• 한국축산식품학회지
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• 제32권4호
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• pp.428-433
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• 2012

The objective of this study was to identify appropriate aging conditions, changes in nucleotide-related compounds, chemical changes, and a sensory evaluation of duck meat during aging at $0^{\circ}C$ for 7 d. Twenty one 45-day-old Pekin white ducks samples were separated into breast and leg meat. ATP was not detected for almost the entire aging period because ATP was depleted immediately after slaughter. Inosine monophosphate (IMP) was highest on day 1 ($26.69{\mu}mol/g$), and then it rapidly decreased to $7.11{\mu}mol/g$ on day 7. However, this level was not different between breast and leg meat. Hypoxanthine (Hx) content of breast meat was $14.88{\mu}mol/g$, whereas that of leg meat was $16.41{\mu}mol/g$. Inosine content of breast meat was double than that of leg meat. The pH values of breast and leg meat were 5.90-6.05 and 6.23-6.73, respectively, during the aging period. Volatile basic nitrogen content of breast and leg meat increased during aging. Breast meat had good sensory evaluation scores for flavor (7.4), juiciness (6.8), tenderness (7.2), and overall acceptance (7.4) on day 3. Similar to breast meat, leg meat also had good sensory evaluation scores. Therefore, it is concluded that the appropriate aging period is 3 d for duck breast meat and 1 day for leg meat at $0^{\circ}C$.

• KSBB Journal
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• 제14권2호
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• pp.205-211
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• 1999

본 연구에서는 A.cycloclast ATCC 21921 균주를 사용하여 $\gamma$-butyrobetaine으로부터 L-carnitine을 생산하는 최적 조건에 대한 연구를 수행하였다. 배양액 내에 $\gamma$-butyrobetaine 만을 포함하였을때는 최대 L-carnitine 생산량이 29g/L이었고 전환수율도 30.9 mol%로 매우 낮았다. L-carmtine 생산에 미치는 탄소원의 영향을 관찰한 결과 glycerol을 첨가할 경우 L-carnitine 생산량이 4.6g/L 그리고 전환수율이 88.2 mol%로 $\gamma$-butyrobetaineaks을 포함하였을 때보다 월등히 향상되었다. Betaine, chohne와 같은 quaternary ammonium compounds 들이 L-carnitine 생산에 미치는 영향을 조사해본 결과, 이들에 의하여 L-carntine 생산 속도가 빨라지고 전환수율도 증가함을 알 수 있었다. 한편, 기질인 $\gamma$-butyrobetaine 농도 3% 이상에서 세포 생장은 저해되고 L-carnitine 생산은 기질 농도 2-3%에서 가장 우수함을 알 수 있었다. 본 연구에서 구한 최적 생산 조건, 다시 말해서 glycerol과 choline을 배양액에 포함하고 기질의 농도를 2%^로 하여 플라스크에서 회분식 배양을 하였을 때, 배양 4일 만에 최대 7.2g/L의 L-carrutine을 생산할 수 있었고 이때 $\gamma$-butyrobetaine으로부터 L-carnitine에로의 전환수율은 98.7mol%이었다.

• 한국식품영양과학회지
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• 제33권7호
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• pp.1175-1179
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• 2004

Scale-up하기 위하여 24시간동안 1：2：2의 몰 비율로 stirred-batch type reactor에서 합성된 재구성지질은 capric acid와 CLA를 각각 4.9 mol%와 4.1 mot% 함유하였다. 기능성 지방산인 capric acid와 CLA는 주로 TAG의 sn-1,3 position에 분포하였고, sn-2 position에는 linoleic acid가 대부분을 차지하였다. 재구성지질과 대두유의 요오드가는 각각 126와 114이었고, 비누화가는 각각 190과 194로 측정됨으로써, 재구성 지질의 TAG에서 capric acid의 함유를 확인할 수 있었다. 대두유와 재구성지질의 tocopherol함량은 각각 74.6 mg/100 g과 18.2 mg/100 g으로, 재구성지질의 tocopherol 함량은 대두유보다 약 76% 감소하였다. 색도분석 결과, 재구성 지질과 대두유간에 백색도(L＊)와 적색도(a＊)에서는 유의적 차이가 없었으나(p＜0.05),황색도(b＊)에서 재구성지질이 대두유보다 좀더 yellowness를 보이며 유의적 차이를 보였다. (p＜0.05). Reversed-phase HPLC 분석 결과, 재구성지 질에서 capric acid를 함유하고 있는 TAG형태의 partition number (PN)는 25∼37로 약 12.57 area%이었음을 확인하였다. 대두유의 주된 crystallization peak는 -57.86$^{\circ}C$C이었으나, capric acid를 4.9 mol% 함유하고 있는 재구성지질의 crystallization peak는 -52.78$^{\circ}C$로 대두유보다 결정화가 좀더 고온에서 일어났다.

