• The Korean Journal of Food And Nutrition
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• v.27 no.4
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• pp.699-705
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• 2014

This study was conducted to select the coagulant for konjac processing and to identify the antibacterial activity on foodborn pathogens by concentration of $Ca(OH)_2$. In rheological properties such as hardness, gumminess and chewiness, konjac jelly were increased by progressing coagulation regardless of coagulant. In mineral contents, the Ca content of konjac jelly made with $Ca(OH)_2$ was significantly higher than that of NaOH. On the contrary, the Na content of konjac jelly made with NaOH coagulant was significantly higher than that of $Ca(OH)_2$. There were no significant differences in the Mg and P contents according to coagulant. In sensory evaluation, there were no significant differences in the color, flavor, taste, texture and overall quality according to coagulant. The antimicrobial activities of Staphylococcus aureus, E. coli, Salmonella typhimurium were inhibited in proportion to the concentration of $Ca(OH)_2$. According to the manufacturing process of konjac jelly, the change in microorganism was not found after molding.

• Journal of Food Hygiene and Safety
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• v.23 no.4
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• pp.330-337
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• 2008

Betarich carrots were washed at various hypochloric acid(HCA) concentration and steeping time and packed in PE bag keeping at $8^{\circ}C$ for 12 days, in order eventually to examine microbiology, firmness, surface color, whiteness index(WI) and sensory quality. It was found that total bacterial counts at T-II and T-III with the 3 minute steeping were $4.37{\pm}0.19\;\log\;CFU/g$ and $4.27{\pm}0.13\;\log\;CFU/g$ respectively, showing slight decrease compared to control condition. E. coli was not detected at all treatments but less coliforms were detected at the 8-day treatments of T-II and T-III. Treatment of 3-minute steeping showed smaller reduction in firmness than that of I-minute steeping at 12-days, and T-1 (T-3) had the largest (smallest) reduction among them. It was also found that during the treatment the L-value showed decreasing trend, but the parameter a- and b-value showed increasing trend. WI increased, and its change was small with the increase in HCA concentration. The sensory quality check after 8 day storage showed that evaluation of the off-flavor appeared to be significantly high (p<0.05) at both non-treatment and HCA treatment. On the basis of the results above, it is likely to be more effective to prolong the period of circulation of beta rich carrots if you use HCA over 50 ppm for washing betarich carrots. This study will contribute to improve safety and quality in circulation of beta rich carrots.

• Polymer(Korea)
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• v.36 no.1
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• pp.71-75
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• 2012

In this study, silver nanoparticles (AgNPs) have been prepared by using aqueous $AgNO_3$ solution in the poly(vinyl alcohol) (PVA) hydrogels. PVA powders were dissolved in deionized water, and then irradiated by gamma-ray with a radiation dose of 50 kGy to make hydrogels. PVA hydrogels were dipped into 0.01 and 0.05 M $AgNO_3$ solution for 1 h respectively. After that, the swollen hydrogels were irradiated by gamma-ray at various doses to form AgNPs. UV-vis analysis indicated that the concentration of Ag NPs was enhanced by increasing absorbed dose and the concentration of $AgNO_3$. FE-SEM measurements provided further evidence for the successful formation of Ag NPs in PVA hydrogels. Also, the antibacterial effect of PVA hydrogels stabilized AgNPs against Gram-negative bacteria (S.aureus and E.coli) in liquid as well as on solid growth media has been investigated. The AgNPs consolidated in PVA hydrogel networks have an excellent antibacterial effect.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.112-112
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• 2022

This study aims to confirm the possibility of using the invasive alien plants in Jeju as a functional biomaterial. To achieve this purpose, 70% ethanol extract and solvent fractions were prepared for five invasive alien plants (Hypochaeris radicata, Rumex acetosella, Humulus japonicus Siebold & Zucc., Solanum viarum, Lactuca scariolar) and their antioxidant, antibacterial anti-inflammatory and anti-obesity effects were investigated. The DPPH radical scavenging activity of ethanol extract from invasive alien plants was shown in the order of Rumex acetosella > Hypochaeris radicata > Humulus japonicus. Antimicrobial activity of ethanol extract against food poisoning bacteria (4 species) and oral cavity-induced microorganisms (6 species) was measured. As a result, the extract of Humulus japonicus showed high antibacterial effects against food poisoning bacteria (E. coli, V. parahaemolyticus) and oral microbes (L. casei, S. epidermidis, E. faecalis). In LPS-induced RAW 264.7 cells, the anti-inflammatory effect of ethanol extract from invasive alien plants was investigated. As a result, the NO production inhibition activity was highest in the Rumex acetosella and the Humulus japonicus Siebold & Zucc. ethanol extract, and the NO production inhibition activity was concentration-dependent. In addition, the Rumex acetosella and the Humulus japonicus Siebold & Zucc. ethanol extract showed a concentration-dependent inhibitory effect on cytokine (IL-6) production. These extracts also showed inhibitory activity of COX-2, an inflammatory protein. This suggests that NO production inhibition activity by the extract of invasive alien plants is the result of inhibition of iNOS and COX-2 expression. Currently, organic solvent fractions of crude extract are manufactured and the investigation of active ingredients is continuing along with evaluation of biological activity such as anti-inflammatory. These results are expected to be a major data for the study on the separation and utilization of active ingredients with antioxidant, antibacterial and anti-inflammatory effects using foreign plant crude extract and solvent fractions, and are highly likely to be applied to the development of functional food and cosmetics materials.

