• Journal of Microbiology
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• 제42권3호
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• pp.188-193
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• 2004

Xanthobacter flavus strain UE15 was isolated in wastewater obtained from the Ulsan industrial complex, Korea. This strain functions as a 1,2-dichloroethane (1,2-DCA) degrader, via a mechanism of hydrolytic dechlorination, under aerobic conditions. The UE15 strain was also capable of dechlorinating other chloroaliphatics such as 2-chloroacetic acid and 2-chloropropionic acid. The dhlA gene encoding 1,2-DCA dechlorinase was cloned from the genomic DNA of the UE15 strain, and its nucleotide sequence was determined to consist of 933 base pairs. The deduced amino acid sequence of the DhlA dechlorinase exhibited 100％ homology with the corresponding enzyme from X. autotrophicus GJ10, but only 27 to 29％ homology with the corresponding enzymes from Rhodococcus rhodochrous, Pseudomonas pavonaceae, and Mycobacterium sp. strain GP1, which all dechlorinate haloalkane compounds. The UE15 strain has an ORF1 (1,356 bp) downstream from the dhlA gene. The OFR1 shows 99％ amino acid sequence homology with the transposase reported from X. autotrophicus GJ10. The transposase gene was not found in the vicinity of the dhlA in the GJ10 strain, but rather beside the dhlB gene coding for haloacid dechlorinase. The dhlA and dhlB genes were confirmed to be located at separate chromosomal loci in the Xanthobacter flavus UE15 strain as well as in X. autotrophicus GJ10. The dhlA and transposase the UE15 strain were found to be parenthesized by a pair of insertion sequences, 181247, which were also found on both sides of the transposase gene in the GJ10 strain. This unique structure of the dhlA gene organization in X. flavus strain UE15 suggested that the dechlorinase gene, dhlA, is transferred with the help of the transposase gene.

• 한국수산과학회지
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• 제39권6호
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• pp.431-436
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• 2006

This study was red snow crab Chionoecetes japonicus cooker effluent (RSCCE) for making a natural crab-like flavorant. The RSCCE ($1\;^{\circ}Brix$ in the initial state) was concentrated up to $40^{\circ}Brix$ to determine the optimal conditions for making a natural flavorant. During concentration, the amino-N content and total acidity increased with the concentration time, while the pH was maintained in range 7.94-8.78. In the acceptance test and quantitative description analysis (QDA), $20^{\circ}Brix$ RSCCE had the best quality in terms of taste (5.87), odor (6.00), and overall acceptance (5.80). Of the taste compounds analyzed in $20^{\circ}Brix$ RSCCE, lactic acid was an abundant non-volatile organic acid, and the nucleotide 5'-inosine monophosphate (IMP) was present, as were four free amino acids: tyrosine, glutamic acid, alanine and glycine. The taste and odor of boiled crabmeat were retained in $20^{\circ}Brix$ RSCCE based on the QDA.

• 한국축산식품학회지
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• 제35권3호
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• pp.406-412
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• 2015

The combined effects of electron-beam irradiation and ageing of beef were examined. The irradiated samples at dose of 0 or 2 kGy were kept and analyzed for the microbial growth, shear values, meat color, and nucleotide-related flavor compounds at different ageing temperatures (2, 10, or 25℃) for 8 d. The irradiation effect on inactivation of foodborne pathogens was also investigated. The population of Listeria monocytogenes and E. coli O157:H7 inoculated in beef samples decreased in proportion to the irradiation dose, showing D₁₀ values of 0.66 and 0.65 kGy respectively. The irradiated beef eye of round had lower number of total aerobic bacteria (TAB) than nonirradiated one during the storage, but the TAB increased with higher ageing temperature (p<0.05). Especially, TAB increased sharply in non-irradiated samples aged at 25℃ after 4 d (p<0.05). With increasing ageing temperature and ageing time, shear force values decreased (p<0.05). The color a* values of the irradiated beef were lower than those of the non-irradiated throughout the ageing period (p<0.05). As ageing time and temperature increased, the amounts of inosine monophosphate decreased and the hypoxanthine increased (p<0.05). Relatively high ageing temperature could be used at irradiated beef eye of round to shorten the ageing time.

