• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.9 no.1
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• pp.33-54
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• 2003

The aim of this study was to develop a model that could be used in the design of modified atmosphere packaging (MAP) for peaches. Respiratory data at 5, 10, $20^{\circ}C$ for peaches were gathered and altered for create useful respiration model. Packaging materials were conventional low density polyethylene and polypropylene with anti-fog, and anti-fungi treatments, and thickness was $30{\mu}m$ and $50{\mu}m$ each. Permeability tests were performed to find their oxygen, carbon dioxide, water vapor transmission rate as increases in temperature. Test results were then converted to logarithm format for MAP modeling. The maximum rate of oxygen uptake increased with increasing temperature. Optimum gas composition in the package system for fruits were set according to literature and upper or lower limits of oxygen and dioxide established. To predict gas composition at certain storage time, weight of fruits, film thickness, film type, and other variables, respiration rate was studied at various storage conditions. The results of tests were used to calculate Cameron's model and converted to a cubic estimation equation. The validity of the model was tested experimentally by observing actual atmospheric changes inside packages. This result of study may be useful for designing dynamic gas exchange MAP systems for similar agricultural products.

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.855-861
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• 1998

Composite films based on ${\kappa}-carrageenan$ and chitosan were prepared, and tensile strength (TS), elongation (E), and water vapor permeability (WVP) of the films were measured. The molecular weight of ${\kappa}-carrageenan$ and chitosan was measured by a light-scattering instrument and was $5.1{\times}10^5,{\;}and{\;}1.71{\times}10^5$, respectively. TS of ${\kappa}-carrageenan$ and chitosan free film was 30.2 MPa and 21.0 MPa, respectively. TS of composite film was not related to the amount of the ascorbic acid. E of composite film was lower than those of the free films of ${\kappa}-carrageenan$ and chitosan. WVP of composite film was lower than that of chitosan film and was similar to WVP of ${\kappa}-carrageenan$ film.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.5
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• pp.664-668
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• 1999

The extracting conditions of alginates from sea tangle were evaluated by measuring water vapor permeability (WVP) and tensile properties of alginate film to obtain basic data of making an edible and biodegradable film. The alginates were extracted with $1\%,\;3\%$ and $5\%$ sodium carbonate ($Na_2CO_3$) for 1, 3, 5 and 10 hours, and the alginate film was made with various plasticizers. The higher concentration of $Na_2CO_3$ solution showed the lower viscosity and polymerization degree of alginate and the film prepared with alginates having low viscosity showed the higher WVP. The extracting hours had little effect on the WVP and the elongation of alginate film, but the polymerization degree of alginates directly affected the tensile strength of the film. The addition of sorbitol and polyethylene glycol as a plasticizer lowered the WVPs and the elongation of alginate film.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.9
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• pp.1251-1255
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• 2006

To improve the water resistance and physical properties of soy protein isolate (SPI)-coated paper, effects of concentrations of soy protein isolate and plasticizer were examined. Physical properties such as elongation strength (ES), elongation rate (E), water vapor permeability (WVP), and water solubility (WS) were evaluated. The film made from 5% soy protein isolate (SPI) and 40% glycerol (plasticizer) suggested a good application for a film preparation. SPI coated paper showed the highest ES (21.62 MPa) and the lowest WVP $(2.06ng{\cdot}m/m^2{\cdot}s{\cdot}Pa)$ and WS (1.17%). This study suggested that soy protein isolate (SPI) can be used as a coating material for the coated paper to improve the water resistance.

• Journal of Microbiology and Biotechnology
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• v.29 no.9
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• pp.1401-1411
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• 2019

Mycobacterial cell walls comprise thick and diverse lipids and glycolipids that act as a permeability barrier to antibiotics or other chemical agents. The use of OH radicals from a non-thermal plasma jet (NTPJ) for the inactivation of mycobacteria in aqueous solution was adopted as a novel approach. Addition of water vapor in a nitrogen plasma jet generated OH radicals, which converted to hydrogen peroxide ($H_2O_2$) that inactivated non-pathogenic Mycobacterium smegmatis and pathogenic Mycobacterium tuberculosis H37Rv. A stable plasma plume was obtained from a nitrogen plasma jet with 1.91 W of power, killing Escherichia coli and mycobacteria effectively, whereas addition of catalase decreased the effects of the former. Mycobacteria were more resistant than E. coli to NTPJ treatment. Plasma treatment enhanced intracellular ROS production and upregulation of genes related to ROS stress responses (thiolrelated oxidoreductases, such as SseA and DoxX, and ferric uptake regulator furA). Morphological changes of M. smegmatis and M. tuberculosis H37Rv were observed after 5 min treatment with $N_2+H_2O$ plasma, but not of pre-incubated sample with catalase. This finding indicates that the bactericidal efficacy of NTPJ is related to the toxicity of OH and $H_2O_2$ radicals in cells. Therefore, our study suggests that NTPJ treatment may effectively control pulmonary infections caused by M. tuberculosis and nontuberculous mycobacteria (NTM) such as M. avium or M. abscessus in water.

