• 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.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.4
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• pp.348-352
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• 1994

Soybean seed consists of two major storage protein, the 7S and 11S globulins. For improving the quality of soybean seed protein, an increase of 11S/7S ratio would be a desirable objective because the 11S globulin contains much more the sulfur-containing amino acids than the 7S globulin. In this study, some soybean varieties were used to investigate the analyzing method for 7S and 11S globulins. 7S and 11S globulins couble be fractionated by their different solubilities in tris buffers. Adjusting the pH and tris concentration were major factors affecting the precipitation of the two globulins. And it was possible to screen the soybean genotypes having aberrant subunit compositions of the two globulins by an sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of total soybean proteins. The ratio of 11S to 7S globulin ranged from 1.29 to 1.38. This paper also dealed with the contribution of protein components in soybean seeds to the physical properties of soycurd. It indicated that the soycurd from crude 11S was remarkably harder than that from crude 7S, and springiness and cohesiveness were slightly higher in soycurd having higher proportion of 11S. So, it may concluded that proportion of protein components in soybean seed can be important factor which controls the suitability for soycurd or other foods.

• 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.

• Proceedings of the Korean Society of Crop Science Conference
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• 2005.10b
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• pp.320-321
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• 2005

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48
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• pp.49-57
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• 2003

There is much evidence suggesting that compounds present in soybean can prevent cancer in many different organ systems. Especially, soybean is one of the most important source of dietary saponins, which have been considered as possible anticarcinogens to inhibit tumor development and major active components contributing to the cholesterol-towering effect. Also they were reported to inhibit of the infectivity of the AIDS virus (HIV) and the Epstein-Barr virus. The biological activity of saponins depend on their specific chemical structures. Various types of triterpenoid saponins are present in soy-bean seeds. Among them, group B soyasaponis were found as the primary soyasaponins present in soybean, and th e 2, 3-dihydro-2, 5-dihydroxy-6- methyl-4H-pyran-4-one(DDMP)-conjugated soyasaponin $\alpha\textrm{g}$, $\beta\textrm{g}$, and $\beta$ a were the genuine group B saponins, which have health benefits. On the other hand, group A saponins are responsible for the undesirable bitter and astringent taste in soybean. The variation of saponin composition in soybean seeds is explained by different combinations of 9 alleles of 4 gene loci that control the utilization of soyasapogenol glycosides as substrates. The mode of inheritance of saponin types is explained by a combination of co-dominant, dominant and recessive acting genes. The funtion of theses genes is variety-specific and organ specific. Therefore distribution of various saponins types was different according to seed tissues. Soyasaponin $\beta\textrm{g}$ was detected in both parts whereas $\alpha\textrm{g}$ and $\beta$ a was detected only in hypocotyls and cotyledons, respectively. Soyasaponins ${\gamma}$g and $\gamma\textrm{g}$ were minor saponin constituents in soybean. In case group A saponins were mostly detected in hypocotyls. Also, the total soyasaponin contents varied among different soy-bean varieties and concentrations in the cultivated soy-beans were 2-fold lower than in the wild soybeans. But the contents of soyasaponin were not so influenced by environmental effects. The composition and concentration of soyasaponins were different among the soy products (soybean flour, soycurd, tempeh, soymilk, etc.) depending on the processing conditions.

• Journal of Life Science
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• v.21 no.3
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• pp.358-367
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• 2011

Soybean is known to contain various phytochemicals that are related to anti-oxidant, anti-inflammatory and anti-obesity effects in mice and humans. The anti-obesity effect of by-product extracts from soybean on the differentiation of 3T3-L1 pre-adipocytes to adipocytes was investigated by suppressing adipocyte differentiation and lipid accumulation with Oil Red-O assay and quantitative PCR. In inducing differentiation of 3T3-L1 pre-adipocytes in the presence of an adipogenic cocktail, isobutylmethylanthine (IBMX), dexamathasone, and insulin, treatment with filtrated soybean soaked water, soybean milk, and soycurd residue from soybean curd processing significantly decreased mRNA expression of obesity-related gene such as PPAR${\gamma}$, Fabp4, and Scd1, adipsin, apolipoprotein (APOE) and adiponectin (ADIPOQ) without any significant cytotoxicity. We also determined the well-known isoflavones in soybean, such as daidzein and genistein, in the by-product extracts. Taken together, we suggest that soybean by-product extract showed anti-obesity effect by suppressing adipocyte related gene expression, and that by-products collected during soybean curd processing may be a good candidate as an ingredient in health care products.

• 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.