• Title/Summary/Keyword: Non-enzymatic

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Browning Reaction of Fresh Ginseng (Panax ginseng C.A. Meyer) as Affected by Heating Temperature (가열온도에 따른 수삼의 갈변반응 특성)

  • 이종원;이성계
    • Journal of Ginseng Research
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    • v.19 no.3
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    • pp.249-253
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    • 1995
  • In the browning reaction of Korean ginseng, it appears that enzymatic and non-enzymatic browning reaction occurred in the initial stage of heating fresh ginseng at low temperature, and then non-enzymatic browning reaction followed in the drying period after heating. Activation energy of the browning reaction for red ginseng was about 9.0 kcal/mol. Browning reaction of red ginseng was accede- rated with an increase in steaming time, and a great extent of browning reaction occurred between 60-90 min of steaming at 10$0^{\circ}C$. Browning pigments of red ginseng were mostly water soluble subset.

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MOF-based Sensing Materials for Non-enzymatic Glucose Sensors

  • Jingjing Liu;Xiaoting Zha;Yajie Yang
    • Journal of Electrochemical Science and Technology
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    • v.15 no.1
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    • pp.32-50
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    • 2024
  • Diabetes mellitus is one of the common chronic diseases, seriously threating to human health. The continuous monitoring of blood glucose concentration can effectively prevent diabetic diseases. The sensing performance of glucose non-enzymatic sensors is mainly determined by working electrode materials. Metal-organic frameworks (MOFs) are recognized as promising candidate for glucose sensor application, due to its large surface areas, ordered porous structure and nearly infinite designability. In this review, the sensing performance, research progress and future challenge of non-enzymatic glucose sensors based on MOF-based materials in recent years are presented. We hope that this review would provide valuable technology guidance for high performance non-enzymatic glucose sensors based on MOFs.

Electrochemical Non-Enzymatic Glucose Sensor based on Hexagonal Boron Nitride with Metal-Organic Framework Composite

  • Ranganethan, Suresh;Lee, Sang-Mae;Lee, Jaewon;Chang, Seung-Cheol
    • Journal of Sensor Science and Technology
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    • v.26 no.6
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    • pp.379-385
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    • 2017
  • In this study, an amperometric non-enzymatic glucose sensor was developed on the surface of a glassy carbon electrode by simply drop-casting the synthesized homogeneous suspension of hexagonal boron nitride (h-BN) nanosheets with a copper metal-organic framework (Cu-MOF) composite. Comprehensive analytical methods, including field-emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), cyclic voltammetry, electrochemical impedance spectroscopy, and amperometry, were used to investigate the surface and electrochemical characteristics of the h-BN-Cu-MOF composite. The FE-SEM, FT-IR, and XRD results showed that the h-BN-Cu-MOF composite was formed successfully and exhibited a good porous structure. The electrochemical results showed a sensor sensitivity of $18.1{\mu}A{\mu}M^{-1}cm^{-2}$ with a dynamic linearity range of $10-900{\mu}M$ glucose and a detection limit of $5.5{\mu}M$ glucose with a rapid turnaround time (less than 2 min). Additionally, the developed sensor exhibited satisfactory anti-interference ability against dopamine, ascorbic acid, uric acid, urea, and nitrate, and thus, can be applied to the design and development of non-enzymatic glucose sensors.

The Electrochemical Studies of Non-enzymatic Glucose Sensor on the Nickel Nanoparticle-deposited ITO Electrode (ITO 전극 위에 고정된 니켈 나노 입자를 이용한 무효소 혈당센서에 관한 전기화학적인 연구)

  • Oh, In-Don;Kim, Samantha;Choi, Young-Bong
    • Journal of the Korean Electrochemical Society
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    • v.17 no.3
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    • pp.164-171
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    • 2014
  • A highly sensitive and selective non-enzymatic glucose sensor has gained great attention because of simple signal transformation, low-cost, easily handling, and confirming the blood glucose as the representative technology. Until now, glucose sensor has been developed by the immobilization of glucose oxidase (GOx) on the surface of electrodes. However although GOx is quite stable compared with other enzymes, the enzyme-based biosensors are still impacted by various environment factors such as temperature, pH value, humidity, and toxic chemicals. Non-enzymatic sensor for direct detecting glucose is an attractive alternative device to overcome the above drawbacks of enzymatic sensor. Many efforts have been tried for the development of non-enzymatic sensors using various transition metals (Pt, Au, Cu, Ni, etc.), metal alloys (Pt-Pb, Pt-Au, Ni-Pd, etc.), metal oxides, carbon nanotubes and graphene. In this paper, we show that Ni-based nano-particles (NiNPs) exhibit remarkably catalyzing capability for glucose originating from the redox couple of $Ni(OH)_2/NiOOH$ on the surface of ITO electrode in alkaline medium. But, these non-enzymatic sensors are nonselective toward oxidizable species such as ascorbic acid the physiological fluid. So, the anionic polymer was coated on NiNPs electrode preventing the interferences. The oxidation of glucose was highly catalyzed by NiNPs. The catalytically anodic currents were linearly increased in proportion to the glucose concentration over the 0~6.15 mM range at 650 mV versus Ag/AgCl.

