• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.24 no.1
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• pp.27-34
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• 2018

In this work, nano ZnO was introduced into low density poly ethylene (LDPE) composites films with various contents (0, 0.5, 1.0, 3.0 and 5.0 wt%) by melt-extrusion. Their basic properties such as crystallinity, chemical bonds and surface morphology were examined by XRD, FTIR and SEM. XRD patterns and FTIR peaks intensity were increased in proportion to the ZnO contents. SEM images showed well dispersed nano ZnO in LDPE composite films. Antimicrobial functionality of LDPE-nano ZnO composite films was also studied and the presence of nano ZnO resulted in significant improvement of antimicrobial functionality compared to the pure LDPE film. To evaluate influence of nano ZnO on LDPE properties required as packaging material, thermal, mechanical, gas barrier and optical properties of LDPE-nano ZnO composite films were characterized with various analytical techniques including TGA, UTM, OTR, WVTR and UV-Vis spectroscopy. As a result, except optical and mechanical properties of LDPE, no significant effects were found in other properties. Opacity of pure LDPE was greatly increased with increasing concentration of nano ZnO and tensile strength was also improved at 0.5wt% ZnO content.

• Korean Journal of Food Science and Technology
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• v.30 no.5
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• pp.1140-1145
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• 1998

Low density polyethylene (LDPE) films incorporated with 1% antimicrobial agents of Rheum palmatum extract, Coptis chinensis extract, and Ag-substituted inorganic zirconium matrix, were applied to modified atmosphere packaging of 200 g fresh strawberries. Plain LDPE film package, PVC wrap and perforative pinhole package of the film impregnated with 1% Rheum palmatum extract were also constructed for comparative purpose. All the packages were stored for 13 days at $5^{\circ}C$ and measured in package atmosphere, microbial count and quality attributes of the strawberry fruits. The antimicrobial LDPE films retarded the growth in total aerobic bacteria, lactic acid bacteria and yeast on the fruits, and resulted in significantly lower decay. The degrees of reduced microbial growth and fruit decay in the antimicrobial film packages were more pronounced, when applied by hermetical sealing to produce the modified atmospheres of low $O_2$ (<4.0%) and $CO_2$ concentrations with $6.3{\sim}9.0%$. The hermetically sealed packages of antimicrobial LDPE films also showed better retention of fruit firmness and did not give any negative effect on the physical and chemical qualities of strawberries.

• Applied Chemistry for Engineering
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• v.26 no.1
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• pp.23-28
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• 2015

Lacquer sap extracted from lacquer trees exhibits good thermal stabilities and antimicrobial properties. To apply these superior properties to functional packaging, polyurushiol (YPUOH) powders were prepared and blended into LDPE (low density polyethylene) to prepare three different LDPE/YPUOH composite films via a twin screw extruder system. Their morphology, thermal and antimicrobial properties as well as barrier properties of the LDPE/YPUOH composite films were thoroughly investigated to find out applicablities of the films as functional packaging materials. Although the interfacial interaction between LDPE and YPUOH was relatively weak, LDPE/YPUOH composite films exhibited good dispersion of YPUOH in LDPE, resulting in the enhanced thermal stability with YPUOH loading. Due to the good antibacterial property of as-prepared YPUOH, LDPE/YUOH composite films also showed an excellent antibacterial activity (R) of 99.9% against E. coli. Furthermore, the moisture barrier property of LDPE/YPUOH composite films increased with increasing YPUOH contents. Incorporating the relatively low amount of YPUOH in LDPE resulted in the apparent enhancement in thermal stabilities, antibacterial and moisture barrier properties, which made them promising candidates as a functional filler for packaging materials.

• Restorative Dentistry and Endodontics
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• v.16 no.1
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• pp.226-235
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• 1991

Therapeutic use of antibiotics in the pulpal disease should reduce the clinical symptoms and pathogenic microflora in the pulp. The purpose of this study was focused on local drug delivery into the root canal in endodontic therapy. Monolithic films from polycaprolactone and polyethylene glycol preparations with minocycline were prepared, and then the antimicrobial effect of these films on necrotic canal was tested. A total 17 necrotized pulp teeth were sampled before and 1 week after insertion of film into the pulp. Bacterial culture were performed with anaerobical condition and seeded in the 5 selective and non - selective media for 7 days in $37^{\circ}C$ of anaerobic chamber. Bacterial identification were performed with Gram staining, biochemical test, and API kit There was significantly decreased of anaerobic and aerobic microflora of 13 among 17 patients after therapy. Among the identified microflora, Streptococcus species, black - pigmented species and Fusobacterium species were significantly reduced 1 week after treatment with local delivery antibiotics. Furthermore, clinical symptoms included in pain and local swelling were continuousely reduced after therapy. These results suggest that local drug delivery with minocycline is effeicient to treat the endodontic involved teeth for releasing clinical symptoms and microbiological shifting.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.23 no.3
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• pp.133-141
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• 2017

This article described the development of transparent antimicrobial oxo-biodegradable (AOB) film with the function of enhanced freshness of food by employing oxo-biodegradable masterbatch (MB) and antimicrobial MB together with organic metal salt, organic acid, or unsaturated fatty acid. Antibacterial test of the AOB film with the different contents of the antimicrobial MB resulted in the significant freshness extension of plum. Tensile strength and elongation rate of the AOB films before UV treatment were similar to those of polyethylene films used as control. The reduced mechanical properties of AOB film after UV treatment (340 nm) suggested that the AOB film could be degraded by oxo biodegradation. The developed AOB films can effectively prevent decomposition of food by providing antibacterial function and preserving freshness.

