• Journal of the Korean Ceramic Society
• /
• v.54 no.3
• /
• pp.228-234
• /
• 2017

This work was achieved on the preparation of antimicrobial ceramic hybrid polyethylene films with natural chamomile extracts. The antimicrobial activity and various physicochemical properties of the prepared films were evaluated. Various natural products demonstrated antimicrobial activity. Among them, chamomile extracts showed strong activity and no cytotoxicity rather than that of the natural extracts. Porous ceramic materials were synthesized and demonstrated loading and controlled release of natural antimicrobial extracts. Furthermore, chamomile loaded ceramic hybrid films showed antimicrobial activity that was maintained for over 15 days.

• Journal of Microbiology and Biotechnology
• /
• v.17 no.3
• /
• pp.520-523
• /
• 2007

Edible films of gelatin and com zein were prepared by incorporating nisin to the film-forming solutions. Com zein film with nisin of 12,000 IU/ml had an increase of 11.6 MPa in tensile strength compared with the control, whereas gelatin film had a slight increase with the increase of nisin concentration added. Water vapor permeability for both com zein and gelatin films decreased with the increase of nisin concentration, thus providing a better barrier against water. Antimicrobial activity against Listeria monocytogenes increased with the increase of nisin concentration, resulting in 1.4 log cycle reduction for com zein film and 0.6 log cycle reduction for gelatin film at 12,000 IU/ml. These results suggest that incorporation of nisin into com zein and gelatin films improve the physical properties of the films as well as antimicrobial activity against pathogenic bacteria during storage, resulting in extension of the shelf life of food products by providing with antimicrobial edible packaging films.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.27 no.4
• /
• pp.675-681
• /
• 1998

Low density polyethlene(LDPE0 films of 50${\mu}{\textrm}{m}$ thickness were fabricated with addition of antimicrobial agents of Rheum palmatum extract, Coptis chinensis extract, sorbic acid and Ag-substitude inorganic zirconium matrix in 1% concentration. The films were compared in physical properties, tested in antimicrobial activity against some selected microorganisms on the agar plate medium and then applied for packaging fresh curled lettuce and cucumber to preserve their qualities. The films with Rheum palmatum extract, Coptis chinensis extract, and Ag-substituted inorganic zirconium matrix did not show any antimicrobial activity on the disk test against Escherichia coli, Staphylococcus aureus, Leuconostoc mesenteroides, Saccharomyces cerevisiae, Aspergillus niger, Aspergillus oryzae, Penicilluium chrysogenum, while film with sorbic acid did against E. coli, S. aureus and L. mesenteroides. The added antimicrobial agents changed the color and light transmittance of the films, but did not affect their mechanical tensile strength, heat shrinkage and wettability. For the packaged curled lettuce and cucumber stored at 5$^{\circ}C$ and 1$0^{\circ}C$, all the LDPE films impregnated with antimicrobial agents showed the reduced growth of total aerobic bacteria in the vegetables compared with control film without any additive until it reached the level around 108/g. They did not give any negative effect on other quality attributes during storage.

• Food Science and Preservation
• /
• v.10 no.4
• /
• pp.574-583
• /
• 2003

There have been a lot of research efforts on development of active food packaging structures and materials in the form of plastic films and containers, along with investigating novel polymers and bioactive compounds for packaging purpose, in order to improve storage stability and safety of foods during distribution and sale. Recently, great interests focus on antimicrobial package films, as an active packaging system, made from synthetic plastic polymer% and natural biopolymers containing various antimicrobial substances for food packaging applications. In this active system, substances are slowly released onto the food surface. However, antimicrobial activity as well as physical properties of the films can be significantly influenced by several factors such as polymer matrix, antimicrobial compounds, and interactions between polymers and compounds. Thus, this study reviews present status of antimicrobial food packaging films in overall performance aspects including types of polymers and active substances, test for antimicrobial activity, and changes in mechanical and antimicrobial properties by preparation method.

• Korean Chemical Engineering Research
• /
• v.49 no.4
• /
• pp.449-455
• /
• 2011

This study was performed to develop antimicrobial films using polyvinyl alcohol and methyl cellulose. Methyl cellulose and polyvinyl alcohol films plasticized with PEG(polyethylene glycol) were prepared by solvent casting process under addition of 0.025~1.0 wt% ampicillin and 0.1~1.0 wt% streptomycin as an antimicrobial agent. The mechanical properties of prepared films were examined by universal testing machine(UTM). Tensile strength of methyl cellulose films was 15.44~21.70 $N/mm^2$. Tensile strength of PVA(15 wt%) film was 20.2~51.5 $N/mm^2$, and the tensile strength of the antimicrobial films were decreased linearly with increasing the antibiotic loading amount up to 1 wt%. Antimicrobial activities of PVA and methyl cellulose films containing ampicillin and streptomycin through the disc diffusion test for the Staphylococcus aureus and Escherichia coli. The antimicrobial activity of methyl cellulose films and PVA containing ampicillin were higher than that of containing streptomycin methyl cellulose films. The results indicate the films may be a proper materials for antimicrobial packing applications.

