• Korean Journal of Microbiology
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• v.52 no.2
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• pp.202-211
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• 2016

This study evaluated the changes of phytoestrogen contents and antioxidant activities of soybean-powder milk (SPM) prepared from yellow soybean during fermentation with Lactobacillus plantarum P1201. In consequence, the levels of total phenolic and isoflavone-aglycone contents, ABTS and DPPH radical-scavenging activities, and FRAP assay values increased, while isoflavone-glycoside contents decreased during fermentation. The highest levels of daidzein, glycitein, and genistein were present in the Daepung SPM at concentrations of 177.92, 20.64, and $106.14{\mu}g/g$, respectively after 60 h of fermentation. Moreover, Daepung SPM showed the highest DPPH radical-scavenging activity of 48.54%, an ABTS radical-scavenging activity of 99.25%, and a FRAP assay value of 0.84 at the end of fermentation. The fermented Daepung SPM possessed highest isoflavone aglycone contents and antioxidant activities, which can be utilized for the development of functional foods.

• Journal of Applied Biological Chemistry
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• v.61 no.3
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• pp.245-255
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• 2018

The research was aimed to analyze the functional constituents (GABA and isoflavone), radical (2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and hydroxyl) scavenging activities and enzyme (${\alpha}-glucosidase$ and lipase) inhibitory effects of soypowder milk (SPM) and fermented soy-powder milk (FSPM) with varied Lactobacillus brevis. Ten ${\gamma}-aminobutyric$ acid (GABA) producing lactic acid bacteria that showed 96-99% similarity with L. brevis, according to 16S rRNA gene sequence analysis, were isolated from fermented kimchi. The conversion rates of GABA were obtained 66.96-93.51, 63.76-84.58, and 57.05-69.75% in monosodium glutamate, gluten and soy protein, respectively. The levels of pH and glutamic acid of FSPM were found lower than those of SPM, but the acidity and GABA contents were higher. The GABA conversion rate of FSPM with BMK484 strain was attained the highest 69.97%. The contents of isoflavone glycoside ($1290.93{\mu}g/g$) was higher in SPM, but the content of isoflavone aglycone ($287.27-501.9{\mu}g/g$) was higher in FSPM. The levels of isoflavone aglycone such as daidzein, glycitein and genistein, were found as the highest 240.2, 61.24 and $200.45{\mu}g/g$, respectively, when FSPM was made with BMK484 strain. The DPPH, ABTS and hydroxyl radical scavenging and ${\alpha}-glucosidase$ and pancreatic lipase inhibitory activities of FSPM made with BMK484 strain were the relatively higher 60.31, 88.10, 61.25, 52.71, and 39.37%, respectively. Therefore, the L. brevis can be used as a material capable of simultaneously enhanced GABA and isoflavone aglycone in FSPM.

• Korean Journal of Microbiology
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• v.51 no.3
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• pp.231-240
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• 2015

In this study, a total of 16 conjugated linoleic acid (CLA) producing lactic acid bacteria (LAB) were isolated from fermented foods. Among those strains, the S48 and P1201 strains were capable of producing higher CLA contents than other LABs. The two strains were classified as Lactobacillus plantarum based on morphological, physiological, chemotaxonomic, and molecular-genetic properties. The survival rates of these strain appeared to be 59.57% and 62.22% under artificial gastric conditions after 4 h at pH 2.5, respectively. These strains produced the cis-9, trans-11, and trans-10, cis-12 CLA isomers from 8% skim milk medium supplemented with the different free LA concentration at $37^{\circ}C$ for 48 h and the production of two CLA isomers constantly increased in the growth until 48 h of incubation. After 48 h of fermentation, the levels of CLA appeared highest in steamed soy-powder milk than fresh and roasted soy-powder milks. In particular, the CLA contents were produced $183.57{\mu}g/ml$ and $198.72{\mu}g/ml$ from steamed soy-powder milk after fermentation (48 h) with S48 and P1201 strains, respectively.

• Food Science and Preservation
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• v.25 no.1
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• pp.7-18
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• 2018

In this study, soy-powder yogurt (SPY) with enhanced levels of ${\gamma}$-aminobutyric acid (GABA) and isoflavone aglycone was produced from sprouting high-protein soybeans (HPSs). The fermented steam-HPS sprouts (0 to 4 cm) were fermented (72 h) with Lactobacillus brevis, and the total free amino acids (FAAs) of the formed mixtures were determined to be 79.53, 489.93, 877.55, 780.53, and 979.97 mg/100 mL in the fermented HPS (FHPS), and the fermented steam-HPS with 0 cm (FSHPS-0), 1 cm (FSHPS-1), 2 cm (FSHPS-2), and 4 cm sprouting lengths (FSHPS-4), respectively. The levels of glutamic acid (GA) and GABA were observed to be the highest, 100.31 and 101.60 mg/100 mL, respectively, in the unfermented HPS (UFSHPS-1, 1 cm) and FSHPS-1 sprouts, respectively. Moreover, the total contents of the isoflavone glycoside form decreased proportionally to the increasing total levels of isoflavone aglycones after fermentation in FSHPS-0, FSHPS-1, FSHPS-2, and FSHPS-4. The levels of isoflavone aglycones were detected as 350.34, 289.15, 361.61, 445.05, and $491.25{\mu}g/g$ in FHPS, FSHPS-0, FSHPS-1, FSHPS-2, and FSHPS-4, respectively. While FSHPS-1 exhibited the highest DPPH (63.28%) and ABTS (73.28%) radical scavenging activities, FSHPS-4 contained the highest isoflavone aglycone ratio (81.63%). All in all, the FSHPS-1 mixture prepared in this study exhibited high GABA content and functional prosperity, thereby making it suitable for potential applications in the soy-dairy industry.