• Journal of Food Hygiene and Safety
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• v.23 no.3
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• pp.227-232
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• 2008

The purpose of this study was to investigate the antibacterial effect of films on shelf-life and microbiological Safety of pork meat. Effects of antimicrobial films against total aerobic bacteria, Escherichia coli O157:H7, Listeria monocytogenes, Salmonella Typhimurium, Staphylococcus aureus in pork meat were evaluated during storage of 14 days at $5^{\circ}C,\;10^{\circ}C\;and\;15^{\circ}C$. Antimicrobial films were developed with addition of a natural substance, wasabi extracts(Wasabia japonica). At $5^{\circ}C$ storage, growth of total aerobic bacteria, E. coli O157:H7, L. monocytogenes were inhibited higher than at 10 and $15^{\circ}C$. Especially, the numbers of S. Typhimurium and S. aureus were increased gradually at $5^{\circ}C$ even in the control sample, and it takes more than 14 days to increase in every sample upto 6 $log_{10}cfu/g$. The higher antimicrobial effects of the films were observed at storage of $5^{\circ}C$ than at $10^{\circ}C$ and $15^{\circ}C$. There was a limit of a single treatment of antimicrobial film to prolong shelf-life of pork meat. The synergistic effect of antimicrobial film were observed with addition of refrigeration at $5^{\circ}C$.

• 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.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.26 no.3
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• pp.125-131
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• 2020

Carrageenan-based functional films were prepared by adding two different types of sulfur nanoparticles (SNP) synthesized from sodium thiosulfate (SNPSTS) and elemental sulfur (SNPES). The films were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction spectroscopy (XRD), and thermal gravimetric analysis (TGA). Also, film properties such as UV-visible light transmittance, water contact angle (WCA), water vapor permeability (WVP), mechanical properties, and antibacterial activity were evaluated. SNPs were uniformly dispersed in the carrageenan matrix to form flexible films. The addition of SNP significantly increased the film properties such as water vapor barrier and surface hydrophobicity but did not affect the mechanical properties. The carrageenan/SNP composite film showed some antibacterial activity against foodborne pathogenic bacteria, L. monocytogenes and E. coli.

• Journal of Environmental Health Sciences
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• v.47 no.1
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• pp.55-63
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• 2021

Objectives: Cefotaxime is an antibiotic used to treat several bacterial infections. Specifically, it is used to treat pelvic inflammatory disease, meningitis, pneumonia, urinary tract infections, and sepsis. It is given by injection into either a vein or muscle. Antibacterial polymers prepared by chemical bonding and simple blending of antibacterials into polymers has attracted much interest because of their long-lasting antibacterial activity. This study attempted to review the possibility of hydrogel films as functional antibacterial materials by antimicrobial activity. Methods: In this study, CTX-PAA was synthesized by the chemical reaction of polyacrylic acid with cefotaxime by N,N'-Dicyclohexylcarbodiimide (DCC) method. Synthetic antibacterial hydrogel films were then prepared with PVA and CTX-PAA for functional application. Results: The increase in the cefotaxime content of the hydrogel films showed a similar decrease in tensile strength and elongation. The values of films impregnated with chemically bonded cefotaxime showed no significant difference. Antibacterial susceptibility was determined against Streptococcus pneumoniae and Escherichia coli using a standardized disc test. Conclusion: The synthetic antibacterial hydrogel films exhibited broad susceptibility against Streptococcus pneumoniae and Escherichia coli. Notably, the antibacterial effect of antibacterial hydrogel films against Grampositive (Streptococcus pneumoniae) was superior to that against Gram-negative (Escherichia coli).

• Journal of Microbiology and Biotechnology
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• v.15 no.4
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• pp.815-822
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• 2005

In order to extend the shelf-life of packaged or coated foods, an antibacterial edible film was developed from soybean meal that had been fermented with Bacillus subtilis under the optimum condition of pH 7.0-7.5 and $33^{\circ}C$ for 33 h. The water vapor permeability of the fermented film ($86.0 mg/cm^2{\cdot}h$) was higher than those of normal soybean films ($66.9 mg/cm^2{\cdot}h$). Protein solubility of the fermented film was also higher than ordinary soy protein film at the pH range of 3 -10. The fermented soybean film had higher tensile strength and lower $\%$ elongation (elongation rate) than the ordinary soybean film, mainly because partial hydrolysis of proteins in the soybean film occurred during fermentation. Antimicrobial properties of the fermented film on foodstuffs were measured by placing the films on surime, jerked beef, and mashed sausage media; containing $10^2-10^3$ CFU/plate of foodborne pathogenic bacteria, and showed significantly higher inhibitory effects on the growths of all the indicating bacteria. The film could be used as a packaging material in the food industry. However, before direct application of the fermented film to the commercial food industry, its poor mechanical and antibacterial properties need to be improved.