• Microbiology and Biotechnology Letters
• /
• v.48 no.1
• /
• pp.12-23
• /
• 2020

Edible films containing antimicrobial agents can be used as safe alternatives to preserve food products. Essential oils are well-recognized antimicrobials. However, their low water solubility, volatility and high sensitivity to oxygen and light limit their application in food preservation. These limitations could be overcome by embedding these essential oils in complexed product matrices exploiting the encapsulation efficiency of β-cyclodextrin. This study focused on the maximization of β-cyclodextrin production using cyclodextrin glucanotransferase (CGTase) and the evaluation of its encapsulation efficacy to fabricate edible antimicrobial films. Response surface methodology (RSM) was used to optimize CGTase production by Brevibacillus brevis AMI-2 isolated from mangrove sediments. This enzyme was partially purified using a starch adsorption method and entrapped in calcium alginate. Cyclodextrin produced by the immobilized enzyme was then confirmed using high performance thin layer chromatography, and its encapsulation efficiency was investigated. The clove oil/β-cyclodextrin inclusion complexes were prepared using the coprecipitation method, and incorporated into chitosan films, and subjected to antimicrobial testing. Results revealed that β-cyclodextrin was produced as a major product of the enzymatic reaction. In addition, the incorporation of clove oil/β-cyclodextrin inclusion complexes significantly increased the antimicrobial activity of chitosan films against Staphylococcus aureus, Staphylococcus epidermidis, Salmonella Typhimurium, Escherichia coli, and Candida albicans. In conclusion, B. brevis AMI-2 is a promising source for CGTase to synthesize β-cyclodextrin with considerable encapsulation efficiency. Further, the obtained results suggest that chitosan films containing clove oils encapsulated in β-cyclodextrin could serve as edible antimicrobial food-packaging materials to combat microbial contamination.

• Polymer(Korea)
• /
• v.37 no.6
• /
• pp.677-684
• /
• 2013

Zinc alginate films were prepared by a film maker from sodium alginate solutions of different weight ratios and then they solidified into 3 wt% content $ZnCl_2$ coagulation solution and washed and dried at a $60^{\circ}C$ oven for 20 min. The characteristics were measured by several methods (antimicrobial activity, viscosity, FTIR, TGA, SEM, EDS, contact angle, tensile strength and solubility) and the film properties were investigated. The antimicrobial test showed that the zinc alginate films result in excellent antimicrobial activity in the two strains (Klebsiella pneumonia, Staphylococcus). The surface of zinc alginate film from the solution of 9 wt% sodium alginate showed more uniform shape than any other films and the cross-section were hard and rough when the films were well-solidified by the $ZnCl_2$ solution. The tensile strength of zinc alginate films increased along with the concentration of sodium alginate solution due to the cross-linking, and the initial thermal decomposition temperature increased gradually.

• Korean Journal of Human Ecology
• /
• v.14 no.2
• /
• pp.321-330
• /
• 2005

The antimicrobial activity of PHB/chitosan films and the quality of white bread packaged with the films were investigated. Chitosan film showed the highest antimicrobial activity and PHB(L) film also showed high antimicrobial activity against Fusarium solani KCTC 6636 and Penicillium citreonigrum KCTC 6927. White bread packaged with chitosan film had good moisture retention. $L^*\;and\;b^*$ of white bread increased but $a^*$ did little change during storage regardless of the film kind. The TBA values of white bread packaged with chitosan or PHB(L) film slowly increased during storage. The springiness of white bread packaged with PHB(M), PHB(L) and chitosan film was high. The colony forming units of microorganisms for white bread packaged with chitosan film were low during storage. Therefore, PHB(M), PHB(L) and chitosan films were superior to PHB(H) and PHB films as package material for white bread.

• Polymer(Korea)
• /
• v.38 no.5
• /
• pp.580-587
• /
• 2014

Composite films of zinc calcium alginate were prepared by a film maker from 7 wt% sodium alginate solution and then they solidified into 3, 5 wt% content $ZnCl_2$, $CaCl_2$ solution followed by washing and drying at room temperature. The characteristics were measured with several methods (antimicrobial activity, water solubility, swelling ratio and viscosity, SEM, EDS) and the film properties were investigated. Composite films of zinc calcium alginate showed an increase in the water resistance by increasing $ZnCl_2$ and $CaCl_2$ content and the antimicrobial test showed that the calcium alginate as well as zinc alginate films result in excellent antimicrobial activity in the two strains, Staphylococcus and Escherichia coli. The results show the possible improvement of the physical properties of composite films.

• 한국포장학회:학술대회논문집
• /
• 2006.11a
• /
• pp.54-73
• /
• 2006

Four different types of chitosan-based nanocomposite films were prepared using a solvent casting method by incorporating with four types of nanoparticles, i.e., an unmodified montmorillonite (Na-MMT), an organically modified montmorillonite (Cloisite 30B), a Nano-silver, and a Ag-zeolite (Ag-Ion). X-ray diffraction patterns of the nanocomposite films indicated that a certain degree of intercalation was formed in the nanocomposite films, with the highest intercalation in the Na-MMT-incorporated films followed by films with Cloisite 30B and Ag-Ion. SEM micrographs showed that in all the nanocomposite films, except the Nanosilver-incorporated one, nanoparticles were dispersed homogeneously throughout the chitosan polymer matrix. Consequently, mechanical and barrier properties of chitosan films were affected through intercalation of nanoparticles, i.e., tensile strength (TS) increased by 7-16%, while water vapor permeability (WVP) decreased by 25-30% depending on the nanoparticle material tested. In addition, chitosan-based nanocomposite films, especially silver-containing ones, showed a promising range of antimicrobial activity.