• Journal of Food Hygiene and Safety
• /
• v.32 no.5
• /
• pp.443-446
• /
• 2017

This study investigated the physical properties of polymers and antimicrobial activities of organic acids on Listeria monocytogenes to develop hydrogels. ${\kappa}-carrageenan$ (1, 2, and 3%), carboxymethylcellulose (CMC; 1, 3, and 5%), and agar (1.5 and 3%) were mixed with cross-linkers ($Na^+$, $K^+$, $Ca^{2+}$, and $Al^{3+}$) or each other by stirring or heating to form cross-linkage, and their physical properties (hardness, elasticity, and swelling) were measured. The hydrogels formulated with organic acid (1, 3, and 5%) were analyzed by spot assay against L. monocytogenes. ${\kappa}-carrageenan$ formed hydrogels with high hardness without other cross-linkers, but they had low elasticity. The elasticity was improved by mixing with other cross-linkers such as $K^+$ or other polymer, especially in 3% ${\kappa}-carrageenan$. CMC hydrogel was formed by adding cross-linkers $Al^{3+}$, $Na^+$, or $Ca^{2+}$, especially in 5% CMC. Thus, stickiness and swelling for selected hydrogel formulations (two of ${\kappa}-carrageenan$ hydrogels and three of CMC hydrogels) were measured. Among the selected hydrogels, most of them showed appropriate hardness, but only 3% ${\kappa}-carrageenan-contained$ hydrogels maintained their shapes from swelling. Hence, 3% ${\kappa}-carrageenan+0.2%$ KCl and 3% ${\kappa}-carrageenan+1%$ alginate+0.2% KCl+0.2% $CaCl_2$ were selected to be formulated with lactic acid, and showed antilisterial activity. These results indicate that 3% ${\kappa}-carrageenan$ hydrogels formulated with lactic acid can be used to control L. monocytogenes on food surface.

• Clean Technology
• /
• v.11 no.4
• /
• pp.189-194
• /
• 2005

Carboxymethylcellulose(CMC) which is water-soluble fiber was manufactured by mercerization and etherification in the earlier study. Experimental parameters were conversion time for each step, concentration of reagent and temperature. To know the presence of functional group, CMC was analyzed by FT-IR(Fourier Transform Infrared) spectroscopy. Ethanol was recovered using evaporator and purity of ethanol analyzed by GC-MASS was 97% and 83% after mercerization and etherification respectively. For the pilot plant, if CMC is folded by 40 times it showed maximum efficiency. Maximum solubility was obtained when the ratio of NaOH and MCA is 3 : 4.5.

• The Korean Journal of Mycology
• /
• v.24 no.3 s.78
• /
• pp.206-213
• /
• 1996

Talaromyces luteus 2004, a thermophilic mutant of T. luteus 6112 was obtained by mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine. T. luteus 2004 produced thermophilic carboxymethylcellulase (CMCase), and other polysaccharide enzymes: avicellase, xylanase, and ${\beta}-glucosidase$. Induction of CMCase production was shown at the highest level in 3% carboxymethylcellulose (CMC) minimal broth, indicating that CMC could work as an inducer. However, glucose and D-cellobiose showed catabolite repression for CMCase production which was under the control of CMC utilization. Optimal conditions for CMCase activity were at $70^{\circ}C$ and pH 4.0, suggesting that CMCase of T. luteus 2004 was a thermophilic enzyme.

• Journal of the Korean Applied Science and Technology
• /
• v.6 no.1
• /
• pp.31-40
• /
• 1989

Five novel amphoteric surfactants of N-acyloxyethylcarboxybetaine series were synthesized via Schotten-Baumman reaction between five acid chlorides containing 10, 12, 14, 16 and 18 carbon atoms in their N-alkyl groups and dimethylaminoethanol to give the intermediate products, 2-dimethylaminoethylalkanoates(2). Quaternization of these products(2) was permitted to from 2-(acyloxyethyldimethylammonic)- acetates(3), whose structures were identified by elemental analysis, IR spectrophotometry and $^1Hnmr$ spectrometry. The yield of the final products was shown in the range of 77-80% based on the intermediate products. The surface tension of the aqueous solution of (3) was measured, and the critical micelle concentrations (cmc) were shown in the range of $2.1\;{\times}\;10^{-3}\;-\;3.3\;{\times}\;10^{-4}mol/l$, and the surface tension at cmc was 28-36 dyne/cm. Cmc was lowered gradually by the increment of the length of N-alkyl ester containing group. The isoelectric point was shown in the range of 4.44-5.20. It showed a tendency to lean toward the acidic site and its range was broadened as increase of the hydrophobic group length. A linear relationship between log cmc and the number of carbon atoms(N) in the hydrophobic alkyl chain was shown in the relative equation of log cmc=-1.75-0.1N, and the contribution rate of N on the standard free energy change in micellization, ${\bigtriangleup}({\bigtriangleup}G^{\circ}m)/{\bigtriangleup}N$, was calculated as -0.23 RT.