• Journal of Microbiology and Biotechnology
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• 제29권6호
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• pp.913-922
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• 2019

Magnetic $Ni_{0.7}Co_{0.3}Fe_2O_4$ nanoparticles that were prepared via the rapid combustion process were functionalized and modified to obtain magnetic $Ni_{0.7}Co_{0.3}Fe_2O_4@SiO_2-CHO$ nanocomposites, on which penicillin G acylase (PGA) was covalently immobilized. Selections of immobilization concentration and time of fixation were explored. Catalytic performance of immobilized PGA was characterized. The free PGA had greatest activity at pH 8.0 and $45^{\circ}C$ while immobilized PGA's activities peaked at pH 7.5 and $45^{\circ}C$. Immobilized PGA had better thermal stability than free PGA at the range of $30-50^{\circ}C$ for different time intervals. The activity of free PGA would be 0 and that of immobilized PGA still retained some activities at $60^{\circ}C$ after 2 h. $V_{max}$ and $K_m$ of immobilized PGA were 1.55 mol/min and 0.15 mol/l, respectively. Free PGA's $V_{max}$ and $K_m$ separately were 0.74 mol/min and 0.028 mol/l. Immobilized PGA displayed more than 50% activity after 10 successive cycles. We concluded that immobilized PGA with magnetic $Ni_{0.7}Co_{0.3}Fe_2O_4@SiO_2-CHO$ nanocomposites could become a novel example for the immobilization of other amidohydrolases.

• Bulletin of the Korean Chemical Society
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• 제28권10호
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• pp.1661-1664
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• 2007

Direct reaction of elemental silicon with a gaseous mixture of isopropyl chloride (1) and hydrogen chloride in the presence of copper catalyst using a stirred bed reactor equipped with a spiral band agitator gave isopropyldichlorosilane having a Si-H bond (2a) as a major product and isopropyltrichlorosilane (2b) along with chlorosilanes, trichlorosilane and tetrachlorosilane. A process for production of 2a was maximized using the 1:0.5 mole ratio of 1 to HCl and smaller size of elemental silicon at a reaction temperature of 220 °C. When a reaction was carried out by feeding a gaseous mixture of 1 [12.9 g/h (0.164 mol/h)] and HCl [2.98 g/h (0.082 mol/h)] to a contact mixture of elemental silicon (360 g) and copper (40 g) under the optimum condition for 45 h, 2a among volatile products kept up about 82 mol % until 35 h and then slowly decreased down 68 mol % in 45 h reaction. Finally 2a was obtained in 38% isolated yield (based on 1 used) with an 85% consumption of elemental silicon in a 45 h reaction. In addition to 2a, 2b was obtained as minor product along with chlorosilanes, trichlorosilane, and tetrachlorosilane. The decomposition of 1 was suppressed and the production of 2a improved by adding HCl to 1.

• KSBB Journal
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• 제25권5호
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• pp.459-465
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• 2010

A simple and efficient analytical method for the simultaneous determination of seven tar color additives was developed using ion pair high performance liquid chromatography. The conditions for HPLC analysis were as follows: column, ${\mu}$-Bondapak C18 (10 ${\mu}m$, 300 ${\times}$ 3.9 mm i.d.); gradient mobile phase, 0.025 mol/L ammonium acetate (containing 0.01 mol/L tetrabutylammonium bromide)-acetonitrile-methanol (65:25:10) as a mobile for fraction A and 0.025 mol/L ammonium acetate (containing 0.01 mol/L tetrabutylammonium bromide)-acetonitrilemethanol (40:50:10) as a mobile for fraction B; flow rate, 1.0 mL/ min; detection wavelength, 254/520/620 nm. We could attain to the detection limits as 0.01~0.05 ${\mu}$g/mL (254 nm) and 0.005~0.01 ${\mu}$g/mL (520 nm) for six red tar color additives, and 0.05 ${\mu}$g/mL (254 nm) and 0.002 ${\mu}$g/mL (620 nm) for Fast green FCF. This analytical method was applicable to determine the tar color additives contained in several commercial cold syrups.

• 한국식품영양학회지
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• 제19권2호
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• pp.219-226
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• 2006

마늘의 일시 대량 처리가 가능하고, 맛과 향미의 임의 조절이 가능하여 향신료의 품질을 균일화 및 표준화 시킬 수 있으며 유효 성분을 함유하고 있는 가공형태인 oleoresin을 제조하기 위하여 마늘의 ethanol 추출 조건에 의한 oleoresin의 최적 수율 및 thiosulfmate의 함량에 대하여 조사한 결과 시료 중량에 대한 용매의 적정 혼합 비율은 1:2(w/v)이었으며, 추출 온도와 시간은 각각 $30^{\circ}C$, 3 시간으로 조사되었으며 추출 횟수는 3번씩 추출하였을 때 oleoresin의 최적 수율 및 thiosulfinate의 함량은 각각 14.52%와 $209.93{\mu}mol/g$였다. 또한 위 조건 하에서 제조된 oleoresin의 향기 성분 분석 결과 diallyl disulfide, methyl allyl trisulfide, 3,4-dihydro-3vinyl-1,2-dithiin, 2-vinyl-4H-1,3-dithiin, diallyl trisulfide 등의 5종류의 마늘의 주요 향기 성분인 휘발성 황화합물이 검출되었다. Oleoresin의 저장시 품질 특성 변화를 조사하기 위하여 $4^{\circ}C$ 및 $25^{\circ}C$에서 30 일간 저장한 결과 thiosulfinate 함량이 $4^{\circ}C$에서는 $32.37{\mu}mol/g$으로 측정되었으나 $25^{\circ}C$ 저장시에는 거의 측정되지 않았다. 갈색도 및 탁도는 $25^{\circ}C$에서 저장하였을 경우 $4^{\circ}C$ 저장에 비해 현저히 증가하였으며, 산도의 경우 저장 온도에 관계없이 큰 변화를 보이지 않아 $4^{\circ}C$에서 저장시 마늘 oleoresin의 품질 특성이 좋게 나타났다.

