• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.301-304
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• 1988

A pH-meter has been newly developed by using on ISFET as the ion sensing element. The performance characteristics of the developed pH-meter have been investigated and confirmed to be used practically. The stable operation and the temperature compensation were stressed in this study.

• Archives of Pharmacal Research
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• 제20권6호
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• pp.643-646
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• 1997

Thermal stability of a red pigment, carthamin, frm Carthamus tinctorius was investigated to explore possible applications as natural color additives for foods, cosmetics, and nutraceuticals. Degree of degradation reactions of carthamin at acidic, neutral and alkaline conditions were determined with UV/V is spectral measurements. Decomposition half lives of carthamin at 25.deg. C were 4.0 h, 5.1 h, and 12.5 h at pH 5.0, pH 7.0, and pH 12.0, respectively, indicating that carthamin is much more stable at alkaline pH than acidic or neutral conditions. The activation energies of carthamin at pH 5.0, pH 7.0, and pH 12.0 were 15.6, 15.7 and 16.8 kcal/mol, respectively.

• Applied Biological Chemistry
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• 제12권
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• pp.7-11
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• 1969

Mucor-rennin, the crystalline milk-clotting enzyme, isolated from Mucor pusillus var. Lindt, has an acid protease activity. The optimum pH for the digestion of k-casein is 4.5, while that for hemoglobin digestion is 4.0. The skim milk solution was easily clotted acidic solution than alkalin solution, and the milk clotting activated by Ca ion. The enzyme was heat stable against heat from pH 4.0 to 6.0 but was more stable at pH 5.0. The activity of the enzyme at pH 5.0 did not decrease at 30 C for 15 days and the activity was not effected by sodium propionate and salicilic acid. Therefore, the enzyme of liguid type could store for a long time and could be transported from Erzyme production Co. to Manufacture of cheese Co. by adding the antiesptic and by adjusting pH to 5.0.

• 대한전자공학회논문지
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• 제19권6호
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• pp.52-54
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• 1982

p·Si-전해질 접합을 전해질로 6N H2SO4, 6N H2SO4(Ti3+), 6N H2SO4(Ti4+), 6N H2SO4(Ti4+/Ti3+)을 사용하여 만들었다. 이들 전해질중 6N H2SO4(Ti4-/Ti3+)을 사용할 때 p·Si 광음극이 안정하게 동학하며 높은 광전 감도를 가지고 있었다. p·Si-electrolyte junction are prepared by using p·Si photocatode in four different electrolytes such as 6N H2SO4, 6N H2SO4(Ti3+), 6N H2SO4(Ti4+), 6N H2SO4(Ti4+/Ti3+) respectively. Among those electrolytes 6N H2SO4(Ti4-/Ti3+) shows very good results, in which p·Si photocathode is stable.

• 한국식품조리과학회지
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• 제12권4호
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• pp.506-510
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• 1996

제주도에서 생산된 선인장 열매의 적색 betanine 색소를 천연착색료로 사용하기 위하여 pH, 금속이온, 당 및 산의 영향을 조사하였다. 선인장 열매 색소액을 음료의 천연착색료로 사용할 때의 색소농도는 2.5% 가장 선호되었다. pH 영향에서 산성범위인 pH 4와 5에서 색소액이 비교적 안정하였으며 Fe 및 Cu 이온이 색소의 변화에 큰 영향을 주었으나 Sn이온에 의하여 색소의 안정성이 감소되지 않았다. 선인장 열매 색소액에 0.15M, 0.3 M의 포도당과 과당 및 자당 0.075 M, 0.15 M을 첨가하였을 때 대조군에 비하여 안정성이 감소되지 않았으며 과당 0.15 M 첨가군은 고유한 붉은색을 안정화시키는 결과를 가져왔다 또 한 tartaric, phophoric, citric acid 100, 500 ppm을 첨가 한 경우에도 대조군에 비하여 색소안정성의 변화를 보이지 않았으나 100, 500ppm의 ascorbic acid는 항산화 효과를 보여 색소의 안정성을 상승시켰다. 이상에서 제시한 바와 같이 선인장 열매의 적색색소가 합성색소에 비하여 안정성이 비교적 약하므로 색소의 안정성을 증가시키기 위한 많은 연구가 수행되어야 하며, 현재까지의 결과로 미루어 보아 제한된 조건에 서 선인장 열매를 음료의 천연착색료로 사용하여야 하겠다.

