• Title/Summary/Keyword: chitosan

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Chitinase Activity and Textural Property of Leek Added Kimchi During Fermentation (부추첨가 김치의 발효과정 중 chitinase 활성과 조직감)

  • 김유경;이귀주
    • Korean journal of food and cookery science
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    • v.15 no.2
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    • pp.102-107
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    • 1999
  • Several ingredients of kimchi including chinese cabbage, garlic, leek, big green onion, and small green onion were assayed for their chitinase activities. Kimchi with various leek contents (4, 8, 12%) were fermented at 15$^{\circ}C$ for 9 days and the chitinase (EC 3.2.1.14) activity and textural properties were determined. The chitinase activity of the ingredients was in the order of garlic>leek>small green onion>chinese cabbage>big green onion. During fermentation, the chitinase activity of kimchi juice appeared more prominent than that of kimchr tissue, however, it was decreased in all kimchi samples among which the control sample showed a remarkable drop. The activity of chitinase in kimchi tissue increased until 3rd or 5th day of fermentation and then decreased. The puncture force of all kimchi samples decreased and those of leek-added kimchi were higher than those of control. The above results suggested that the addition of leek for kimchi preparation could contribute to the improvement of textural qualities of kimchi due to chitinase activities of leek during fermentation.

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A Study on the Electrochemical Characteristics of Biosensor with HRP Enzyme Immobilized on SPCE (SPCE에 HRP 효소가 고정화된 바이오센서의 전기화학적 특성에 관한 연구)

  • Han, Kyoung Ho;Lee, Dae Hyun;Yoon, Do Young;Choi, Sangil
    • Journal of the Korean Electrochemical Society
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    • v.23 no.3
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    • pp.73-80
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    • 2020
  • Fenton oxidation method using hydrogen peroxide is an eco-friendly oxidation method used in water treatment and soil restoration. When removing pollutants by this method, it is quite important to properly regulate the concentration of hydrogen peroxide according to the concentration of the contaminants. In this study, electrochemical biosensors using HRP (horseradish peroxidase) enzymes were manufactured and studies were conducted on the activity of enzymes and the detection characteristics of hydrogen peroxide. HRP were electro deposited with chitosan and AuNP on the working electrode surface of the SPCE (Screen Printed Carbon Electrode). Then, the fixation of enzymes was confirmed using the cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The activity of HRP enzymes was also identified from chronoamperometry (CA) and UV spectroscopy. After immersing the biosensor in PBS solution the current generated from electrodes by titrating hydrogen peroxide was measured from CA analysis. The generated current increased linearly for the concentration of hydrogen peroxide, and a calibration curve was derived that could predict the concentration of hydrogen peroxide from the current.

Quality Changes of Satsuma Mandarin during Storage by Storage Warehouse (저장고 형태에 따른 온주밀감의 저장 중 품질변화)

  • 김성학;임자훈;고정삼
    • Food Science and Preservation
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    • v.9 no.2
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    • pp.131-136
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    • 2002
  • Quality changes of satsuma mandarin (Citrus unshiu Marc. var. miyagawa) during storage by storage warehouse were investigated. Citrus were treated with 2000-folds diluted iminoctadime-triacetate solution and 1.5% chitosan with 0.5% CaCl$_2$ solution, and were at 30$\^{C}$ for 24 hr before storage. The citrus of about 12kg/26L plastic container were stored at room temperature, and at 4$\^{C}$ with 87% relative humidity. Decay ratio of citrus with precise temperature and humidity control were lower than the others during storage. Penicillium italicum Monilia candida Alternara citri, Mucor hiemalis, Phomopsis citri Botrytis cinerea, Phoma citricarpa Clomererella cingulata, Penicillium digitatum were identified as putrefactive microorganisms in citrus storage. Weight loss, moisture content of peel and flesh were decreased slowly during storage. 24% of original acid content were decreased at room temperature on 120 days storage, compared to 15∼18% loss on cold storage. Total sugar of citrus was decreased rapidly after 90 days, and vitamin C content were also decreased rapidly after 60 days during storage.

