• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.10
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• pp.1301-1306
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• 2008

The physiological and microbiological characteristics of various mul-kimchis prepared with omija (Schiznadra chinensis) water extract (1, 2, 3 v/w%) (omija mul-kimchi ) or water (control) were investigated during fermentation for 21 days at $10^{\circ}C$. The pH of omija mul-kimchi was lower than that of control and lowered with increasing the concentration of omija between 1% and 3%. The pH did not change significantly during fermentation in omija mul-kimchi compared with control. The changes in titratable acidity were similar in pH. The change of total microbs and lactic bacteria during fermentation was similar in various mul-kimchis and the viable cell numbers in omija mul-kimchi were lower than in control. The viable cell of mul-kimchi decreased with increasing the concentration of omija water extract. The texture of various mul-kimchi such as hardness, cohesiveness, chewiness and springiness, was decreased but the texture of 1% omija mul-kimchi was maintained significantly higher than that of control during fermentation. The DPPH radical and nitrite scavenging activity of omija mul-kimchi were higher than those of control and the activities increased with increasing concentrations of omija water extract. The sensory quality of 1% omija mul-kimchi showed the highest value in taste and overall acceptability among the tested mul-kimchis.

• Korean Journal of Microbiology
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• v.50 no.3
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• pp.227-232
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• 2014

In this study, Gluconacetobacter sp. gel_SEA623-2 isolated from citrus that produces bacterial cellulose was used to examine the effect of initial concentration of acetic acid and mixed culture inoculated with Lactobacillus plantarum KCCM 80077 on productivity of bacterial cellulose. In mixed culture added with 0.5% acetic acid, the viable cell count increased from $2.4{\times}10^6CFU/ml$ to $1.1{\times}10^7CFU/ml$ after 14 days of culture, and total acidity was about 0.3% higher than single culture added with 0.5% acetic acid, which implies that additional lactic acid was produced by L. plantarum KCCM 80077. In single culture, although bacterial cellulose productivity was higher when the initial concentrations of acetic acid were 0.0% and 0.5%, than when it was 1.0%, there was no significant difference. However, in mixed culture, adding 0.5% acetic acid resulted in dry weight of $37.83{\pm}6.81g/L$ and thickness of $10.33{\pm}0.58mm$, showing a significant difference from that of single culture added with 1% acetic acid, $28.40{\pm}1.23g/L$ and $7.50{\pm}0.50mm$ (P<0.05).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.492-501
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• 2016

This study was conducted to investigate the physiochemical characteristics of Cheongju prepared using different types of rice (rice and glutinous rice) according to addition rate of Nuruk during low temperature fermentation. The characteristics of Cheongju prepared using three different temperatures ($10^{\circ}C$, $18^{\circ}C$, $25^{\circ}C$) were compared. After fermentation for 30-50 days, the pH of mash prepared at lower temperature was lower, as was that of mash made from rice relative to that prepared using glutinous rice. The total acidity was formed at lower temperature and generated in mashing prepared by glutinous rice. The organic acid content of mash made from rice at $18^{\circ}C$ was lowest, while that of mash prepared from glutinous rice was lowest at $10^{\circ}C$. The fermentation speed was lowest at $10^{\circ}C$; however, low temperature fermentation resulted in the highest alcohol content. The mash prepared from glutinous rice showed faster fermentation than that made from rice. In addition, the pH was lower when lower levels of Nuruk were added and higher in mash made from glutinous rice than that prepared from rice. The lower addition rate of Nuruk also showed a lower sugar content and final alcohol content. The levels of citric acid and lactic acid were higher, while those of succinic acid, acetic acid, and ethyl acetate were lower when lower levels of Nuruk were added. The mash prepared from glutinous rice showed a higher alcohol content than that made from rice.