Antioxidant Activity of Aqueous Extract of Coscinium fenestratum in STZ-Nicotinamide Induced Diabetic Rats

  • Punitha, I.S.R.;Bhat, Nalini;Rajendran, K.;Shirwaikar, Arun;Shirwaikar, Annie
    • Natural Product Sciences
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    • v.11 no.3
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    • pp.155-159
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    • 2005
  • The aqueous extract of Coscinium fenestratum was studied for its antioxidant status in STZ-nicotinamide induced type 2 diabetic rats at two dose levels of 250 mg/kg and 500 mg/kg. At the end of the experimental period, diabetic rats treated with aqueous extract at both dose levels showed a significant increase in the levels of enzymatic antioxidants such as glutathione peroxidase, glutathione synthetase, peroxidase, superoxide dismutase and catalase as compared to the untreated control. Similarly, a significant increase was also observed in the levels of the non enzymatic antioxidants ceruloplasmin, ascorbic acid and tocopherol. The results suggest that the aqueous stem extract of C. fenestratum prevents type 2 diabetes mellitus induced oxidative stress.

Effects of Butanol Extract of Aralia elata on Lipid Peroxidation (두릅나무 부탄올 추출물이 지질 과산화에 미치는 영향)

  • 서보권;정연봉;김용규;신옥진;이종철
    • YAKHAK HOEJI
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    • v.37 no.3
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    • pp.270-277
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    • 1993
  • It is well known that lipidperoxide, formed in vivo, induced the denaturation of enzyme and destruction of cell membrane to acute injury of tissue. Aralia elata have physiological activates, the improvement of lipid metabolism, antidiabetic activity etc., which was thought to have the relationship to lipid peroxidation. The anti-lipidperoxidative effect of Aralia elata have not yet established. In this study, we examined the anti-lipidperoxidative effects of Aralia elata (Butanol fraction) on CCI$_{4}$ induced lipidperoxidation in rats, and elucidated the anti-lipidperoxidative mechanism. In rat liver homogenate intoxicated with CCI$_{4}$ (0.5 ml/100g), BuOH fraction of Aralia elata (80 mg/Kg/day) exhibited 85.41% anti-lipidperoxidative effect but in serum 69.63% inhibitory effects, respectively. In mitochondrial and microsomal fraction showed inhibition of 55.85% and 69.30%, respectively. In order to elucidate the mechanism of anti-lipidperoxidation effects of Aralia elata, enzymatic (NADPH dependent) and non-enzymatic (Ascorbic acid catalyzed) reaction, in vitro, were performed. In enzymatic reation, Aralia elata exhibited 59.43% anti-lipidperoxidation effects, but in non-enzymatic reaction exhibited 43.27% inhibition. Therefore, it is noteworthy that antioxidative power of them may mainly results from the inhibition by enzymatic reaction.

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Control of Enzymatic Degradability of Biodegradable Polylactide by Blending with Non-degradable Polymers (비 분해성고분자와 블렌드를 이용한 생분해성 폴리유산의 효소분해속도 조절)

  • Jang, Seong-Ho;Park, Sang-Bo;Lee, Won-Ki
    • Journal of Environmental Science International
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    • v.19 no.9
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    • pp.1161-1167
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    • 2010
  • The effects of addition of non degradable polymers, polystyrene (PS) and poly(methyl methacrylate) (PMMA) on the rate of enzymatic degradation of biodegradable poly(l-lactide) (PLLA) have been studied in term of surface structure. Since a component in multicomponent polymeric system has shown surface enrichment, PS and PMMA which have lower surface energy than PLLA were selected as a minor blend component (5 wt%). Enzymatic degradation was carried out at $37^{\circ}C$ and pH 8.5 in the aqueous solution of Proteinase K. Two blend systems, partially miscible (PS/PLLA) and immiscible (PMMA/PLLA), showed the surface enrichment of 4 and 2 times of PS and PMMA, respectively. From the weight loss profile data, the slow degradation rate of both blend films was observed. This indicates that PS or PMMA domains which exist at surface act as a retardant of enzymatic attack.

