• 한국식품영양과학회지
• /
• 제30권6호
• /
• pp.1041-1046
• /
• 2001

Fructose, glucose, sucrose 용액에 촉매를 가하지 않고 15$0^{\circ}C$, 17$0^{\circ}C$, 20$0^{\circ}C$에서 각각 가열하고 반응에 따른 카라멜 수용액의 색소형성, pH의 변화, 환원성 및 PPO에 대한 저해효과를 측정하고 이들 사이의 상관관계를 조사한 결과는 다음과 같다. 초기 카라멜화 생성물 및 갈색색소의 형성은 가열온도가 높고 시간이 길어짐에 따라서 증가하였으며, 세 당들 간에는 fructose>sucrose>glucose 카라멜 수용액 순서로 증가하였으며 (p<0.005) 반면에 pH는 감소하였다. 특히 20$0^{\circ}C$에서 가열한 당용액들은 pH 3.32~3.50 범위를 나타내었다. 카라멜 수용액의 환원성 및 PPO에 대한 그들의 저해효과는 가열 온도와 시간이 증가함에 따라서 각각 증가하였으며, 15$0^{\circ}C$와 17$0^{\circ}C$에서는 fructose>sucrose>glucose 카라멜 수용액 순서로 증가하였다(P<0.001). 그러나 20$0^{\circ}C$에서는 초기 단계에서는 fructose의 환원성이 가장 높았으나 후반부에서는 sucrose의 환원성이 크게 나타났는데 이는 형성된 CP의 차이에 기인된 것이라 생각된다. 카라멜 용액의 환원성은 reductones 화합물의 형성에 의한 것으로 생각되어진다. 또한 20$0^{\circ}C$에서 60분 가열한 sucrose 카라멜 수용액이 PPO활성을 34.6% 감소시켜 저해효과가 가장 높게 나타났다. 이로부터 카라멜 수용액의 PPO에 대한 저해효과는 카라멜 수용액의 환원성과 관련이 있는 것으로 생각되어진다.

• 미생물학회지
• /
• 제26권2호
• /
• pp.137-142
• /
• 1988

pH decreased as the substrate mycelium developed, $\Delta$pH was 1.05-1.15, but increased after the aerial mycelium formation. The lactic acid content in culture solution showed no difference between 0.2% and 5% glucose, at which the aerial mycelium formation was repressed. The growth and development of mycelium was delayed by the lactate treatment. The activity of catalase was maximum in 24 hours after inoculation, and the wuperoxide dismutase activity showed a constant level during the developmental phases. The ascorbic acid accumulated after the aerial mycelium formation. The ascorbate oxidase isozyme of Rf 0.44 appeared, while the isozyme of Rf 0.36 desappeared during the development.

• Food Science and Biotechnology
• /
• 제16권3호
• /
• pp.421-425
• /
• 2007

The inhibitory effect of onion extract on polyphenol oxidase (PPO) and browning of peach juice was investigated. Various reducing agents such as L-ascorbic acid, L-cysteine, dithiothreitol, glutathione, and sodium pyrosulfite strongly inhibited polyphenol oxidase extracted from peach. The enzyme was also inhibited by addition of water extract of onion. Regardless of substrates used, the addition of heated onion extract exhibited stronger inhibitory effect on peach polyphenol oxidase activity than that of the fresh one. The inhibitory effect of onion extract was dependent on heating temperature and time. The onion extract inhibited the peach polyphenol oxidase non-competitively. The heating of onion extract in the presence of glucose, glycine stimulated the inhibitory effect of the onion extract, which suggests non-enzymatic browning products produced during heating might be responsible for the stronger inhibitory action of the heated onion extract. The retardation of peach juice browning by onion extract seems to be caused by inhibition of peach PPO.

• 한국환경보건학회지
• /
• 제19권2호
• /
• pp.69-77
• /
• 1993

In the present study, the comparison of liver damage in carbon tetrachloride (CCl$_4$)-treated rats with that those pretreated with ethanol and an effect of liver injury on the serum and liver xanthine oxidase (XOD) activity were evaluated. The increasing rate of liver weight per body wt., the levels of serum alanine aminotransferase, and the decreasing rate of hepatic glucose-6-phosphatase activity and the protein contents in the liver cell were higher in carbon tetrachloride-treated animals pretreated with ethanol than the carbon tetrachloride-treated group. Especially, the histopathological findings also showed more severe liver damage in the ethanol-pretreated rats than the rats treated with carbon tetrachloride only. In such a experimental condition the xanthine oxidase activity of serum and liver both of carbon tetrachloride-treated rats and those pretreated with ethanol were higher than that of each control group. And the increasing rate of xanthine oxidase enzyme activity to the control group was higher in carbon tetrachloride-treated group pretreated with ethanol than those treated with CCl$_4$. In addition, the heptic uricase activity and the serum levels of uric acid were more increased in carbon tetrachloride-treated group pretreated with ethanol than those in the CCl$_4$-treated rats. On the other hand, there were no statistical differences in hepatic catalase and glutathione S-transferase activities between the CCl$_4$-treated rats and those pretreated with ethanol. In conclusion, it is assumed that the more severe liver damage in ethanol pretreated rats would be due to oxygen free radical produced by the xanthine oxidase system.