• Korean journal of food and cookery science
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• v.14 no.4
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• pp.421-429
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• 1998

The effect of glutinous rice paste on the physicochemical, microbiological, and sensory characteristics of Puchukimchi during fermentation was investigated. Puchukimchi is a kind of korean kimchi made with Leek (Allium odorum L.). Puchukimchi made with various concentrations (0.0, 0.5, 1.0, 2.0, 3.0%) of glutinous rice paste were fermentated at 10$^{\circ}C$ up to 45 days. As a fermentation progressed, pH decreased in all of the treatments, while total acidity increased. By increasing the concentrtion of glutinous rice paste added, an increase of total acidity was noted from Puchukimchi. The reducing sugar content in most samples was decreased during fermentation, however, 1.0% treatment showed a relatively slow decrease. The total vitamin C content increased sharply at the 2nd-day of fermentation and then, gradually decreased especially from the 8th-day following a sigmoidal changing pattern. The total vitamin C content was the highest in Puchukimchi made with 1.0% glutinous rice paste. The counts of lactic acid bacteria increased remarkably and then decreased gradually after optimum ripening period, i.e., the palatable period of Puchukimchi during fermentation.

• Korean Journal of Food Science and Technology
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• v.33 no.2
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• pp.178-183
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• 2001

This study was conducted to determine the optimal extraction condition of temperatures and kinds of extraction solvent, and antimicrobial activity of ethanol extract of Quercus mongolica leaf and organic acid against foodborne microorganisms. The antimicrobial activity of ethanol extract at $60^{\circ}C$ for 6 hour against foodborne microorganisms was stronger than those at $30^{\circ}C\;and\;90^{\circ}C$. Also, the ethanol extract showed stronger antimicrobial activity than those of water and methanol extract. The minimal inhibitory concentrations of the ethanol extract of Quercus mongolica leaf against B. cereus and L. monocytogenes, was $62.5{\sim}125\;{\mu}g/mL$ but, the minimal inhibitory concentration was $250\;{\mu}g/mL$ against S. typhimurium and P. aeruginosa and over $500\;{\mu}g/mL$ against E. coli O157:H7, respectively. The minimal inhibitory concentrations of the lactic, citric, acetic acid and the ethanol extract of Quercus mongolica leaf against B. cereus and L. monocytogenes was 2500, 5000, 1250 and $125\;{\mu}g/mL$, respectively. The combined effect of each organic acid and the ethanol extract against B. cereus was not observed but, synergistic effect was observed against L. monocytogenes. In the meantime, when the ethanol extract was combined with each organic acid at sub-lethal concentration, the combination did not increase the inhibitory effect of the most active single compound alone against E. coli O157:H7, respectively.

• Applied Biological Chemistry
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• v.31 no.2
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• pp.154-161
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• 1988

In order to improve the quality of amino acid soysauce, this experiment was carried out as follows; koji added amino acid soysauce(KAAS) was prepared by addition of defatted soybean and meal koji into amino acid soysauce containing $0.5%{\sim}1.5%$ of total nitrogen. Various physicochemical characteristics of KAAS during aging were determined. Total nitrogen, amino-nitrogen, specific gravity, pure extract, total acidity and color were high in KAAS at high total nitrogen. After one month aging, reducing sugar was high in KAAS at high total nitrogen, but pH was high in KAAS at low total nitrogen. Ethyl alcohol was 2.07% in KAAS at 0.5% of total nitrogen after five months aging and 1.4% in KAAS at 1.5% of total nitrogen. Levulinic acid and lactic acid were high in KAAS at low total nitrogen. The results obtained above summarized as the quality of KAAS were highly good at $0.5{\sim}0.7%$ of total nitrogen after two or three months aging.

• Food Science and Preservation
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• v.18 no.6
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• pp.961-966
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• 2011

