• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2000년도 추계학술발표논문집
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• pp.83-83
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• 2000

Alkylketene dimer was known as a cellulose reactive or alkaline size because it does not require to fix to the fiber as do the traditional rosin sizes. A proposed sizing mechanism of AKD was the formation of P -ketoester bond between AKD and cellulose which provides the permanent attachment and the orientation of the hydrophobic alkylchains outward. However, some questions about the reaction had arisen and thus, the sizing mechanism of AKD has been a subject of controversy for several decades. The major concern of the controversy is that AKD is really reactive with cellulose or not in the papermaking conditions. In this study, reaction between AKD and pulp fiber was investigated, in order to find out whether AKD forms P-ketoester with pulp fiber during aging under no catalyzed neutral condition with obvious spectroscopic evidence. In addition, effect of aging treatment on the sizing development was studied. It has been disclosed that, in absence of water, AKD reacted with cellulose to form P -ketoester linkage under no catalyzed neutral condition, while, in presence of water, most of AKD was hydrolyzed to a dialkyl ketone or P -ketoacid. In addition, during the aging treatment of AKD-sized paper, its typical IR spectra bands gradually were reduced, completely disappeared after 6hr aging, and formed new absorption bands at 1707cm-' and shoulder peak at 1700cm-' which refer to the typical dialkylketone absorption bands. Therefore, the formation of P -ketoester between AKD and pulp fiber is impossible in the practical papermaking process. It could be suggested that the sizing development of AKD-sized paper is obtained by next two mechanism: 1) formation of a thin-layer of AKD on the fiber surface through melting and spreading of AKD emulsion particles by heat and 2) the hydrolysis of AKD to dialkyl ketone which has higher melting point, during drying and storage of AKD sized papers.

• 한국환경보건학회지
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• 제31권6호
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• pp.498-503
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• 2005

Stability of soybean isoflavone isomers according to extraction conditions such as temperature, pH, and extracting solvents was investigated. Heating induced three chemical reactions to occur for malony1 derivatives of isoflavones, namely decarboxylation of malony1 groups into acety1 derivatives, deesterification of malony1 residues, and hydrolysis of $\beta$-glycosidic bonds. Among the twelve isoflavone isomers, change in concentrations of acety1glycosides were most pronounced: Acety1 derivatives were present only in trace amounts in unheated hypocotyls, but the content increased dramatically during heating. As for the glycosides, concentrations of daidzin and glycitin increased due to heat treatment, though that of genistin remained almost unchanged. Heat decomposition rates and the patterns differed among the three malony1 derivatives. After 120 min at $80^{circ}C$, the relative concentrations of daidzin, glycitin and genistin were increased from $9.2\%$, $12.4\%$ and $3.3\%$ to $19.3\%$, $21.9\%$ and $6.2\%$, respectively. When crude isoflavones were solubilized in glycine buffer (pH 10.0) and incubated at $80^{circ}C$, deesterification occurred faster than at pH 7.0. When the pH of isoflavone solution was increased, the malony1glycosides were hydrolyzed to their respective glycosides at increased rate. Both acetyl and aglycone forms were unchanged and only de-esterification reactions occurred. At the acidic pH, malonylglycosides were much stable both at 60 and $80^{circ}C$. However at pH 10, $80^{circ}C$ and 1 hr, $75-80\%$ of malonylglycosides were transformed to their deesterified glycosides. When isoflavones were extracted with $60\%$ aqueous ethanol at $60^{circ}C$, isoflavone isomers were stable and the deesterification reactions did not occur in these conditions. However, at $80^{circ}C$ deesterification of malonyiglycosides occurred significantly with $15-20\%$ of malonylglycosides being hydrolyzed into their respective glycosides. This experiment showed that malonylglycosides undergo decomposition when heated or exposed to alkaline conditions. Also, aqueous ethanol was preferred to aqueous methanol as solubilizing media for obtaining extract with minimum degradation of malonylglycosides.

• Journal of Microbiology and Biotechnology
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• 제9권6호
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• pp.778-783
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• 1999

Campylobacter is a pathogen for both humans and animals that can be transferred from animals to humans. Four isolates, which grew under 5-10% $CO_2$ and had small and translucent colonies, were obtained from swine gastric mucosa and characterized using various methods. These bacteria were gram negative, spirally shaped with round ends. One or two non-sheathed polar flagella were observed under electron microscopy. A PCR with species-specific protein (SSP) primers for 16S rRNA gene in Campylobacter produced a typical 462 bp fragment. The isolates had various biochemical and molecular characteristics which differentiated them from other Campylobacters. The isolates were catalase and oxidase positive, urease (rapid) negative, nitrate reduction positive, indoxyl acetate hydrolysis positive, y-glutamyl transpeptidase negative, and alkaline phosphatase negative. All four isolates showed growth at $37^{\circ}C{\;}and{\;}42^{\circ}C{\;}but{\;}not{\;}at{\;}25^{\circ}C$, were resistant to cephalotin and cefoperazone, and susceptible to carbenicillin. The isolates showed various results in the reduction of chloride to triphenyl tetrazolium (TTC) and a susceptibility to nalidixic acid. Western blot analysis of these isolates with antiserum raised against one isolate showed different patterns from those of reference strains. A dendrogram drawn with the RAPD results showed that these isolates belonged to a new Campylobacter spp. group different from those of C. jejuni, C. doylei, C. lari, and C. coli.