• 한국식품영양학회지
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• 제13권6호
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• pp.521-528
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• 2000

분말 다시마로부터 정미성분의 효과적인 추출방법과 분말 조미료의 제조 조건을 검토한 결과를 요약하면 다음과 같다. 다시마에 함유된 정미성분의 추출은 열수 추출이나 효소분해 법보다 70% ethyl alcohol 처리가 효과적이었으며, 분말제품의 수율을 높이기 위해서는 잔사를 다시 열수 추출시키는 것이 효과적이었다. 다시마 분말에 70% ethyl alcohol을 5배량 가하여 $25^{\circ}C$에서 1시간 추출하고 여과한 잔사에 다시 물을 15배 가하여 7$0^{\circ}C$에서 3시간 동안 추출하였을 때 고형물의 농도는 14.9%였다. 다시마 분말조미료는 ethyl alcohol 추출액을 막으로 통과시켜 분자량 5,000 dal-ton이하 범위로 분획한 액을 진공동결건조하여 제품으로 하였다. 다시마 분말조미료 제품의 조성 중 탄수화물 함량이 64.9%로 가장 높게 나타났고, 총질소량 및 아미노질소량은 3.7% 및 2.1%로 나타나 총질소량에 대한 아미노질소량의 비율은 56.8%이었다. 그리고 상대습도 0.88에서의 흡습성은 8.4%, 용해성은 98.3%, 건조수율은 14.7%였다.

• Asian-Australasian Journal of Animal Sciences
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• 제31권1호
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• pp.123-128
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• 2018

Objective: This study was performed to determine effects of different curing salts on the quality of salamis and to assess feasibility of using NaCl-alternative salts. Methods: Various types of curing salts (KCl or $MgCl_2$) as well as NaCl (sun-dried or refined) were incorporated for processing of salamis. The proximate composition, fatty acids, nucleotide-related compounds, and free amino acids of the salamis were analyzed during 40 days of ripening. Results: The substitution of NaCl by KCl caused higher fat and ash content, but lower moisture content of the salami after 20 days of ripening (p<0.05). Compared with the sun-dried NaCl, use of KCl in salami also led to greater inosine 5'-monophosphate whereas refined NaCl had more inosine (p<0.05). KCl-added salami also had a higher C12:0, C17:1, and C20:0 than other types of salami (p<0.05). $MgCl_2-added$ salami had higher content of free amino acids compared to the other salamis (p<0.05). Conclusion: Alternative curing salts such as KCl and $MgCl_2$ could substitute NaCl in consideration of quality factor of a fermented meat product. Especially replacement of NaCl with KCl will be a suitable strategy for developing relatively low sodium salami products without compromising product quality.

• 한국축산식품학회지
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• 제40권6호
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• pp.946-956
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• 2020

To identify the effect of sodium-alternative curing salts on the quality properties of salami through the ripening process, four salami treatments were prepared with different curing salts, T1 (-control, NaCl 1.9%), T2 (+control, NaCl 1.9%+NaNO₂ 0.01%), T3 (KCl 1.9%+NaNO₂ 0.01%), and T4 (MgCl₂ 1.9%+NaNO₂ 0.01%), under 40 days ripening conditions. Sodium-alternative salts (T3 or T4) showed characteristically different quality traits compared with T2. Especially, T3 had lower pH, water activity, volatile basic nitrogen, and lipid oxidation after 20 days of ripening period, compare with T2 or T4 (p<0.05). Sodium nitrite had critical impact on increased a* values, and T3 showed higher a* values compared with T2 or T4 (p<0.05). Sodium nitrite reduced initial growth of coliforms but sodium-alternative salts did not affect microbial growth patterns. T2-T4 containing sodium nitrite had higher content of umami nucleotide flavor compounds compared with T1, regardless of the chlorine salt species. The combined use of sodium-alternative curing salts and minimal sodium nitrite was found to be an applicable strategy on development of low sodium salami without a trade-off of the product quality.

• 한국축산식품학회지
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• 제36권2호
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• pp.215-222
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• 2016

The combined effects of irradiation and aging temperature on the microbial and chemical quality of beef loin were investigated. The samples were vacuum-packaged, irradiated at 0 or 2 kGy using electron-beam (EB), and stored for 10 d at different aging temperatures (2, 14, or 25℃). The microbial growth, shear values, meat color, and nucleotide-related flavor compounds of the samples were analyzed. The irradiation effect on inactivation of foodborne pathogens was also investigated. The population of Listeria monocytogenes and Escherhia coli O157:H7 inoculated in beef samples decreased in proportion to the irradiation dose. Irradiation reduced the total aerobic bacteria (TAB) over the storage, but higher aging temperature increased the TBA. Thus TAB increased sharply in non-irradiated and high temperature-aged (14, 25℃) beef samples after 5 d. With increasing aging temperature and aging time, shear force values decreased. Lipid oxidation could be reduced by short aging time at low aging temperature. The color a* values of the irradiated beef were lower than those of the non-irradiated throughout the aging period. As aging period and temperature increased, IMP decreased and hypoxanthine increased. Considering microbial and physicochemical properties, irradiation can be used for raw beef to be aged at relatively high temperature to shorten aging time and cost.