This research was carried out to evaluate the value of tofu containing mushroom as a immunomodulator. Tofu was made using $CaSO_4{\cdot}2H_2O$ or Lactobacillus extract as a coagulant after adding powder of fruit bodies or mycelia of Letino edodes and Lepista nuda to soybean milk. Proximate compositions of tofu and tofu containing mushroom were analyzed. Levels of interferon ${\gamma}$ (IFN-${\gamma}$), interleukin 4 (IL-4) and tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) in culture media of lymphocytes collected from mouse spleens after being injected with mushroom, regular tofu, or tofu made with mushroom were measured by sandwich ELISA. In addition, concentrations of IgG1, IgG2a and IgE in plasma or lymphocyte culture media were analyzed. Crude protein, crude lipid and crude ash were decreased in tofu containing mushroom but phosphorus was increased significantly. IFN-${\gamma}$ concentration was significantly decreased in mice injected with fruit body or tofu alone. IL-4 level was decreased significantly in mice injected with tofu containing fruit body of L. edodes. However, TNF-${\alpha}$ was increased in mice injected with tofu containing fruit body of L. edodes. Plasma levels of IgG1 were increased in almost all groups, while there was no significant change in IgG2a levels among treated mice groups. Concentrations of IgG1 and IgG2a were increased significantly in lymphocyte culture media of mice injected with tofu containing mushroom. Plasma levels of IgE level was significantly increased in mice injected with tofu or fruit body of L. edodes, but not in mice treated with tofu containing mushroom. These results showed that tofu with mushroom affected immune activities, and it seems valuable to consider developing the mixture of tofu and L. edodes as an immunomodulator.

• Food Science and Preservation
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• v.16 no.6
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• pp.953-958
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• 2009

The antimicrobial activities, antioxidant effects, and total polyphenol contents of extracts of Prickly Pear Opuntia ficus indica, were investigated. In antimicrobial activity assays of solvent extract fractions, methanol and butanol extracts showed higher activities than did hexane and ether extracts. The stem showed a higher antimicrobial activity than did the fruit. When the antimicrobial activities of fruit and stem extracts was tested using 10 bacterial strains, strong activity was evident against Escherichia coli, with a lowest minimum inhibitory concentration of 100 mg/disk. However, no antimicrobial activities against lactic bacteria or yeasts were evident, even with disks containing more than 500 mg extract/disk. Antimicrobial substances in butanol extracts of fruit and stem maintained activity after heating at $100^{\circ}C$ for 30 min and were not affected by changes in pH. DPPH free radical-scavenging activities of solvent extracts were in the order of water, ethyl acetate, butanol, ether, and ethanol. The stem showed greater DPPH free radical-scavenging activity than did the fruit. The total polyphenol contents in fruit and stem were 520.57 and 203.26 mg%, respectively.

• Microbiology and Biotechnology Letters
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• v.39 no.1
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• pp.77-85
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• 2011

The antibacterial activities of silver nanoparticles (Ag-NPs) were studied with respect to Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli by observing the bacterial cells treated or not with Ag-NPs by FE-SEM as well as measuring the growth curves, formation of bactericidal ROS, protein leakage, and lactate dehydrogenase activity involved in the respiratory chain. Bacterial cells were treated with Ag-NPs powder, and the growth rates were investigated under varying concentrations of Ag-NPs, incubation times, incubation temperatures, and pHs. As a result, S. aureus and E. coli were shown to be substantially inhibited by Ag-NPs, and the antibacterial activity of Ag-NPs did not fluctuate with temperature or pH. These results suggest that Ag-NPs could be used as an effective antibacterial material.

• Korean Journal of Food Science and Technology
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• v.10 no.2
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• pp.231-236
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• 1978

It has been investigated that preparation of cheese-like product from defatted soybean milk and changes during 6 weeks' ripening. Obtained results were as follows: 1. Defatted soybean milk was fermented at $37^{\circ}C$ for 4 hours with Streptococcus lactis YUFE L-4 without addition of any other carbon sources. 2. Optimum concentration of coagulant such as $MgCl_2{\cdot}6H_2O$ and $CaCl_2$ were 0.0125M and 0.0375M, respectively. 3. Coagulating time for 30 minutes was sufficient to make curd. 4. Optimal reaction temperature for coagulating were $50^{\circ}C$. 5. After 6 weeks' ripening, moisture content was approximately $62{\sim}63%$. Water and 10%-TCA soluble nitrogen contents of soybean cheese with Asp. saitoi protease were higher than those of Mucor rennet. Water soluble nitrogen content of Asp. saitoi protease cheese was 50.5% and 10%-TCA soluble nitrogen was 27.5%.