• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2000.04a
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• pp.12-13
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• 2000

최근 플라스틱제 식품 포장재에 대한 환경학적 문제가 제기됨으로 인하여 다양한 곡류 단백질의 필름 형성능력에 많은 관심이 모아지고 있다. 단백질 필름으로서 soy protein, wheat gluten, rice bran, corn zein, glatin 및 colloagen 등의 소재들이 많은 관심을 모으고 있으며, 비교적 필름 형성력이 뛰어나고, 저렴한 가격으로 구입할 수 있는 대두 단백질에 커다란 관심이 모아지고 있는 실정이다. 이들 물질로부터 제조된 가식성 필름 및 코팅제들은 식품의 보존기간을 연장시킬 뿐만 아니라 수분 및 용질의 이동을 방지하여 식품의 품질을 개선시킬 수 있다. 또한 이들 필름 및 코팅제들은 산소 및 이산화탄소의 이동, 이로 인한 지방 산화 그리고 휘발성 향기성분들의 감소 등을 조절할 수 있다. 대두 단백질 필름의 사과 코팅제로서의 이용은 개별적 포장이 용이하지 않는 제품들의 코팅제로서 활용하여 대두 단백질 필름 및 코팅제의 잠재적 시장성을 확인하는 하나의 응용분야이다. 본 실험의 목적은 대두 단백질 코팅제를 후지와 golden delicious 사과에 코팅하여 상온 (22$^{\circ}C$)과 냉장온도(2-4$^{\circ}C$)에서 60일동안 보관하여 색도, 경도 및 산도 변화 등을 측정하여 저장 중 사과의 품질에 미치는 영향을 조사하였다. 대두 단백질 코팅제는 대두 단백 용액들 (5g, 8g, 10g/100mL water)에 glycerin (50% w/w의 단백질)을 가소재로 첨가한 후 알칼리 용액으로 pH 9.0에 맞추었다. 그런후 85$^{\circ}C$에서 30분간 가열하여 코팅제를 준비하였다. 후지 사과(붉은색)와 golden delicious 사과 (초록색)를 dipping 방법으로 코팅하여 60일도안 실온과 냉장온도에 저자하여 보존기간의 연장을 확인하였다. 사과품질의 결정인자는 Hunter L, a, b 색도값과 사과의 조직의 강도 (외부 및 내부) 그리고 산도 등을 측정하였다. 코팅된 후지 및 golden delicious 사과의 표피 및 내부 경도는 control과 비교하여 높은 경도를 유지하였다. 또한 냉장온도에서 30일 동안 보관하였을 때, control 사과와 거의 비슷한 경도를 유지하였다. 식품의 색도를 소비자의 기호를 결정하는 중요한 인자이다. 대두 단백질로 코팅된 후지 사과는 상온에서 20일 동안은 control에 비하여 약간의 색도의 증가를 보였으나, 그 후 60일 동안은 색도의 증가를 보이지 않았다. 그러나 냉장 보관한 control 후지 사과에 비하여 색도의 증가가 관찰되었다. 대두 단백질 코팅제가 사과의 색도 변화를 방지하는 효과를 가졌으나, 저장 온도가 색도의 변화에 더욱 큰 영향을 미침을 알 수 있었다. 대두 단백질로 코팅된 golden delicious는 상온에서60일 동안 보관하였을 경우, 사과표피의 색도 변화를 현저히 지연시킴을 확인하였다. 또한 control과 비교하여 성공적으로 사과에 코팅하였으며, 상온에서 보관하여을 때 사과의 품질을 30일 이상 연장하는 효과를 관찰하였다. 이들 결과로부터 대두단백질 필름이 과일 등의 포장제로서 이용할 가능성을 확인하였다.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2000.04a
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• pp.14-15
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• 2000

