• 한국환경성돌연변이발암원학회지
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• 제25권1호
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• pp.6-12
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• 2005

Many compounds might become activated after absorption of UV light energy. In some cases, the resulting molecule may undergo further biological reaction of toxicological relevance related especially to the photo-carcinogenicity resulting from photo-genotoxicity. However, no regulatory requirements have been issued with the exception of guideline issued by the Scientific Committee of Cosmetology, Commission of the European Communities (SCC/EEC) on the testing of sunscreens for their photo-genotoxicity. Thus, the objectives of this study are to investigate the utility of photo-Ames assay for detecting photo-mutagens, and to evaluate its ability to predict rodent photo-carcinogenicity. Photo-Ames assay was performed on five test substances that demonstrated positive results in photo-carcinogenicity tests: 8-methoxypsoralen (photoactive substance that forms DNA adducts in the presence of ultraviolet A irradiation), chlorpromazine (an aliphatic phenothiazine an a-adr-energic blocking agent), lomefloxacin (an antibiotic in a class of drugs called fluoroquinolones), anthracene (a tricyclic aromatic hydrocarbon a basic substance for production of anthraquinone, dyes, pigments, insecticides, wood preservatives and coating materials) and retinoic acid (a retinoid compound closely related to vitamin A). Out of 5 test substances, 3 showed a positive outcome in photo-Ames assay. With this limited data set, an investigation into the predictive value of this photo-Ames test for determining the photo-carcinogenicity showed that photo-Ames assay has relatively low sensitivity (the ability of a test to predict carcinogenicity). Thus, to determine the use of in vitro genotoxicity tests for prediction of carcinogenicity,' several standard photo-genotoxicity assays should be compared for their suitability in detecting photo-genotoxic compounds.

• 한국식품과학회지
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• 제29권6호
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• pp.1275-1280
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• 1997

차엽카테킨을 김치 천연보존제로서의 이용가능성을 검토하기 위하여 차엽에서 분말형태로 차엽카테킨을 조제하였다. 이 차엽카테킨을 김치산패에 관여하는 미생물인 St. feacalis, Leuc. mesenteroides, L. plantarum, L. brevis, P. cerevisiae와 Sachh. cerevisiae를 대상으로 항미생물 활성을 검정한 결과, Leuc. mesenteroides, L. plantarum, P. cerevisiae에 대해서는 2 mg/mL 첨가수준, St. faecalis는 4 mg/mL 첨가수준, L. brevis는 5 mg/mL 첨가수준에서부터 균의 생육이 억제되기 시작하였으나 Sacch. cerevisiae에 대한 생육억제효과는 낮았다. 차엽카테킨을 배추김치와 물김치에 첨가시기와 첨가수준을 달리하여 첨가하여 숙성중의 pH 및 산도의 변화를 측정한 결과, 두종의 김치 모두 2 mg/g 첨가수준 이상에서 pH저하와 산도증가가 억제되어, 김치의 천연보존제 및 산패억제제로서 차엽카테킨의 이용가능성이 시사되었다.

• Journal of Applied Biological Chemistry
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• 제57권2호
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• pp.123-129
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• 2014

The antioxidant and antimicrobial activities of Camellia oleifera seed oil were studied. Four kinds of seed oil samples were prepared, crude oil and refined oil, extracted by cold pressing method (CPC, CPR), and organic solvent extraction (OSC, OSR). Antioxidant activity analysis was measured in 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid)-diammonium salt, ferric reducing Ability of Plasma, and 2,2-diphenyl-1-picrylhydrazyl assays. Besides, the percentage of inhibition of red blood cells hemolysis induced by 2,2'-azobis(2-amidnopropane) dihydrochlorid, the lag time of LDL conjugated dienes formation in vitro, and the inhibitors of loss in tryptophan fluorescence were all used to estimate the antioxidant activity of the samples. The total phenolic contents (TPC) were detemined by Folin-Ciocalteu method. The TPC of the C. oleifera seed oils can be arranged in descending order: CPC ($1.9172{\mu}g/mL$) > OSC ($1.5218{\mu}g/mL$) > CPR ($1.0611{\mu}g/mL$) > OSR ($0.6782{\mu}g/mL$). And the oils were investigated for activity against Escherichia coli, Bacillus subtilis, Saccharomyces cerevisiae and Aspergillus niger. The results showed the antioxidant activity of crude oil by cold pressing method was stronger than others, and all oils did inhibit activity of the top three bacteria expert A. niger. The further significance of the study contributes to measure the antioxidant and antimicrobial activity of the potential health benefits by the different methods of preparation and the oil of C. oleifera seeds acting as free radical scavenger, pharmaceuticals and preservatives may offer some information in medicine and cosmetic not just in food field.

