was tolerant to bile juice during incubation in MRS broth with 0.3% oxgall, and the survival rate was 99%. The survival ratio of L. sakei 383 was high in media containing less than 6% NaCl. L. sakei 383 produced an antibacterial substance against various pathogens, including Listeria monocytogenes, Bacillus cereus, Staphylococcus aureus, Escherichia coli, and Salmonella typhi. The quality characteristics of soycurd fermented with L. sakei 383 were measured during the fermentation period. The viable cell number reached a peak ($10^{11}CFU/ml$) 36 h after fermentation and then slowly decreased. According to the fermentation time of L. sakei 383, the acidity of soycurd increased and the pH decreased until 12 h, and they were maintained thereafter. The moisture, crude ash, crude protein, crude fat, and crude fiber content was 94.88, 0.22, 2.38, 1.16, and 0.03%, respectively. The content of total and reducing sugar was comparatively higher in the soycurd fermented with L. sakei 383 than in nonfermented soycurd. The essential and nonessential amino acid content was 11.2 and 38.65 mg/100 g.

• Food Science and Preservation
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• v.20 no.5
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• pp.705-711
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• 2013

Gamma amino butyric acid (GABA), known as a non-protein amino acid and major inhibitory neurotransmitter in the brain, has several functional properties such as neurotransmission, induction of hypotension, tranquilizer, and diuretic effects. The purpose of this study was to isolate and identify lactic acid bacteria, producing high GABA in fermented soy curd. Thirty-two strains of tofu-forming lactic acid bacteria were isolated from kimchi which a traditional Korean food fermented with many kind of microorganism. Among 32 strains, four strains (strain No. 10, 104, 214, 249) formed firm soycurd. In order to select lactic acid bacteria having high GABA producing potential, the isolated strains were cultured in the soymilk and fermented for 48 hr at $37^{\circ}C$. A strain No. 383, which showed highest GABA contents in fermented soycurd, was identified as L. sakei by 16S rDNA sequencing and API analysis, and named as L. sakei 383. L. sakei 383 showed optimal growth up to 24 hr at $35^{\circ}C$ in MRS broth. The optimal time and temperature for GABA production were 18 hr and $35^{\circ}C$ in soymilk. In the optimal condition time and temperature, GABA content of fermented soycurd by L. sakei 383 was 8.65 mg/100 g.

• Journal of Life Science
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• v.29 no.4
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• pp.478-483
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• 2019

The use of fermented soy curd as a functional substance has been actively studied due to the anti-inflammatory and antiallergic activity of soybean protein hydrolyzate by enzymes of lactic acid bacteria. The present study investigated the potential of soy curd as a treatment for atopic dermatitis (AD). Pediococcus inopinatus Y2 (P. inopinatus Y2) lactic acid bacteria were inoculated into soy milk and fermented ($30^{\circ}C$, 24 hr). Changes in body weights, ear thicknesses, IgE concentrations, and weights of immune organs in ICR female mice were quantified. Moderate weight gain occurred in most of the groups. The ear thickness was lowest in the untreated group (no group), and it was allergic and thickened in the phthalic anhydride (PA) treatment group. Based on visual observations, as compared with the skin condition of the PA-induced AD group, the skin condition of the animals in the fermented soy curd (FSC) group was improved. Therefore, FSC by lactic acid bacteria seemed to improve AD. Based on the comparison of the weights of the spleen, thymus, and lymph nodes, as well as the results of the IgE analysis, soy milk, in addition to FSC, had a therapeutic effect. However, the antiallergy effects of FSC in terms of AD were far superior to those of soy milk. These results indicated that FSC can be used as a treatment for AD.