현재의 농업에서 농약의 사용은 불가결한 것이다. DDT의 등장으로 농약만능시대의 막이 열린 이래 세계에서 10만종 이사의 농약이 탄생했다. 현재 전세계의 생산량은 매년 1천만 톤을 넘어섰고 일본의 경우 등록되어 있는 농약수는 원체(화합물종류)로서 367종, 상품명으로서는 약 5800 종류가 판매되고 있다. 년간 일본의 농약생산량은 약 60만 톤으로 농약의 수출량과 수입량이 거의 같기 때문에 생산량이 사용량에 상당하는 것으로 본다. 농약의 식품오염의 측면에서 보면, 단위 면적당 세계 제 1위의 농약 사용국인 일본은 시장에 유통되고 있는 농작물에도 상당한 양의 농약이 잔류하는 것으로 본다. 물론 식품위생법에 26종의 농약에 대해 53작물을 대상으로 하는 잔류농약기준이 있지만, 농약성분이 400종 이상이며 산포 대상이 되는 작물은 53작물보다 훨씬 많다. 또한 한 두 종류의 작물밖에 대상이 되지 않는 농약도 많아서 잔류농약기준은 식품의 안전성 확보면에서는 부족한 것이 많아. 따라서 농산물 생산자 스스로가 농약사용기준을 정확하게 지켜주기를 바랄 뿐이다. 한편으로는, 이러한 현실에 비추어서 농약사용이 일상화된 농업자에게 있어 농약으로 인한 건강상의 문제 또한 적지 않다. 농업자의 건강관리 대책의 일환으로 실시하는 건강진단 및 조사에 따르면, 만성적인 질환뿐만 아니라 농약산포작업후에 나타나는 증세(기침, 피부이상, 불쾌감, 두통, 인후염, 구토)를 경험한 작업자는 예방의학적인 견지에서 농업자의 농약폭로실태파악 및 교육을 해오고 있으나 그다지 설득력을 얻지 못하여 보다 확실한 인체내 흡수량을 측정하는 방법을 생각하게 되었다. 즉 뇨중 농약 대사물을 폭로지표로 하는 생물학적 모니터링(biological monitoring)을 시도, 농업현장에 있어서의 그 실증과 유용성에 대한 검토를 하고자 하였다. 농작업 가운데서 가장 위험하다고 보는 농약산포작업 (수동식 분무기를 이용한 하우스작물 및 동력분무기를 사용한 노지작물)을 대상으로 생물학적모니터링을 실시한 결과 업자의 뇨로부터 농약의 체내흡수를 반영하는 농략의 뇨 분비성 대사물을 측정할 수 있었다. 즉 뇨나 혈액등의 생체시료를 이용한 생물학적모니터링의 농약에의 응용은 서구와는 달리 대부분이 규제가 없는 소규모 자가영농으로 정해진 농약사용지침보다 많은 농약을 사용한다거나, 또는 개인의 습관이나 작업환경에 따라 폭로조건이 달라서 실질적인 폭로-흡수의 정도가 불분명한 경우등에도 충분히 대응할 수 있어 농약사용자 개개인의 농약 폭로-흡수의 정도를 분명하게 밝힐 수 있다. 게다가 평가의 결과를 농약사용의 일선에 있는 농업자에게 피드백 하여 주므로서 농약에 대한 인식을 새롭게 하고 농약취급시의 건강장해예방행동을 촉구하는 등의 효과도 높은 것으로 예방의학적인 유용성이 크다고 볼 수 있다.

• Journal of Life Science
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• v.18 no.1
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• pp.52-57
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• 2008

Xylan is a major hemicellulose component of the cell walls of monocots and hardwood, representing up to 30% of the dry weight of these plants. To efficiently hydrolyze xylan, the endoxylanase gene from Bacillus sp. was expressed in B. subtilis DB431 by introducing the plasmid pJHKJ4. The total activity of the recombinant endoxylanase reached about 857 unit/ml by batch fermentation of B. subtilis DB431/pJHKJ4 in LB maltose medium. The majority (>92%) of endoxylanase was efficiently secreted into the culture medium. The recombinant endoxylanase hydrolyzed more the birchwood xylan efficiently than the other xylans. When 4 % concentration of xylan was used, the highest production of xylooligosaccharide was observed, and xylobiose and xylotriose were the major products. Optimal amount of enzyme and reaction time for producing xylooligosaccharide were found to be 10 unit and 1 hr, respectively. In addition, the temperature of $40^{\circ}C{\sim}50^{\circ}C$ gave the highest production of xylooligosaccharide. Consequently, the optimized conditions for the production of xylooligosaccharide through the hydrolysis of xylan were determined as follows: 10 unit endoxylanase, $50^{\circ}C$, 4% birchwood xylan, 1 hr reaction.