• 한국식품조리과학회지
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• 제19권3호
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• pp.300-307
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• 2003

This research investigated the consumption of various rice-based processed foods of 279 housewives in Daegu. 70% of the housewives that responded to the question graduated from a high school or college, was 30∼40 years old and full-time housewives. The main places for purchasing the rice-based processed foods were large size discount store and supermarkets, as other industrial products and the family′s preference was the most critical factors in choosing the products. The fact that the main reason of purchasing the rice breads and cookies, instead of wheat, was "They may be good for health” indicated many housewives have a positive perception of rice-based foods. Among the rice-based processed foods, the using frequency of rice cake (dduk) was the highest, with rice cookies and rice drinks being the next most frequent. However, the frequencies of cooked rice (bob) and rice flour were very low. An analysis of the correlation for the using frequency of 15 rice-based processed foods showed that the use of rice cookies and breads, instead of wheat, was highly correlated to another 13 foods. The critical reasons why they do not consume cooked rice and rice flour were uncertainty of the purity of the rice and the addition of preservatives, and that with rice bread and noodles there was no information available about the products, and hey have a poor taste. The most common reasons of using cooked rice were no time to cook and simple curiosity about the products. However, the consumers were suspicious of containers, which were a potential cause of environmental hormones, and the high price of the products. Packed rice flour was mainly used as an ingredient to give the viscosity to a product. The advantages of using rice flour were that it was available to control the amount of buying and the convenience to buy. However, it was pointed out that the taste of products containing packed rice flour were poorer than that of rice flour ground at a mill.

• 한국식품영양과학회지
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• 제29권5호
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• pp.814-821
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• 2000

나박김치의 저장성 향상을 위한 천연보존제로서 이용 가능성을 검토하기 위해 오미자 물추출물을 제조하여 이들 시료의 농도를 0.5, 1.0, 1.5, 2.0%로 사용하여 항산화력 및 전자공여능을 측정하고 나박김치 발효에 관여하는 젖산균에 대해 항균활성을 조사하였다. 항산호력은 TBA값을 측정하였는데, 오미자 물추출물의 농도가 높을수록 항산화 효과가 뚜렷이 나타났고, 시간이 경과할수록 그 효과는 현저하였다. 전자공여능 또한 오미자 물추출물의 농도가 높을수록 높은 전자공여능을 나타냈고, 1.0% 이상이 높은 전자공여능을 보였다. 나박김치에서 잦산균을 분리한 결과 117균주를 1차 분리하였고, 이 가운데 성장이 우수하고 산 생성력이 강한 4균주를 2차 선별하여 Lactobacillus brevis, Lactococcus faecalis, Leuconostoc mesenteroides, Lactobacillus plantarum을 확인하였다. 이들의 항균활성을 측정한 결과 Lactobacillus brevis를 제외한 세 균주 모두 오미자 물추출물 첨가에 의한 뚜렷한 성장 억제현상을 나타내었다. 따라서 나막김치 담금시에 항산화성과 항균활성이 있는 오미자 물추출물을 이용할 수 있는 가능성이 높을 것으로 생각되었다.

• 대한금속재료학회지
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• 제48권11호
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• pp.1035-1040
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• 2010

The research efforts on GaN-based light-emitting diodes (LEDs) keep increasing due to their significant impact on the illumination industry. Surface mount technology (SMT) is widely used to mount the LED packages for practical application. In surface mount soldering both the device body and leads are intentionally heated by a reflow process. We studied on the effects of multiple reflows on microstructural variation and joint strength of the solder joints between the LED package and the substrate. In this study, Pb-free Sn-3.0Ag-0.5Cu solder and a finished pad with organic solderability preservatives (OSP) were employed. A $Cu_6Sn_5$ intermetallic compound (IMC) layer was formed during the multiple reflows, and the thickness of the IMC layerincreased with an increasing number of reflows. The shear force decreased after three reflows. From the observation of the fracture surface after a shear test, partially brittle fractures were observed after five reflows.

• 한국축산식품학회지
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• 제41권6호
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• pp.1060-1077
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• 2021

Food additives are required to maintain the freshness and quality of foods, particularly meats. However, chemical additives may not be preferred by consumers, and natural materials with antimicrobial and antioxidant effects may be used as replacements for common chemical additives. Accordingly, in this study, we compared the antimicrobial and antioxidant activities of natural compounds extracted with ethanol and hot water, and emulsion sausage prepared with natural ethanol extracts was analyzed for pH, color, thiobarbituric acid reactive substances (TBARS), and Clostridium perfringens growth during storage. The antimicrobial activities of 49 natural extract candidates against Listeria monocytogenes, C. perfringens, Salmonella spp., and Escherichia coli were analyzed, and six natural materials with excellent antibacterial activities, i.e., Elaeagnus umbellata Thunb. f. nakaiana (Araki) H. Ohba, Punica granatum L., Ecklonia cava, Nelumbo nucifera Gaertner, and Schisandra chinensis (Turcz.) Baill., and Rubus coreanus Miq. were evaluated to determine their total polyphenol contents and DPPH radical scavenging activities. The total polyphenol contents of ethanol extracts were higher than those of hot water extracts, whereas DPPH radical scavenging activity was found to be higher in hot water extracts. The TBARS values of emulsion sausages were significantly increased as storage time increased, and the TBARS values of emulsion sausages prepared with natural extracts were lower than those of control sausages. Natural extract-treated emulsion sausages showed a 99% reduction in bacterial contents compared with untreated sausages on day 2, with greater than 99.9% reduction after day 3. Thus, these results demonstrated that natural extracts could have applications as natural preservatives in meat products.