• Microbiology and Biotechnology Letters
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• v.37 no.2
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• pp.118-124
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• 2009

Esterase EM2L8 gene isolated from deep sea sediment was expressed in Escherichia coli BL21 (DE3) and the esterase activity of the cell-free extract was assayed using p-nitrophenyl butyrate-spectrophotometric method. Its optimum temperature was $40-45^{\circ}C$ and 45% activity of the maximum activity was retained at $15^{\circ}C$. The activation energy at $15-45^{\circ}C$ was calculated to be 4.9 kcal/mol showing that esterase EM2L8 was a typical cold-adapted enzyme. Enzyme activity was maintained for 6 h and 4 weeks at $30^{\circ}C$ and $4^{\circ}C$, respectively. When each ethanol, methanol, and acetone was added to the reaction mixture to 15% concentration, enzyme activity was maintained. In the case of DMSO, enzyme activity was kept up to 40% concentration. (S)-4-Chloro-3-hydroxy butyric acid is a chiral intermediate for the synthesis of Atorvastatin, a hyperlipemia drug. When esterase EM2L8 (40 U) was added to buffer solution (1.2 mL, pH 9.0) containing ethyl-(R,S)-4-chloro-3-hydroxybutyrate (38 mM), it was hydrolyzed into 4-chloro-3-hydroxy butyric acid with a rate of $6.8\;{\mu}mole/h$. The enzyme hydrolyzed (S)-substrate more rapidly than (R)-substrate. When conversion yield was 80%, e.e.s value was 40%. When DMSO was added, hydrolysis rate increased to $10.4\;{\mu}mole/h$. The plots of conversion yield vs e.e.s in the presence or absence of DMSO were almost same, implying that the reaction enantioselectivity was not changed by the addition of DMSO. Taken together, esterase EM2L8 had high activity and stability at low temperatures as well as in various organic solvents/aqueous solutions. These properties suggested that it could be used as a biocatalyst in the synthesis of useful pharmaceuticals.

• Korean Journal of Food Science and Technology
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• v.35 no.3
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• pp.373-378
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• 2003

This research was conducted to investigate the possibilities of usage of rose (Rosa hybrida L. cv. Mary Devor) by examining th antioxidative and antimicrobial activities of extracts with various levels of ethanol concentrates. Proximate composition, dietary fiber, and flavonoids contents were analyzed, and total antioxidant status and yield ratios of extraction of rose were measured. The rose extracts were extracted in different level of ethanol concentrates (0, 75, 85, 95%), and peroxide value, acid value, and TBA value were investigated in different level of concentrates of extracts added and time duration of storage. The results were as follows; derivation period from measuring peroxide value showed that the rose (Petal & Calyces) extract-added group showed longer derivation period than the control group, tocopherol-added, or BHT-added groups, and it proved to be a highly effective antioxidant as a result. It showed the longest derivation period especially when 85% ethanol extract was added with concentration of 0.05%. For the acid values and TBA values of the extract added oil, the rose extract-added group and BHT-added group showed lower values than the control group and tocopherol-added group as th length of time for storage becomes longer. In fact, the rose extracts suggested the possibility to be used as a natural antioxidants as it showed high antioxidative effect similar to BHT. Overall, the rose extracts from each solvent showed high antimicrobial effects against Escherichia coli, Salmonella typhimurium, Staphylococcus aureus than control group. Especially, 85% ethanol extract showed significantly high antimicrobial effect against Escherichia coli.

• KSBB Journal
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• v.11 no.2
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• pp.132-139
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• 1996

The growth of recombinant E. coil and by-product production were investigated. D-cycloserine was added to increase the secretion of ${\alpha}$-amylase from recombinant E.coil. Even though cell growth was increased for optimal d-cycloserine concentration $0.1g/\ell$, extracellular ${\alpha}$-amylase activity remained almost the same as the case without d-cycloserine. It is important to achieve the high cell density for commercial production of methaboliles including ${\alpha}$-amylase. To achieve this goal, culture conditions should be selected carefully and optimized considering cell growth and by-products production. In cultivating retombinant E. coli, lactic acid and acetic acid turned out to be important by-product which affected cell yield and growth rate.