The Production of Alcohol from Municipal Waste(II) - The Effects of Physical or Chemical Treatment on the Enzymatic Hydrolysis of Waste Paper - (도시 폐기물로부터 알코올 생산 (II) - 물리적, 화학적 전처리된 폐지의 효소가수분해 조건 검토 -)

  • Lim, Bu-Kug;Yang, Jae-Kyung;Lee, Jong-Yoon
    • Journal of the Korean Wood Science and Technology
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    • v.25 no.1
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    • pp.65-70
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    • 1997
  • The effects on the enzymatic hydrolysis of waste paper treated with physical or chemical treatment were investigated. To gain the higher saccharification rate, physical or chemical treatment are necessary in enzymatic conversion process of waste paper. The major deterrents to the effective utilization of waste paper for enzymatic conversion process are phenolic compounds, cellulose crystallinity and coating materials. In the enzymatic hydrolysis of waste paper, the deterrents through enzymatic conversion process can be eliminated by the physical or chemical treatment. This study was performed to obtain the optimal condition for enzymatic conversion process of non-treated waste paper and to review effects on enzymatic conversion process of waste paper treated with physical or chemical methods. In the aspect of saccharification rate, waste paper treated with 1.5% sodium hypochlorite was the most effective and in physical treatment methods, multi-stage treatment(autohydrolysis+refining treatment) was more effective than the other physical treatment.

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Control of Enzymatic Degradability of Microbial Polyester by Surface Modification (표면 개질을 통한 미생물합성 폴리에스테르의 효소분해속도 조절)

  • 이원기
    • Journal of Environmental Science International
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    • v.11 no.12
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    • pp.1315-1320
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    • 2002
  • Since the enzymatic degradation of microbial poly[(R)-3-hydroxybutyrate-co-3-hydroxyvalerate] (P(3HB-co-3HV)) initially occurs by a surface erosion process, a degradation behavior could be controlled by the change of surface property. In order to control the rate of enzymatic degradation, plasma gas discharge and blending techniques were used to modify the surface of microbial P(3HB-co-3HV). The surface hydrophobic property of P(3HB-co-3HV) film was introduced by CF$_3$H plasma exposure. Also, the addition of small amount of polystyrene as a non-degradable polymer with lower surface energy to P(3HB-co-3HV) has been studied. The enzymatic degradation was carried out at 37 $^{\circ}C$ in 0.1 M potassium phosphate buffer (pH 7.4) in the presence of an extracellular PHB depolymerase purified from Alcaligenes facalis T1. Both results showed the significant retardation of enzymatic erosion due to the hydrophobicity and the enzyme inactivity of the fluorinated- and PS-enriched surface layers.

Antioxidant Activities of Cedrela sinensis Hydrolysates Prepared Using Various Enzymes (효소 종류에 따른 참죽 추출물의 산화방지 효과)

  • Oh, Min Hui;Jang, Hye Lim;Lim, Ye Jin;Yoon, Kyung Young
    • Korean Journal of Food Science and Technology
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    • v.47 no.4
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    • pp.413-418
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    • 2015
  • This study was conducted to analyze the functional component contents and antioxidant activities of Cedrela sinensis extracts hydrolyzed using four different enzymes. The yield of Viscozyme extract was the highest among the samples, and all enzymatic extracts, except for the commercial glucoamylase (AMG) extract, had significantly higher total polyphenol and flavonoids contents compared to the non-enzymatic extract (p<0.05). Viscozyme extract showed the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and $Fe^{2+}$ chelating ability among the samples. All enzymatic extracts showed high>90% 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging activity, and there was no significant difference between the enzymatic and non-enzymatic extracts. The reducing power of the extracts using Shearzyme or Viscozyme was significantly higher than that of the other samples (p<0.05). Therefore, the results indicated that all enzymatic extracts (especially Viscozyme extract), except for the AMG extract, showed high antioxidant activity compared to the non-enzymatic extract. These result suggested that the enzymatic extracts of C. sinensis can be used in functional foods.