• Korean Chemical Engineering Research
• /
• v.46 no.4
• /
• pp.824-832
• /
• 2008

micellar solution which is comprised of surfactant monomers, monodisperse micelles, and solvent(water) is studied from a statistical-mechanical point of view. The model examined in this article is for the ideal mixture of monomers, micelles, and solvent with the dielectric constant identical to that of solvent, which is an assumption common to continuum models. The model also reflects interactions between monomer and solvent molecule, and also between micelle and solvent molecule. The statistical-mechanical model under consideration yields ln $X_{CMC}=A+BT+C/T+D{\ln}T$ with $X_{CMC}$ being critical mcielle concentration (in mole fraction), being temperature, and A, B, C, D being constants which depend on the properties of the surfactant molecules. The statistical-mechanical model discussed in this article provides a theoretical basis on the thermal dependence of critical micelle concentration

• Journal of the Korean Chemical Society
• /
• v.48 no.3
• /
• pp.236-242
• /
• 2004

The critical micelle concentration (CMC) and the counterion binding constant (B) in a mixed micellar state of the Dodecylpyridinium chloride (DPC) with the Cetyldimethylethylammonium bromide (CDEAB) at 25$^{\circ}C$ in aqueous solutions of n-butanol were determined as a function of ${\alpha}_1$ (the overall mole fraction of DPC) by the use of electric conductivity method. Various thermodynamic parameters (($X_i,\;{\gamma}_i,\;C_i,\;a^M_i,\;{\beta},\;and {\Delta}H_{mix})$were calculated by means of the equations derived from the nonideal mixed micellar model. The effect of n-butanol on the mixed micellization of the DPC/CDEAB mixtures has been also studied by analyzing the measured and calculated thermodynamic parameters (CMC, B 및 $;{\Delta}G_o\;^m$).

• Journal of the Korean Chemical Society
• /
• v.40 no.6
• /
• pp.420-426
• /
• 1996

The critical micelle concentration(CMC) and the counterion binding $constant(\beta)$ at the CMC of the mixtures of Sodium dodecylsulfate(SDS) with Sodium dodecylbenzenesulfonate(DBS) in aqueous solutions have been determined from the concentration dependence of electrical conductance at several temperatures from $15^{\circ}C$ to $35^{\circ}C.$ Thermodynamic parameters(${\Delta}C_p,\;{\Delta}G_m^{\circ},\;{\Delta}H_m^{\circ}$ 및 ${\Delta}S_m^{\circ}$ and ${\Delta}C_p$), associated with the micelle formation of SDS/DBS mixtures, have been estimated from the temperature dependence of CMC and $\beta$ values. The measured values of ${\Delta}G_m^{\circ}\;and\;{\Delta}C_p$ are negative but the values of ${\Delta}S_m/^{\circ}$ are positive in the whole measured temperature region. The significance of these thermodynamic parameters and their relation to the theory of the micelle formation of SDS/DBS mixtures have been also considered.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2004.03a
• /
• pp.453-459
• /
• 2004

An axially staged combustor equipped with an LPP combustion system and CMC liner walls has been investigated for stable combustion and low NOx emissions for the ESPR project. Several fuel injectors were designed and manufactured for the LPP burner, and single sector combustor tests were conducted to evaluate fundamental combustion characteristics such as emissions, instabilities, auto-ignition, and flash back at typical operating conditions from idle to Mn 2.2 cruise. The latest test results showed that the LPP burner had a good potential for the low NOx target. It was also found that the NOx emission level was greatly affected by a distortion in the air flow velocity field upstream of the LPP burner due to the diffuser and fuel feed arm. The CMC material was investigated to apply for the high temperature and low NOx combustor. Annular combustor liner walls were manufactured with the CMC material, and they have been tested at low pressure conditions to evaluate the soundness of the material and the mounting and seal system. This paper reports the latest research activities on the LPP combustion system and CMC liner walls for the ESPR project.

• Applied Biological Chemistry
• /
• v.51 no.1
• /
• pp.6-10
• /
• 2008

This study was carried out to investigate rheological properties of bread dough by adding hydrocolloids such as arabic gum, pectin and carboxyl methyl cellulose (CMC). 0.2% and 0.5% of each hydrocolloid were added to the dough. Farinograph, pH of dough, extensograph, fermometer and amylograph were analyzed. In farinograph, water absorption rate of dough was increased by adding hydrocolloids and the highest water absorption resulting in 70.8% was shown by adding 0.5% of CMC. Dough development time increased but stability decreased. pH of dough was lowered by adding hydrocolloids and pH of dough with 0.5% of pectin was the lowest. In extensograph, resistance of dough decreased but extensibility increased and R/E value lowered. In fermometer, $CO_2$ gas production increased and dough with 0.2% of CMC showed the largest gas production. In amylograph, initial gelatinization temperature increased by $0.5-1.5^{\circ}C$, but temperature for maximum viscosity was lowered by $1-1.5^{\circ}C$ and maximum viscosity was increased.

• Journal of Information Management
• /
• v.30 no.3
• /
• pp.27-43
• /
• 1999

The digital library operated in the environment of computer-mediated-communication offered new successful alternative plans for the field and communication methods of the information services that have been provided by the traditional library and this causes the traditional library to move to the new paradigm. In this situation, the information services of the digital library raised the necessity for the communication channels that would cope actively on the spot and for the extention of information services that would supply an unspecified number of the general public with a considerable extention of information services that neglect time and space. This study looked into the communication channels in general for interactions between the digital library and the users in the environment of computer-mediated-communication and observed patterns of communication chennels that the digital library could supply. For the development of the communication model in the digital library, the study presented the communication model for effective information services.