• Journal of Life Science
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• v.19 no.9
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• pp.1245-1250
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• 2009

Beimu (Fritillaria thunbergii Miquel), a bulbous plant of Liliaceae found in Korea, Japan and China, has been used as an antitussive and expectorant agent, and is also useful in alleviating stonsillitis and bronchiolitis. Most researches have been focused on micro-propagation and plant regeneration, component analysis, and dormancy relieving of beimu. Reports regarding the biological activity of beimu, such as anti-Helicobacter pyroli or platelet aggregation inhibition activity, are few and not widely available. In this study, methanol extract and its organic solvent fractions were prepared from Fritillaria thunbergii Miquel and their antimicrobial, antithrombin, and antioxidant activities were evaluated, respectively. The methanol extract contained lots of water-soluble materials (58.98%) and hexane-soluble oils (14.85%). The ethylacetate and butanol fraction at $500{\mu}g$/disc concentration showed strong antibacterial activity against tested bacteria, except Escherichia coli. Antifungal activity was not observed in methanol extract and its fractions. The hexane, ethylacetate and butanol fractions showed strong antithrombin activity at 4.8 mg/ml concentration. Especially, the ethylacetate fraction showed 95.4 sec of thrombin time at a concentration of 1.2 mg/ml, which is comparable to aspirin, a widely used antithrombosis agent. For antioxidation activity, the ethylacetate and butanol fraction showed good 1,1-diphenyl-2-picryl hydrazyl scavenging activity ($IC_{50}$ of $344{\sim}368{\mu}g$/ml). In superoxide dismutase-like activity and reducing power, the fractions showed $20{\sim}25%$ of vitamin C, and $51{\sim}54%$ of butyl hydroxytoluene, respectively.

• Korean Journal of Veterinary Service
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• v.22 no.4
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• pp.411-418
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• 1999

In this studies, the ability of chlorine and lactic acid to reduce bacterial population of the pathogenic microorganisms were examined on artificially inoculated chicken skin. About 10$^{5}$ cells of staphylococcus aureus, salmonella enteritidis, listeria monocytogenes and escherichia coli O157:H7 were inoculated in chicken skin. The contaminated samples were washed for 1 min with sodium hypochlorite solutions that contained 2, 5, 10, 20 and 50mg/$\ell$ available chlorine and counted number of the agents. Viable population were no significantly difference (p$\geq$0.05) between concentration of chlorine and strains of the pathogens. In the samples inoculated with pathogens were washed in 20mg/$\ell$ chlorine and then stored at $^5{\circ}C$ for up to 10 days, the initial counts of psychrotrophs and aerobic plate counts were 4.02 to 4.36 log cfu/$\textrm{cm}^2$ and increased slightly in course of time. But 10 days after, the pathogens were a little reduced from 3.66~4.91 log cfu/$\textrm{cm}^2$ to 2.54~4.66 log cfu/$\textrm{cm}^2$. In the case of washed skin with solution of 20mg/$\ell$ chlorine and 0.5% lactic acid then store at $^5{\circ}C$ for up to 10 days, population of psychrotrophs and aerobic plate counts on chicken skin were markedly reduced immediately after treatment, but the numbers of contaminants were slightly increased after 6 and 8 days. Specifically, numbers of St aureus, S enteritidis, L monocytogenes and E coli O157:H7 were reduced to 0.5, 0.4, 0.3 and 1.15 log cfu/$\textrm{cm}^2$ after 10 days of storage, respectively, on aerobic plate counts.

• Korean journal of food and cookery science
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• v.17 no.6
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• pp.565-570
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• 2001

Soibirhym(Portulace oleracea) was extracted by methanol and its antimicrobial activities against food spoilage or foodborne disease microorganisms were investigated by the paper disc method. The microorganisms used in this experiment included 5 species of bacteria(Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Klebsiella Pneumoniae, Staphylococcus aureus) and 3 species of fungi(Fusarium solani, Aspergillus flavius, Penicillium citreonigrum). Soibirhym showed high antimicrobial activites against P. citreonigrum, P. aeruginosa and K. pneumoniae. Minimum inhibitory concentrations(MICs) on S. aureus, P. citreonigrum and K. pneumoniae were 200, 200 and 250 mg/㎖, respectively. In the methanol extracts from Soibirhym, 147 kinds of compound were separated by GC/MS. The extraction yields of phenolics, furans, alcohols, acids and esters, ketones, aldehydes, and miscellaneous compounds were 7.43%, 6.13%, 2.20%, 41.06%, 9.21%, 0.15% and 1.08%, respectively. Some antimicrobial compounds such as 2,3-dihydro-benzofuran, 4-hydroxy-3-methoxy-benzoic acid, 4-hydroxy benzeneethanol were detected in the methanol extract.