• 한국균학회지
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• 제28권1호
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• pp.16-21
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• 2000

식용버섯 인공재배시 수분조정제로 아크릴아미드와 아릴설폰산염의 공중합물의 가수분해물인 CPAM-AS-hyd-1의 흡수겔을 첨가하여 각종 식용버섯의 균사생장 및 자실체 수량에 영향을 살펴본 결과 배지 100cc에 200g까지의 첨가는 균사생장에 큰 영향을 미치지 많았다. 식용버섯 생산을 위한 흡수겔의 적정 농도는 배지 100 cc에 대하여 느타리버섯의 경우는 200 g, 노루궁뎅이버섯은 $200{\sim}250\;g$, 팽이버섯은 200 g 첨가시 양호하였으며, 팽이버섯 재배시 폴리머 흡수겔과 10%(v/v)의 평화왕겨 첨가가 수량증대에 효과적이었다.

• 한국식품영양과학회지
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• 제35권2호
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• pp.248-253
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• 2006

식품내의 비타민 E를 분석하는 방법은 여러 가지 방법이 있으나 최근에는 비타민 E의 8가지 동족체를 모두 분석할 수 있는 HPLC 방법 이 가장 많이 이용되고 있다. 비타민 E를 분석함에 있어 가장 중요한 과정은 식품으로부터 비타민 E를 추출하는 과정이며 검화방법, 직접용매추출법, Soxhlet 추출법 등이 이용되고 있다. 본 연구에서는 곡류 14종을 대상으로 세 가지 추출방법을 비교하였으며 직접용매추출법과 Soxhlet 추출법을 이용하였을 경우 검화방법보다 높은 분석치를 얻을 수 있었다. 곡류에서의 비타민 E의 함량을 측정한 결과를 a-TE로 나타내었으며 흑미에서 5.12 a-TE/100g으로 가장 높았고 기장에서 0.32 a-TE/100 g으로 가장 낮은 함량을 나타내었다.

• 한국식품과학회지
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• 제20권3호
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• pp.433-440
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• 1988

천연 멸치추출액의 수율과 관능적 품질의 향상을 위하여 마른 중멸치를 0.3N NaOH알칼리 용액으로 마쇄하고 $60^{\circ}C$에서 1시간, 3시 간, 5시간 처리한 뒤 중화시켜 알칼리성 및 중성단백질 분해효소로 4시간 동안 가수분해 시켰다. 알칼리 처리한 시료를 효소반응 시간별로 멸치 마쇄용액을 취하여 원심 분리시킨 상등액에 함유된 가용성 고형분, 단백질, 무기질 그리고 맛과 냄새에 대한 관능적 품질을 평가하였다. 그 결과 고형분의 수율은 0.3N NaOH로 5시간 처리한 시료에 alkaline protease로 1시간 반응시켰을때, 최고 76.4%가 회수되어 물로만 추출한 대조구보다 약 4배의 수율이 향상되었고. 조단백질의 수율은 최고 65.3%로 약 3.2배 였으며, 회분의 수율은 30-47%의 회분 수율범위를 보여 12.9%였던 대조구에 비하여 현저하게 증가하였다. 또한 맛이나 냄새와 같은 관능적 품질에서도 그 강도가 2-3배의 향상효과가 있었으며 효소를 처리한 시료의 기호도가 현저히 향상됨이 밝혀졌다. 이상의 결과에서 고형분, 단백질 및 회분수율과 관능적 품질을 고려할때 알칼리처리 3시간후 단백질분해 효소로 1-3시간 처리함이 멸치 추출액의 수율과 관능적 품질에 가장 좋은 것으로 평가되었다.