Tumoral Accumulation of Long-Circulating, Self-Assembled Nanoparticles and Its Visualization by Gamma Scintigraphy

  • Cho, Yong-Woo;Kim, Yoo-Shin;Kim, In-San;Park, Rang-Woon;Oh, Seung-Jun;Moon, Dae-Hyuk;Kim, Sang-Yoon;Kwon, Ick-Chan
    • Macromolecular Research
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    • v.16 no.1
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    • pp.15-20
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    • 2008
  • The enhanced permeability and retention (EPR) effect is used extensively for the passive targeting of many macromolecular drugs for tumors. Indeed, the EPR concept has been a gold standard in polymeric anticancer drug delivery systems. This study investigated the tumoral distribution of self-assembled nanoparticles based on the EPR effect using fluorescein and radio-labeled nanoparticles. Self-assembled nanoparticles were prepared from amphiphilic chitosan derivatives, and their tissue distribution was examined in tumor-bearing mice. The size of the nanoparticles was controlled to be 330 run, which is a size suited for opening between the defective endothelial cells in tumors. The long-circulating polymer nanoparticles were allowed to gradually accumulate in the tumors for 11 days. The amount of nanoparticles accumulated in the tumors was remarkably augmented from 3.4%ID/g tissue at 1 day to 25.9%ID/g tissue at 11 days after i.v. administration. The self-assembled nanoparticles were sustained at a high level throughout the 14 day experimental period, indicating their long systemic retention in the blood circulation. The ${\gamma}$-images provided clear evidence of selective tumor localization of the $^{131}I$-labeled nanoparticles. Confocal microscopy revealed the fluorescein-labeled nanoparticles to be preferentially localized in the perivascular regions, suggesting their extravasation to the tumors through the hyperpermeable angiogenic tumor vasculature. This highly selective tumoral accumulation of nanoparticles was attributed to the leakiness of the blood vessels in the tumors and their long residence time in the blood circulation.

Effect of Skim Milk-Alginate Beads on Survival Rate of Bifidobacteria

  • Yu, Won-Kyu;Yim, Tae-Bin;Lee, Ki-Yong;Heo, Tae-Ryeon
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.6 no.2
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    • pp.133-138
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    • 2001
  • In this study, an attempt was made to increase the survival rate of bifidobacteria entrapped in alginate in the gastrointestinal tract, and to investigate the potential industrial applications, for example lyophilized capsules and yogurt. First, the protective effect of various food additives on bifidobacterial survivability was determined after exposure to simulated gastric juices and bile salts. The additives used in this study were skim milk (SM), polydextrose (PD), soy fiber (SF), yeast extract (YE), chitosan (CS), $\kappa$-carageenan ($\kappa$-C) and whey, which were added at 0.6% concentration (w/v) to 3% alginate-bifidobacterial solution. In the simulated gastric juices and bile salts, the protective effect of 0.6% skim milk-3% alginate (SM-A) beads on the survival rate of bifidobacteria proved to be higher than the other additives. Second, the hydrogen ion permeation was detected through SM-A vessel without bifidobacterial cells at different SM concentrations (0.2%, 0.4%, 0.6%, 0.8%, and 1.0%). There were no differences in terms of the pH decrease in SM-A vessels at 0.6%, 0.8%, and 1.0% (w/v) SM concentrations. The survival rate of bifidobacteria in SM-A beads would appear to be related to the SM buffering capacity against hydrogen ions and its tendency to reduce the pore size of bead. In this experiment, the survival rate of bifidobacteria entrapped in beads containing 0.6% SM showed the highest viability after exposure to simulated gastric juices for 3h, thereby indicating that 0.6% SM is the optimum concentration fir 3% alginate bead preparation. Third, the effect of SM-A beads on the freeze-drying and yogurt storage for 10 days was investigated. SM-A beads were found to be more efficient for freeze drying and yogurt storage than untrapped cells and the alginate bead. Consequently, the survival rate of bifidobacteria entrapped in SM-A beads was increased in simulated gastric juices, bile salts and probiotic products, such as lyophilized capsules and yogurt, SM-A beads can be expected to produce high value probiotic products.