• Journal of Microbiology and Biotechnology
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• 제23권5호
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• pp.661-667
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• 2013

Lipase-producing bacterial strains were isolated from Antarctic soil samples using the tricaprylin agar plate method. Seven strains with relatively strong lipase activities were selected. All of them turned out to be Bacillus pumilus strains by the 16S rRNA gene sequence analysis. Their corresponding lipase genes were cloned, sequenced, and compared. Finally, three different Bacillus pumilus lipases (BPL1, BPL2, and BPL3) were chosen. Their amino acid sequence identities were in the range of 92-98% with the previous Bacillus pumilus lipases. Their optimum temperatures and pHs were measured to be $40^{\circ}C$ and pH 9. Lipase BPL1 and lipase BPL2 were stable up to $30^{\circ}C$, whereas lipase BPL3 was stable up to $20^{\circ}C$. Lipase BPL2 was stable within a pH range of 6-10, whereas lipase BPL1 and lipase BPL3 were stable within a pH range of 5-11, showing strong alkaline tolerance. All these lipases exhibited high hydrolytic activity toward p-nitrophenyl caprylate ($C_8$). In addition, lipase BPL1 showed high hydrolytic activity toward tributyrin, whereas lipase BPL2 and lipase BPL3 hydrolyzed tricaprylin and castor oil preferentially. These results demonstrated that the three Antarctic Bacillus lipases were alkaliphilic and had a substrate preference toward short- and medium-chain triglycerides. These Antarctic Bacillus lipases might be used in detergent and food industries.

• 전기화학회지
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• 제11권4호
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• pp.304-308
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• 2008

Noble Poly (lithium 2-acrylamido-2-methyl propane sulfonate) and its copolymer with N-vinyl formamide based on trihexyl (tetradecyl) phosphonium acetate [$(C_6H_{13})_3$ P ($C_{14}H_{29}$) $CH_3COO$; $P_{66614}$ $CH_3COO$] and trihexyl (tetradecyl)phosphonium bis(trifluoromethane sulfonyl) amide ([$(C_6H_{13})_3P(C_{14}H_{29})$] [TFSA];$P_{66614}TFSA$) were prepared and analyzed to determine their characteristics and properties. The ionic conductivity of a copolymer based $P_{66614}TFSA$ ionic liquid system exhibits a higher conductivity ($8.9{\times}10^{-5}Scm^{-1}$) than that of a copolymer based $P_{66614}CH_3COO$ system ($1.57{\times}10^{-5}Scm^{-1})$. The charge on the TFSA anion is spread very diffusely through the S-N-S core and particularly in the trifluoromethane groups, and this diffusion results in a decreased interaction between the cation and the anion. The viscosity of $P_{66614}TFSA$ (39 cP at 343 K) and $P_{66614}CH_3COO$ (124 cP at 343 K), which is very hydrophobic, was fairly high. High viscosity leads to a slow rate of diffusion of redox species. The ionic conductivity of copolymer of a phosphonium ionic liquid system also exhibits higher conductivity than that of a homopolymer system. Phosphonium ionic liquids were thermally stable at temperatures up to $400^{\circ}C$.

• Food Science and Biotechnology
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• 제15권2호
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• pp.177-182
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• 2006

Polyphenol oxidase (PPO) was isolated from the flesh of Fuji apples by DEAE-Cellulose, ammonium sulfate precipitation, phenyl-Sepharose CL-4B, and Sephdex G-100 chromatography. The molecular mass of the purified PPO was estimated to be 40 kDa by SDS polyacrylamide gel electrophoresis. With regard to substrate specificity, maximum activity was achieved with chlorogenic acid as substrate, followed by catechin and catechol whereas, there was no detectable activity with hydroquinic acid, resorcinol, or tyrosine as substrate. The optimum pH and temperature with catechol as substrate were 6.5 and $35^{\circ}C$, respectively. The enzyme was most stable at pH 6.0 and unstable at acidic pH. The enzyme was stable when it was heated to $45^{\circ}C$ but heating at $50^{\circ}C$ for more than 30 min caused 50% loss of activity. Reduced $ZnSO_4$, L-cystein, epigallocatechin-3-o-gallate (EGCG), and gallocatechin gallate (GCG) also inhibited activity.

• Applied Biological Chemistry
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• 제13권3호
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• pp.231-235
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• 1970

1. 내열성 사상균 Humicola속의 Amylase를 정제하였다. 2. DEAE-Cellulose Column Chromatography로 2개의 활성구분으로 나누어 졌다. 3. 즉 pH 6.0, 0.05M와 0.5M의 인산염완충용액으로 용출시킬때 전자에서 당화형, 후자에서 호정화형 Amylase가 각각 분리되었다. 4. 이 당화형 Amylase의 최적 pH는 $4.5{\sim}5.5$이고, 안정 pH 범위는 $4.0{\sim}9.0$범위였다. 최적온도는 $60{\sim}65^{\circ}C$로 다른 사상균의 그것보다 훨씬높고 $80^{\circ}C$ 이상에서는 불활성화 되었다.

• Applied Biological Chemistry
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• 제21권2호
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• pp.103-108
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• 1978

Paecilomyces subglobosum이 생산하는 내산성 ${\alpha}-amylase$를 Sephadex G-150으로 정제한 결과 순수정제가 되지 않았으나 glucoamylase와 분리되었다. 조효소를 사용하여 내산성 amylase의 일반 성질을 조사한 결과 최적 pH는 4.0이었고 최적온도는 $38^{\circ}C$이었다. 이 효소는 보통 ${\alpha}-amylase$와 비교하여 pH에 대한 안정성은 매우 좋았으나 열 안정성은 비슷하였다. 전분에 대한 가수분해력이 좋았으며 생성물을 박충 크로마토그라피로 조사한 결과 말토스도 분해하는 것을 알았다.