• Animal Bioscience
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• 제34권9호
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• pp.1479-1490
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• 2021

Objective: Our recent findings confirmed the effectiveness of sodium metabisulfite (SMB) in controlling the growth of undesirable microorganisms in fruit and vegetable discards (FVD); however, lactic acid bacteria (LAB) are susceptible to its antibacterial effects. Two series of experiments were conducted to enable the survivability of LAB during silage fermentation of a total mixed ration (TMR) containing SMB-treated FVD. Methods: In Exp. 1, the objective was to isolate a strain of LAB tolerable to the toxic effect of SMB. In Exp. 2, the SMB load was minimized through its partial replacement with a chemical mixture (CM) based on sodium benzoate (57%), potassium sorbate (29%), and sodium nitrite (14%). FVD was treated with SMB + CM (2 g each/kg biomass) and added to the TMR at varying levels (0%, 10%, or 20%), with or without KU18 inoculation. Results: The KU18 was screened as a presumptive LAB strain showing superior tolerance to SMB in broth medium, and was identified at the molecular level using 16S rRNA gene sequence analysis as Lactobacillus plantarum. Inoculation of KU18 in TMR containing SMB was not successful for the LAB development, biomass acidification, and organoleptic properties of the resultant silage. In Exp. 2, based on the effectiveness and economic considerations, an equal proportion of SMB and CM (2 g each/kg FVD) was selected as the optimal loads for the subsequent silage fermentation experiment. Slight differences were determined in LAB development, biomass acidification, and sensorial characteristics among the experimental silages, suggesting the low toxicity of the preservatives on LAB growth. Conclusion: Although KU18 strain was not able to efficiently develop in silage mass containing SMB-treated FVD, the partial substitution of SMB load with the CM effectively alleviated the toxic effect of SMB and allowed LAB development during the fermentation of SMB + CM-treated FVD in TMR.

• 한국미생물·생명공학회지
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• 제49권2호
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• pp.131-137
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• 2021

This study aimed at isolating lactic acid bacteria with anti-MRSA (methicillin-resistant Staphylococcus aureus) bacteriocin activity from fermented shrimp. We selected three strains, named Weissella sp. S1, S2, and S3, using analysis based on 16S rRNA gene sequences. All strains showed appropriate growth in an MRS medium containing 5% (w/v) NaCl and showed antibacterial activities against Bacillus cereus, Escherichia coli, Staphylococcus aureus, and MRSA. The strains exhibited similar growth rates at 0-5% NaCl, with approximate reduction in growth rate observed at 9% NaCl. Weissella sp. S1, S2, and S3 exhibited maximum growth rates at pH 7, 9, and 8, respectively. The crude bacteriocin was prepared from Weissella sp. S3 and subjected to characterization. The remaining activities after 30 min of exposure at each temperature were 100%, beyond 75%, and 49% at 4℃ and 37℃, 50℃ and 70℃, and 100℃, respectively. The remaining activities after 24 h of exposure at each pH were 100%, 75%, and 49% at pH 3 and 5, 7 and 9, and 10, respectively. Use of 50% (v/v) ethanol or isopropanol treatment did not diminish the antibacterial activity of the bacteriocin, while the 50% (v/v) hexane treatment reduced the activity by 51%. The molecular weight of the bacteriocin was nearly 6 kDa that was quantified using tricine-SDS-PAGE. Our findings suggest that Weissella sp. S3 may be considered a probiotic and useful source of antimicrobial substances in the development of bio-preservatives for food or in MRSA treatment.

• 한국환경보건학회지
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• 제47권6호
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• pp.513-520
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• 2021

Background: Benzalkonium chloride (BKC) has been extensively used as a preservative in industrial products and in hygiene, medical, and cosmetic applications. Humidifier disinfectant (HD) products containing BKC have been used in South Korea. Objectives: This study was aimed to review types of products containing BKC, to summarize the regulations in the US, EU, Japan, and South Korea, and to review the health effects associated with the use of HD. Methods: We reviewed and summarized documents which were searched through PubMed and Google Scholar with the key words: BKC and asthma/contact dermatitis, humidifier disinfectant-associated lung injury (HDLI), and more. Results: Regulations in most countries including South Korea do not allow its use as disinfectants in spray-type of products for medicine, cosmetics, and household products. Two types of HD containing BKC (800~1,270 ppm) were marketed in South Korea from 1996~2003. Health effects reported from people who used products containing BKC were allergic contact dermatitis, erythema, and respiratory disease, including asthma. Two people who responded as HD users containing BKC only were confirmed to have developed asthma. HD-associated lung injury (HDLI) was reported by consumers who used both HD containing polyhexamethylene guanidine (PHMG) and HD containing BKC. Conclusions: In conclusion, the use of BKC as a biocide has to be controlled considering the route and pattern of exposure. Products containing BKC as preservatives were reviewed with exposure routes and sites in the human body such as skin, eyes, and the respiratory tract. HD containing BKC was clinically evaluated to be associated with asthma.