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The Esterification of Acetyltyrosine by $\alpha$-Chymotrypsin in EtOH/Water Mixture (에탄올 내에서 $\alpha$-Chymotrypsin에 의한 Acetyltyrosine의 에스테르화 반응)

  • 전유진;김세권
    • KSBB Journal
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    • v.9 no.3
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    • pp.312-318
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    • 1994
  • The esterification of Ac-Tyr-OH was carried out in one-phase system containing ethanol by ${\alpha}$-chymotrypsin. The results of the esterification reaction are as follows. Chitin-${\alpha}$-chymotrypsin complex was found to be an effective catalyst for the esterlfication of Ac-Tyr-OH in ethanol organic solvent. The optimal conditions for the esterification were chitn/${\alpha}$-chymotrypsin ratio, 20(w/w); reaction temp., $35^{\circ}C$; reaction pH, 8.0; reaction time, 24 hrs. Also, addition of chitin in water/water-miscible organic solvent was effective for the stability of the enzyme. The esterification yield, Km and Vmax under optimal conditions were 93%, 3.093mM and 1.088mM/mg/hr, respectively.

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Single-Protein Molecular Interactions on Polymer-Modified Glass Substrates for Nanoarray Chip Application Using Dual-Color TIRFM

  • Kim, Dae-Kwang;Lee, Hee-Gu;Jung, Hyung-Il;Kang, Seong-Ho
    • Bulletin of the Korean Chemical Society
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    • v.28 no.5
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    • pp.783-790
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    • 2007
  • The immobilization of proteins and their molecular interactions on various polymer-modified glass substrates [i.e. 3-aminopropyltriethoxysilane (APTS), 3-glycidoxypropyltrimethoxysilane (GPTS), poly (ethylene glycol) diacrylate (PEG-DA), chitosan (CHI), glutaraldehyde (GA), 3-(trichlorosilyl)propyl methacrylate (TPM), 3'-mercaptopropyltrimethoxysilane (MPTMS), glycidyl methacrylate (GMA) and poly-l-lysine (PL).] for potential applications in a nanoarray protein chip at the single-molecule level was evaluated using prismtype dual-color total internal reflection fluorescence microscopy (dual-color TIRFM). A dual-color TIRF microscope, which contained two individual laser beams and a single high-sensitivity camera, was used for the rapid and simultaneous dual-color detection of the interactions and colocalization of different proteins labeled with different fluorescent dyes such as Alexa Fluor® 488, Qdot® 525 and Alexa Fluor® 633. Most of the polymer-modified glass substrates showed good stability and a relative high signal-to-noise (S/N) ratio over a 40-day period after making the substrates. The GPTS/CHI/GA-modified glass substrate showed a 13.5-56.3% higher relative S/N ratio than the other substrates. 1% Top-Block in 10 mM phosphate buffered saline (pH 7.4) showed a 99.2% increase in the blocking effect of non-specific adsorption. These results show that dual-color TIRFM is a powerful methodology for detecting proteins at the single-molecule level with potential applications in nanoarray chips or nano-biosensors.

Direct Electrochemistry and Electrocatalysis of Myoglobin with CoMoO4 Nanorods Modified Carbon Ionic Liquid Electrode