• Korean Journal of Food Science and Technology
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• v.13 no.4
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• pp.314-318
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• 1981

In order to improve the storage stability of spray and freeze dried red ginseng extract powder packed in a bottle, the water vapor permeability of Al-foil laminate paper used for cap closure and shelf life of those products on various storage temperatures and relative humidities were investigated. The thickness of the laminate paper was $93{\pm}3\:{\mu}m$ and its physical properties were equal to standard of ASTM (B-377-66) The absorption rate of the freeze dried powder was 2-6 times greater than that of the spray dried powder at $37^{\circ}C$. Therefore it was considered that the laminate could be used for cap closures for the spray dried powder but unsuitable for the freeze dried powder. The shelf life of the spray dried powder was longer than that of the freeze-dried powder at $37^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.43 no.1
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• pp.30-38
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• 2011

Effects of depolymerization treatments of a carbohydrase mixture (CM), ultrasound, and irradiation on the physical properties of defatted mustard meal-based edible films (DMM films) were investigated. DMM hydrocolloids were added to CM (0.42% (w/w solution)), treated by ultrasound (500-700 W, 10-30 min) or ${\gamma}$-ray (40-100 kGy) to prepare film-forming solutions. Films were formed by drying. The CM treatment at 0.42% (w/w), pH 5.5, and 40-$50^{\circ}C$ with a 0.5 hr incubation time resulted in the highest colloidal stability in the film-forming solution. The depolymerization treatments did not dramatically change the water vapor permeability of the films. The solubility of the film decreased up to 53.1% by the CM treatment. The ultrasound treatment (700 W-30 min) decreased tensile strength and elongation. The ultrasound treatment (600 W-20 min) resulted in more compact and uniform structures of the films. Flavor profiles were differentiated by the power level and the time of the ultrasound treatment.

• Journal of Applied Biological Chemistry
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• v.58 no.2
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• pp.145-151
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• 2015

Corn fiber protein (CFP) was extracted from corn wet-milling by-product, corn fiber. CFP films containing various plasticizers and cross-linking agents were prepared and their mechanical properties were determined. Among the plasticizers and cross-linking agents used in this study, the CFP film containing 2 g fructose and 0.03% cinnamaldehyde had the most appropriate physical property. In addition, the CFP films containing green tea extract (GTE) were prepared by incorporating different amounts (0, 0.5, 1.0, 1.5%) of GTE into the film-forming solution. Tensile strength, film solubility, and opacity of the CFP films increased with the addition of GTE, whereas elongation and water vapor permeability of the CFP/GTE films decreased compared to those of the control. The antioxidant activity of the CFP/GTE film was determined in terms of 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity. As a result, antioxidant activity of the films increased with increasing GTE concentration. Furthermore, antimicrobial activity against Escherichia coli O157:H7, Listeria monocytogenes, and Staphylococcus aureus increased with increasing GTE concentration. These results indicate that the incorporation of GTE could enhance antioxidant and antimicrobial activities of the CFP films.

• Conservation Science in Museum
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• v.16
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• pp.96-113
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• 2015

High-barrier films are used to store cultural heritage objects in a safe environment sealed from oxygen and moisture. One of the high-barrier films use populary E manufactured by Japanese company M from the 1990's. However, this product has stayed in wide use, due to dearth of research on related subjects - including studies comparing it with other similar products-, in spite of the fact that high price information about its characteristics and environmental conditions is largely lacking. This study examines the characteristics of a number of high-barrier films with the goal to establish environmental standards for safer conservation of cultural heritage objects. E by the Japanese manufacturer M is compared with four other films; an electronics packaging films by a Korean firm, a film specially produced for the purposes of experiment in this study and a zipper bag-type film. Experiments were performed to compare the properties and gas blocking ability of the films by looking at their cross-section and measuring the thickness, tensile strength, elongation, absorbance of UV and visible light, yellowing and the permeability for oxygen and vapor. Based on these experiments, there are observed changes under different environmental conditions and depending on the length of use through temparature and humidification reproucing test. The results showed that while the high-barrier film by the Korean manufacturer was suitable for use as a packaging material for cultural heritage objects, the zipper bag-type film (P) was ill-adapted for this purpose. Based on the experiments reproducing the real-world environment, the length of useful life was also determined for each.

• Korean Journal of Organic Agriculture
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• v.23 no.1
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• pp.91-101
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• 2015

'Chuhwangbae' pears (Pyrus pyrifolia Nakai) were investigated on how types of paper bag and harvesting dates influenced on skin blackening before harvest as well as fruit quality after harvest. Experiments included four different types of paper bags (NP/YP, GP/YP, NP/BP, and NP/RP) and five different harvesting dates [160, 170, 180, 190, and 200 days after full bloom (DAFB)]. NP/YP and GP/YP indicated for newspaper- and gray paper-outer bag, respectively, with yellow paper-inner bag of the both. NP/BP and NP/RP indicated for newspaper-outer bag of the both with black paper- and red paper-inner bag, respectively. The NP/YP (newspaper/yellow paper) showed high absorbance and air and water vapor permeability in the bags, while the NP/RP (newspaper/red paper) resulted in poor physical properties in the bags. Fruit enclosed with NP/YP resulted in the absence of skin blackening, but fruit with NP/RP bags had the highest skin blackening (12.7%). Occurrence of skin blackening was concentrated on the middle and calyx end-part of fruit region. NP/RP bag treatment was likely to increase fruit weight, firmness, titratable acidity, and fruit surface color. Harvest at high relative humidity in air increased skin blackening of fruit. Later fruit harvest, such as 190 and 200 DAFB, increased skin blackening, fruit weight, and sugar content while decreasing fruit firmness and titratable acidity.