• 센서학회지
• /
• 제21권4호
• /
• pp.311-317
• /
• 2012

Disposable amperometric screen-printed biosensor strips have been fabricated by a sol-gel encapsulation for the analysis of glucose. The glucose oxidase(GOx) is entrapped in the gel matrix through sol-gel transition of tetraethoxysliane(TEOS). The biosensor is fabricated by GOx containing thin film of TEOS gel on the surface of screen-printed carbon electrode(SPCE). The GOx-containing thin film of TEOS gel offers a one-step modification process on the surface of SPCE. The optimum conditions for glucose determination have been characterized with respect to the applied potential, enzyme loading ratio, and pH. The linear range and detection limit of glucose detection were from 2.0 mM to 16.0 mM and 0.25 mM, respectively.

• 약학회지
• /
• 제46권5호
• /
• pp.331-336
• /
• 2002

The purpose of this study is to develop a non-invasive blood glucose measurement method by a portable near infrared (NIR) system which was newly integrated by our lab. The portable NIR system includes a tungsten halogen lamp, a specialized reflectance fiber optic probe and a photo diode array type InGaAs detector; which was developed by a microchip technology based on the lithography. Reflectance NIR spectra of different parts of human body (finger tip, earlobe, and inner lip) were recorded by using a fiber optic probe. The spectra were collected over the spectral range 1100 ∼ 1740 nm. Partial least squares regression (PLSR) was applied for the calibration and validation for the determination of blood glucose. The calibration model from earlobe spectra presented better results, showing good correlation with a glucose oxidase method which is a mostly used standard method. This model predicted the glucose concentration for validation set with a SEP of 33 mg/dL. This study indicated the feasibility for non-invasive monitoring of blood glucose by a portable near infrared system.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2003년도 생물공학의 동향(XIII)
• /
• pp.692-695
• /
• 2003

In this work immobilization technique of enzymes onto the magnetic nanoparticles has been developed for biochip applications. Glucose oxidase and lactate dehydrogenase were immobilized on magnetic nanoparticles via cyanamide and glutaraldehyde. Immobilized enzymes had good operational and storage stability The immobilized glucose oxidase and lactate dehydrogenase were characterized by some factors(pH, temperature, and components of buffer solution etc) which affect the activity, In order to characterize the magnetic nanoparticles, we have used transmission electron microscopy(TEM), X-ray diffraction(XRD) and Fourier transform infrared(FTIR).

• Journal of Microbiology and Biotechnology
• /
• 제10권1호
• /
• pp.51-55
• /
• 2000

Surface culture fermentation using Aspergillus niger was studied for gluconic and citric acid production at different C/N ratios. A culture of A. niger was found to produce either gluconic acid alone, a mixture of gluconic and citric acid, or citric acid alone depending on the level of nitrogen in the medium (4 to 18mM). Glucose oxidase from the mycelial mat was also analyzed at different levels of nitrogen in the media. By choosing the level of nitrogen in the medium at the start of fermentation, it is possible to produce either of the two acids as the dominant product or the two together as a mixture.

• 동의생리병리학회지
• /
• 제16권6호
• /
• pp.1197-1200
• /
• 2002

To examine the cardiotoxicity of glucose oxidase(GO) in cultured myocardial cells, cardiotoxicity was measured by MTT assay. Myocardial cells were treated with 1～50 mU/ml GO for 5 hours. The cardioprotective effect of Benincasae Semen(BS) was measured by MTT assay in these cultrures. Cell viability was significantly decreased in dose- and time-dependently after myocardial cells were exposed to 30mU/ml GO for 5 hours. In the cardioprotective effect of BS on the cardiotoxicity induced by GO, BS prevented the cardiotoxicity induced by GO in these cultures. From these results, it suggests that GO had cytotoxic effect in cultured myocardial cells and herb extract, BS showed protective effect on GO-induced cardiotoxicity.

• Toxicological Research
• /
• 제11권2호
• /
• pp.187-192
• /
• 1995

The cytotoxic effects of hydrogen peroxide and neuroprotective effects of a variety of agents were investigated in newborn mouse forebrain tissue culture. In our experiments, oxygen radical was generated enzymatically by glucose oxidase and the values were expressed as a percentage of number of living cells by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Cytotoxicity of oxygen radicals was prevented by catalase and (N, N, N', N', -tetrakis (2-pyridylmethyl) ethylenediamine (TPEN), but N-tetra-ot-butyl-phenylnitrone (PBN), and deferoxamine (DFX), failed to show protective effects against oxygen radicals. Antagonists of the N-methyl-D-aspartate (NMDA) receptor, D-2-amino-5-phosphonovaleric acid (APV), 7-chlorokynurenic acid (CKA), and MK801 (a non-competitive NMDA antagonist) were also not effective in blocking neurotoxicity induced by glucose oxidase generated oxygen radicals.