• Preventive Nutrition and Food Science
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• 제16권2호
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• pp.104-109
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• 2011

Recently, we have demonstrated that green tea extract (GTE) decreases the intestinal absorption of benzo[a]pyrene (BAP), which is an extremely lipophilic food contaminant. The present study was conducted to examine if an enteral infusion of GTE would influence the biliary secretion of BAP and lipids in rats. Female rats were fed an AIN-93G diet with or without (control) GTE at 5 g/kg diet for 4 week. Following the 4-week dietary treatment, rats with bile duct cannula were infused continuously for 8 hr at 3.0 mL/hr via a duodenal catheter with a lipid emulsion containing $4.0\;{\mu}mol$ BAP labeled with $^{14}C$ ($^{14}C$-BAP), $20.7\;{\mu}mol$ cholesterol, $452\;{\mu}mol$ triolein, and $3.1\;{\mu}mol$ ${\alpha}$-tocopherol, and $396.0\;{\mu}mol$ Na-taurocholate with or without 76.1 mg GTE powder in PBS buffer (pH, 6.4). Bile was collected hourly via bile cannula for an 8 hr period. Our results showed that bile flow did not differ between groups. However, the biliary secretion of $^{14}C$-BAP was significantly enhanced by GTE infusion, compared with those infused with the lipid emulsion alone. However, GTE did not affect the biliary outputs of cholesterol, fat, phospholipid and ${\alpha}$-tocopherol. These findings indicate that GTE has a profound stimulatory effect on the biliary excretion of BAP in rats, without affecting other biliary lipids. The mechanism(s) by which GTE enhances the biliary secretion of BAP remains to be investigated.

• 한국전기전자재료학회논문지
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• 제17권11호
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• pp.1186-1191
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• 2004

ZnO varistor ceramics which were fabricated with variation of added of 0.5～1.0 mol% Co$_3$O$_4$, were sintered at 1150 $^{\circ}C$. In the specimen added 0.7 mol% Co$_3$O$_4$, sintered density was 6.03 g/㎤ and electrical properties were superior to any other compositions. The nonlinear coefficient a and clamping voltage ratio were 83 and 1.35, respectively. But, endurance surge current in the specimen added 0.5 mol% Co$_3$O$_4$ was 7000 A/$\textrm{cm}^2$, and deviation of varistor voltage was Δ-3.23 %. As P.C.T and T.C.T environmental test were succeed in all specimens, and deviation of varistor voltage in the specimen added 0.6 mol% Co$_3$O$_4$ was Δ-0.81 %. All specimens showed good leakage current property on the High Temperature Continuous Load Test(HTCLT) for 1000 hr at 85 $^{\circ}C$ and variation rate of the varistor voltage below Δ-2.0 %.

• 폴리머
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• 제24권6호
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• pp.886-892
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• 2000

폴리비닐페놀 (PVPh)을 LiOH로 중화시켜 중화도가 다른 여러 종류의 PVPh 이오노머 (PVPh-Li)를 제조하였다. 중화도에 따른 PVPh-Li의 $T_{g}$ 변화를 DSC로 측정한 결과 Li mol% 당 3.$8^{\circ}C$의 $T_{g}$ 증가가 관찰되었으며 유사한 구조를 지닌 poly(styrene-co-hydroxy styrene)의 3.$2^{\circ}C$ 증가에 비해 높은 수치이다. 이는 중화되지 않은 -OH가 -OLi와 강한 상호작용을 하기 때문인 것으로 생각되며, 이러한 상호작용으로 인해 -OLi 끼리의 클러스터 형성이 어려워져 소각X선산란 실험에서도 뚜렷한 피크가 관찰되지 않았다. 제조된 PVPh-Li를 PVPh와 블렌드시 50/50 조성의 경우 중화도가 10 mo1%인 PVPh-Li와 혼합되어도 상분리를 관찰할 수 없었으나, 폴리메틸메타크릴레이트 (PMMA)와 블렌드시 중화도가 5 mol%인 PVPh-Li가 혼합되면 거대 상분리를 관찰할 수 있었다. 이로부터 수소결합으로 인해 혼화성이 있는 블렌드라 하더라도 한 성분을 이오노머를 변환할 경우 새로운 강한 분자간 이온-다이폴 상호작용이 생성되지 않는 한, 아주 낮은 정도만 이오노머로 변환되어도 혼화성이 급격히 감소해 상분리가 관찰됨을 알 수 있었다.