• Journal of Life Science
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• v.20 no.3
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• pp.356-364
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• 2010

This study was carried out to investigate the exposure pathway of PBDEs in human breast milk collected from new mothers residing in Chuncheon, a comparatively clean area in Korea. The congeners of PBDE in 22 human breast milk samples were analyzed using a high resolution gas chromatography with a high resolution mass detector. The residue level of ${\sum}PBDEs$ was higher in primipara subjects than in multipara subjects (p<0.05). The levels in this study were similar to those of people in some Asian and European countries, but were lower than those of people in north America. In the congener profiles, BDE-47 (mean contribution=36.1%) was predominant, followed by BDE-153 (27%), BDE-99 (11.7%), BDE-100 (11.1%), BDE-28 (7.9%) and BDE-183 (3.5%). The sum of BDE-47 and BDE-153 accounted for more than 50% of ${\sum}PBDEs$ in most samples. BDE-47 was highly correlated with ${\sum}PBDEs$ (r=0.94, p<0.001). No strong trend was observed between PBDE levels and a number of key biological factors (women's age, weight, height and body mass index) examined in this study, however, weak correlations were observed in PBDE levels measured against dietary habits, particularly in fish consumption frequency. It seems that Korean people might be exposed to multiple sources including products of PBDEs, and particularly food resources.

• Journal of Life Science
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• v.23 no.7
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• pp.933-940
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• 2013

The aim of this work was to determine the chemical composition of essential oil from aerial partsof Mentha arvensis L. f. piperascens (MAO) and to evaluate the effect of its fragrant chemicals on electroencephalographic (EEG) activity of human brain. The MAO was obtained by supercritical $CO_2$ extraction. The maximum yield was 2.38% at conditions of $70^{\circ}C$ and 200 bar. There were 32 volatile chemicals with 6 alcohols (67.11%), 13 hydrocarbons (17.05%), 9 esters (11.50%), 2 ketones (7.16%), 1 oxide (2.77%), and 1 aldehyde (0.56%). The major components were (Z,Z,Z)-9,12,15-octadecatrien-1-ol (50.06%), 2-hydroxy-4-methoxyacetophenone (7.50%), and 3,4-dihydro-8-hydroxy-3-methyl-1H-2-benzopyran-1-one (6.60%). Results of the EEG study showed that inhalation of MAO significantly changed the EEG power spectrum values of relative gamma, relative fast alpha, and spectral edge frequency 90%. During the inhalation of MAO, the value of relative fast alpha was significantly increased (p<0.05). On the other hand, the values of gamma and the spectral edge frequency 90% were significantly decreased (p<0.05). The present study suggests that fragrant chemicals of essential oil of M. arvensis reduce the level of mental stress and that they could be used in the treatment of psychophysiological disorders.

• Journal of Life Science
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• v.23 no.3
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• pp.443-447
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• 2013

This study was conducted to investigate the antimicrobial and anti-oral malodor effect of Schizandra chinensis extracts against oral pathogens. S. chinensis methanol (MeOH) extract showed better antimicrobial activities against oral pathogens than the S. chinensis hot water extract did. In particular, ethylacetate (EA) fraction of S. chinensis MeOH extract had the greatest effects against Streptococcus mutans, S. sanguinis, S. salivaris subsp. thermophols and Porphyromons gingivalis. The anti-malodor effect of S. chinensis against the generation of volatile sulfur compounds (VSC), such as hydrogen sulfide, methyl mercaptan, and dimethyl sulfide, was estimated using oral chroma in a practical study. The results showed that 2% MeOH extract of S. chinensis against the production of hydrogen sulfide, methyl mercaptan, and dimethyl sulfide had inhibitions of 91.15, 78.72 and 71.58%, respectively. These results showed that Schizandra chinensis extract had antimicrobial activity against several oral pathogens and exhibited significant effects on the inhibition of VSCs. Thus, Schizandra chinensis extract could be an alternative to available synthetic chemicals and oral hygiene products.

• Journal of Life Science
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• v.26 no.10
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• pp.1113-1120
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• 2016

Two bacterial strains producing extracellular man nanase were isolated from doenjang, a traditionally fermented soybean paste in Korea. The isolates, WL-6 and WL-11, were identified as Bacillus subtiis on the basis of their 16S rRNA gene sequences, morphological, and biochemical properties. Two genes encoding the mannanase of both B. subtilis WL-6 and B. subtilis WL-11 were each cloned into Escherichia coli, and their nucleotide sequences were determined. Both mannanase genes consisted of 1,086 nucleotides, encoding polypeptides of 362 amino acid residues. The deduced amino acid sequences of the two WL-6 and WL-11 mannanases, designated Man6 and Man11, respectively, differed from each other by eight amino acid residues, and they were highly homologous to those of mannanases belonging to the glycosyl hydrolase family 26. The 26 amino acid stretch in the N-terminus of Man6 and Man11 was a predicted signal peptide. Both Man6 and Man11 were localized at the level of 94–95% in an intracellular fraction of recombinant E. coli cells. The enzymes hydrolyzed both locust bean gum and mannooligosaccharides, including mannotriose, mannotetraose, mannopentaose, and mannohexaose, forming mannobiose and mannotriose as predominant products. The optimal reaction conditions were 55°C and pH 6.0 for Man6, and 60°C and pH 5.5 for Man11. Man11 was more stable than Man6 at high temperatures.