• Applied Biological Chemistry
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• 제18권4호
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• pp.188-193
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• 1975

우리나라의 산간지방(山間地方)에 야생(野生)하는 머루중(中)의 anthocyanin의 구조(構造)를 확인(確認)하였다. 머루에서 0.5% HCl methanol로 추출(抽出)하여 얻은 색소(色素) 추출액(抽出液)을 Amberlite IRC-50 이온 교환수지관(交換樹脂管)을 통과(通過)시켜 정제(精製)하고, Paper chromatography에 의하여 개별색소(個別色素)를 분리(分離)하였다. 각(各) 개별색소(個別色素)에 대하여 부분(部分) 산가수분해(酸加水分解), 결합당(結合糖)의 확인시험(確認試驗), aglycone의 alkali 분해(分解), paper chromatography에서 얻어진 $R_f$치(値), 가시부(可視部)에서의 흡수(吸收) spectra 측정(測定) 등에 의하여 구조(構造)를 확인(確認)하였다. 확인(確認)된 머루중(中)의 7가지 색소(色素)는 delphinidin 3-monoglucoside, petunidin 3-monoglucoside, cyanidin 3-monoglucoside, delphinidin 3,5-diglucoside, malvidin 3-monoglucoside, petunidin 3,5-diglucoside 및 malvidin 3,5-diglucoside 이었으며 cyanidin 3,5-diglucoside로 추측되는 색소(色素) 4-b는 확인(確認)되지 못하였다.

• 분석과학
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• 제13권5호
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• pp.592-600
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• 2000

담즙내 지방산의 농도와 그 조성이 콜레스테롤의 과포화와 마찬가지로 담석 형성 과정에 관련이 있는 것으로 여겨지고 있다. 본 연구에서는 gas chromatography-mass spectrometry (GC-MS)의 selected ion monitoring (SIM) 방법을 이용하여 담즙내 23종의 지방산 동시 분석을 시도하였다. 전처리 과정의 첫 단계로 유리 지방산과 인지질 지방산을 분리하기 위해 aminopropyl column을 사용하였고 GC-MS에서의 검출을 위하여 유리 지방산은 MSTFA/TMCS 혼합액으로 유도제화를 실시하였으며 인지질 지방산의 경우는 염기를 이용한 가수분해를 실시한 뒤 위와 동일한 과정으로 유도제화하였다. 이 때의 회수율은 61.1-99.0% 이었으며 각각 3.1-25.6%와 3.8-27.0%의 within-a-day와 day-to-day 분석의 RSD 값을 얻었다. 이 방법을 적용하여 정상인과 담석증 환자의 담즙내에 존재하는 유리 및 인지질 지방산의 농도를 알아보았으며 이 때 각 물질들의 농도와 분포가 두 군간에 차이를 나타냄을 알 수 있었다.

• 공업화학
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• 제5권2호
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• pp.230-237
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• 1994

Aliquat 336 상이동촉매에 의한 n-butyl acetate의 알칼리 가수분해반응을 액-액 불균일 반응계로 한 반응기구를 준1차반응 모델, 계면반응 모델 및 본체반응 모델로 나타내어 복잡한 액-액 불균일계 반응을 간단히 취급할 수 있었다. 분산교반조를 사용하여 측정한 반응전화율로부터 준1차반응 모델과 계면반응 모델 그리고 평면교반조로부터 본체반응 모델로서 반응기구를 각각 설명할 수 있었으며, 각 모델로부터 구한 반응속도상수는 $25^{\circ}C$에서 각각 $3.1{\times}10^{-4}$, $7.3{\times}10^{-4}$, $6.6m^3/kmol.s$이었다.

• 한국식품영양학회지
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• 제23권2호
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• pp.233-239
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• 2010

Phenolic acid concentrates of rice bran(RB-ex) and hydroxycinnamic acids were investigated for their anti-hyperglycemic activities through glucose uptake and glucokinase activity using HepG2 cells and stimulatory effects on insulin secretion using HIT-T15 cells. RB-ex was prepared as an ethylacetate extract after alkaline hydrolysis and hydroxycinnamic acids, found as major compositions of RB-ex, such as ferulic acid(FA), sinapic acid(SA) and p-coumaric acid(p-CA) were investigated to compare with the properties of RB-ex. The properties of glucose uptake in HepG2 cells were examined in the absence of insulin and two different glucose concentrations(5.5 mM and 25 mM). RB-ex and FA showed anti-hyperglycemic activities through the increase of glucose uptake and the stimulation of glucokinase activity in HepG2 cells. RB-ex exhibited higher glucose uptakes with higher glucose concentrations, whereas FA exhibited the same increasing effects on both concentrations of glucose. RB-ex and FA exhibited doubled glucokinase activities relative to control. In the presence of insulin in the 25 mM glucose-containing medium, the levels of glucose uptake were increased in all treatments compared with control. As stimulatory effects of samples on insulin secretion were estimated, RB-ex and FA stimulated insulin secretion at a concentration of 25 ${\mu}g/m{\ell}$ and in particular, FA showed the highest amount of insulin-release in HIT-T15 cells. Antioxidative effects on HIT-T15 cells, RB-ex and hydroxycinnamic acids, excluding p-CA, showed inhibitory activities of 78% to 80% at a concentration of 100 ${\mu}g/m{\ell}$. On the basis of these results, we conclude that RB-ex and FA could help decrease blood glucose levels and prevent the cell damages via antioxidant activity.