• 한국식품영양과학회지
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• 제30권6호
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• pp.1142-1146
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• 2001

멸치액젓의 속성발효기술개발의 일환으로 무화과의 단백질 분해효소를 이용하여 멸치 액젓 제조기술을 개발하고자 미숙 무화과, 숙성 무화과 및 무화과 잎을 3% 첨가하여 $25^{\circ}C$에서 60일 동안 발효시킨 후 액젓의 품질 특성을 분석하였다. 단백질 분해효소 활성은 숙성 무화과가 산성 protease 1,327 units, 중성 protease 535 units, 알칼리 protease 2,833 units로 가장 높았다. 60일 동안 발효시킨 후 액젓의 색은 숙성 무화과를 이용하여 발효시켰을 때 a값이 0.48, b값 -0.43, L값 27.26으로 가장 우수한 적자색을 보였다. 무화과를 첨가한 멸치액젓의 발효과정 중 아미노태 질소 함량은 발효초기 10일 째 식품공전상의 규격기준인 600 mg%에 도달하였으며, 숙성과가 가장 빠른 증가율을 보였다. 발효 60일째 시험구에 따라 다소 차이는 있었으나 1500 mg%에 달하였다. 총 유리 아미노산은 숙성 무화과가 4543.21 mg%로 대조구의 2255.29 mg%에 비하여 약 2배정도 높은 함량을 보였으며, 중요 핵산 관련물질은 주로 hypoxanthin이었다. 액젓 제조시 미숙과와 무화과 잎을 사용하였을 때 chlorophyll 색소가 추출되어 제품이 녹색을 나타내는 문제와 약간의 풋냄새 등을 고려할 때 숙성과가 적합함을 알 수 있었다.

• Genomics & Informatics
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• 제7권4호
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• pp.187-194
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• 2009

Cytochrome P450 2E1 (CYP2E1) is a member of the cytochrome P450 superfamily, and it is a key enzyme responsible for the metabolic activation of many smallmolecular-weight compounds such as alcohol, which is classified as a human carcinogen. In this study, we identified 19 single nucleotide polymorphisms (SNPs) in CYP2E1 in Korean population. In these SNPs, we examined possible genetic association of CYP2E1 polymorphisms with HBV clearance and the risk of hepatocellular carcinoma (HCC). Five common polymorphic sites were selected, CYP2E1 polymorphisms at rs381-3867, rs3813870, rs2070673, rs2515641 and rs2480257, considering their allele frequencies, haplotype-tagging status and LDs for genotyping in larger-scale subjects (n=1,092). Statistical analysis demonstrated that CYP2E1 polymorphisms and haplotypes show no significant association with HBV clearance, HCC occurrence and onset age of HCC (p>0.05). Previous studies, however, have shown contradictory findings on associations of CYP2E1 polymorphisms with CYP2E1 activities and HCC risk. Comparing the contrasting results of previous researches suggest that CYP2E1 polymorphism is associated with CYP2E1 activity induced by ethanol, but is not directly associated with HCC risk. CYP2E1 variation/haploype information identified in this study will provide valuable information for future studies on CYP2E1.

• Journal of Microbiology and Biotechnology
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• 제29권8호
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• pp.1212-1220
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• 2019

The study of metabolomics in natural products using the diverse analytical instruments including GC-MS, LC-MS, and NMR is useful for the exploration of physiological and biological effects and the investigation of drug discovery and health functional foods. Cordyceps militaris has been very attractive to natural medicine as a traditional Chinese medicine, due to its various bioactive properties including anti-cancer and anti-oxidant effects. In this study, we analyzed the metabolite profile in 50% ethanol extracts of C. militaris fruit bodies from three development periods (growth period, matured period, and aging period) using $^1H-NMR$, and identified 44 metabolites, which are classified as 16 amino acids, 10 organic acids, 5 carbohydrates, 3 nucleotide derivatives, and 10 other compounds. Among the three development periods of the C. militaris fruit body, the aging period showed significantly higher levels of metabolites including cordycepin, mannitol (cordycepic acid), and ${\beta}-glucan$. Interestingly, these bioactive metabolites are positively correlated with antitumor growth effect; the extract of the aging period showed significant inhibition of HepG2 hepatic cancer cell proliferation. These results showed that the aging period during the development of C. militaris fruit bodies was more highly enriched with bioactive metabolites that are associated with cancer cell growth inhibition.