• Journal of Life Science
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• v.26 no.10
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• pp.1218-1223
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• 2016

Abalones are gastropod mollusks belonging to the genus Haliotis. Fishery products are continuously declining worldwide while abalone production from aquatic farms has considerably increased. Although abalones are regarded as very important marine resources and considered to have big potential in sea-food farming industry around world, the slow growth rate of Pacific abalones is considered to be one of the most serious problems. For the genetic improvements in cultured abalone, advances in various breeding techniques for abalone have been reached through the introduction of selection, crossbreeding, hybridization, and polyploidy in several commercially important abalone species. Six species of abalone have been reported to be distributed along the coasts of Korea: Haliotis discus hannai, Haliotis discus discus, Haliotis madaka, Haliotis gigantea, Haliotis diversicolor diversicolor, and Haliotis diversicolor supertexta. The hybridization between these abalones may be one of the advanced technologies, and the preliminary experiments of interspecific hybrids between abalone species distributed in northern pacific areas including Korea, China, and Japan have been conducted. In this study, we reviewed the phylogenetic relationship of northern pacific abalone species which have the potential traits for aquaculture in Korea and their identifications. We also examined the development of molecular markers and some other aspects of the genetic approaches for successful development of hybrids.

• Korean Journal of Plant Resources
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• v.28 no.5
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• pp.648-655
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• 2015

Balloon flower (Platycodon grandiflorum A. DC.) is a perennial plant of mainly Campanulaceae family, which have been widely used as a food ingredient and herbal medicine in East Asia. Although demands on related products and yearly cultivation area for balloon flower are increasing, diverse fundamental technologies and molecular breeding studies are not very well supported in Platycodons. In this study, 30 random amplification of polymorphic DNA (RAPD) primers were test in an attempt to explore genetic diversities. In addition, sequences information of the actin gene, a well conserved gene encoding a globular protein that forms microfilaments, was retrieved and analyzed. Two actin homologs were recovered; 3.4 kb fragment is a Pg-actin and 1.4 kb fragment is a Pg-actin homolog with 28.6% similarity. We have confirmed that the Pg-actin gene is configured into 4 exons and 3 introns. A single nucleotide polymorphism (SNP), G↔A, was detected on the intron 3, which served as a target for the CAPS marker development. The marker Pg-Actin-Int3 was applied to 32 balloon flower accessions. Balloon flower DNA sequence information generated in this study is expected to contribute to the analysis and molecular breeding and genetic diversity analysis of balloon flowers.

• Korean Journal of Medicinal Crop Science
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• v.21 no.6
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• pp.444-454
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• 2013

The development of random amplified polymorphic DNA (RAPD) and expressed sequence tag-derived simple sequence repeats (EST-SSRs) provided a useful tool for investigating Korean ginseng genetic diversity. In this study, 18 polymorphic markers (7 RAPD and 11 EST-SSR) selected to assess the genetic diversity in 31 ginseng accessions (11 Korean ginseng cultivars and 20 breeding lines). In RAPD analysis, a total of 53 unique polymorphic bands were obtained from ginseng accessions and number of amplicons ranged from 4 to 11 with a mean of 7.5 bands. Pair-wise genetic similarity coefficient (Nei) among all pairs of ginseng accessions varied from 0.01 to 0.32, with a mean of 0.11. On the basis of the resulting data, the 31 ginseng accessions were grouped into six clusters. As a result of EST-SSR analysis, 11 EST-SSR markers detected polymorphisms among the 31 ginseng accessions and revealed 49 alleles with a mean of 4.45 alleles per primer. The polymorphism information content (PIC) value ranged from 0.06 to 0.31, with an average of 0.198. The 31 ginseng accessions were classified into five groups by cluster analysis based on Nei's genetic distances. Consequently, the results of ginseng-specific RAPD and EST-SSR markers may prove useful for the evaluation of genetic diversity and discrimination of Korean ginseng cultivars and breeding lines.