  • Zhao, Zengying;Cao, Lili;Hu, Anhui;Zhang, Weili;Ju, Xiaomei;Zhang, Yuanyuan;Sun, Wei
    • Bulletin of the Korean Chemical Society
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    • v.34 no.2
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    • pp.475-481
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    • 2013
  • By using ionic liquid 1-hexylpyridinium hexafluorophosphate ($HPPF_6$) based carbon ionic liquid electrode (CILE) as the substrate electrode, a $CoMoO_4$ nanorods and myoglobin (Mb) composite was casted on the surface of CILE with chitosan (CTS) as the film forming material to obtain the modified electrode (CTS/$CoMoO_4$-Mb/CILE). Spectroscopic results indicated that Mb retained its native structures without any conformational changes after mixed with $CoMoO_4$ nanorods and CTS. Electrochemical behaviors of Mb on the electrode were carefully investigated by cyclic voltammetry with a pair of well-defined redox peaks from the heme Fe(III)/Fe(II) redox center of Mb appeared, which indicated that direct electron transfer between Mb and CILE was realized. Electrochemical parameters such as the electron transfer number (n), charge transfer coefficient (${\alpha}$) and electron transfer rate constant ($k_s$) were estimated by cyclic voltammetry with the results as 1.09, 0.53 and 1.16 $s^{-1}$, respectively. The Mb modified electrode showed good electrocatalytic ability toward the reduction of trichloroacetic acid in the concentration range from 0.1 to 32.0 mmol $L^{-1}$ with the detection limit as 0.036 mmol $L^{-1}$ ($3{\sigma}$), and the reduction of $H_2O_2$ in the concentration range from 0.12 to 397.0 ${\mu}mol\;L^{-1}$ with the detection limit as 0.0426 ${\mu}mol\;L^{-1}$ ($3{\sigma}$).

Membrane Application of Polymer/Layered Silicate Nanocomposite (고분자/층상실리케이트 나노복합체의 분리막에의 응용)

  • Park, Ji-Soon;Rhim, Ji-Won;Goo, Hyung-Seo;Kim, In-Ho;Nam, Sang-Yong
    • Membrane Journal
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    • v.15 no.4
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    • pp.255-271
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    • 2005
  • polymer/layered silicate nanocomposite (PLSNs) is new type of materials, based on clays usually rendered hydrophobic through ionic exchange of the sodium interlayer cation with an onium cation. It could be prepared via various synthetic routes comprising exfoliation adsorption, in situ intercalative polymerization and melt intercalation. The whole range of polymer is used, i.e. thermoplastics, thermosets and elastomers as a matrix. Two types of structure may be obtained, namely intercalated nanocomposites where the polymer chains are sandwiched in between silicate layers and exfolicate nanocomposites where the separated, individual silicate layers are more or less uniformly dispersed in the polymer matrix. This new family of materials exhibits enhanced properties at very low filer level, usually inferior to 5wt$\%$, such as increased mechanical properties, increase in thermal stability and gas barrier properties and good flame retardancy. Gas permeability through the PLSNs films decreased due to increased tortuosity made by intercalation or exfoliation of clay in polymer.

Cloning and Expression of Thermostable Chitosanase Gene from Bacillus sp. KFB-C108

  • Yoon, Ho-Geun;Kim, Hee-Yun;Kim, Hye-Kyung;Kim, Kyung-Hyun;Hwang, Han-Joon;Cho, Hong-Yon
    • Journal of Microbiology and Biotechnology
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    • v.9 no.5
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    • pp.631-636
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    • 1999
  • The thermostable endo-chitosanase gene from the isolated strain Bacillus sp. KFB-C108 was identified on the basis of a phylogenetic analysis of the 16S rRNA gene sequence, and was cloned into plasmid pUCl8 using E. coli $DH5\alpha$ as the host strain. Positive clones carrying recombinant plasmids (pKCHO I and pKCHO II) containing chitosanase activity were selected using the direct activity staining method. Detailed physical maps showed the two plasmid inserts were identical except that the KCHO II insert (2.6 kb) was 1.8 kb smaller than that of the KCHO I. The recombinant plasmids were analyzed to determine the essential region for chitosanase activity, and a 1.3-kb fragment (KCHO-6) was subcloned into pTrc99A using the EcoRI and BamHI sites to construct pTrc99A/KCHO-6(pTrEB13). The resulting plasmid exerted high chitosanase activity upon transformation of E. coli $DH5{\alpha}cells$, overproducing about 20 times more in the cloned cells than in the wild-type cells. The cloned chitosanase protein exhibited the same molecular weight and catalytic activity similar to those of Bacillus sp. KFB-C108. The cloned enzyme was an endo-type that produced a chitosan tetramer as the major reaction product; however, it produced no monomers or dimers.

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