Antimicrobial Food Packaging Applications Research Articles

Characterization of zein nanofiber mats encapsulated with Foeniculum vulgare and Carum carvi essential oils as active packaging materials

This study aimed to encapsulate Foeniculum vulgare and Carum carvi essential oils (FVO and CCO) into the zein (ZN) nanofibers using an electrospinning technique and examine their application in retarding the growth of bacterial pathogens in ground beef meat during refrigerated storage conditions. The main fractions of FVO included trans-anethole (37.98%), α-fellandrene (15.09%), fenchone (10.58%), and tarragon (7.58%). CCO's major chemical compositions were also identified as α-terpinene (19.67%), α-terpinene-7-al (18.86%), p-menthatriene (16.90%), and cuminaldehyde (15.96%). The Fourier transform infrared spectroscopy analysis verified the molecular interaction between FVO/CCO and the ZN polymer. The thickness, tensile strength, elongation at break, and water vapor permeability of the nanofiber mats were in the range of 0.20–0.22 mm, 6.01–9.22 MPa, 5.57%–10.78%, and 1.05–2.72 × 10‾14 kg m/m2 s Pa, respectively. The initial count of 5 log CFU/g of Staphylococcus aureus, Listeria monocytogenes, and Yersinia enterocolitica in ground beef meat packaged with ZN + FVO 1 mL/100 mL + CCO 1 mL/100 mL nanofiber mats, as the best group, reached <1.00, 2.52, and 3.13 log CFU/g, respectively, at the end of the study (day 10), suggesting that the designated nanofiber mats can be utilized for antimicrobial food packaging applications.

Biogenesis of bacterial cellulose/xanthan/CeO2NPs composite films for active food packaging

The increasing significance of biopolymer-based food packaging can be attributed to its biodegradability and independence from petroleum-derived materials. Concurrently, metal oxide nanoparticles (NPs) have gained prominence as effective antimicrobial agents against both wild-type and antibiotic-resistant microbes. In this study, cerium oxide or ceria, CeO2, nanoparticles with an average diameter of 50 nm were synthesized via a green method utilizing Vibrio sp. VLC cell lysate supernatant. The synthesized CeO2 NPs displayed remarkable antimicrobial properties, inhibiting the growth of Escherichia coli and Staphylococcus aureus by 93.7 % and 98 %, respectively. To enhance the potential of bacterial cellulose (BC) for advanced applications, we developed a BC/xanthan/CeO2 nanocomposite using both ex situ and in situ techniques. The integration of CeO2 NPs within the nanocomposite structure not only improved the inherent properties of BC, but also rendered it suitable for use in active food packaging systems. The nanocomposite exhibited no significant cytotoxicity on the human dermal fibroblast (HDF) cells, confirming its safety. Nanocomposites containing biogenically synthesized CeO2 NPs demonstrated exceptional efficacy for reducing microbial contamination. Bread samples coated with nanocomposite films displayed no signs of microbial growth. These results support the application of BC/xanthan/CeO2 nanocomposites as suitable and effective coating materials for antimicrobial food packaging applications.

Mechanical, barrier, antibacterial and biodegradable properties of carrageenan/natamycin/graphene hybrid bio nanocomposite film for active antimicrobial food packaging applications

Mechanical, barrier, antibacterial and biodegradable properties of carrageenan/natamycin/graphene hybrid bio nanocomposite film for active antimicrobial food packaging applications

Preparation and study of the thermal, barrier and antibacterial properties of Polylactic acid-Fluorphlogopite-Silver nanoparticles nanocomposite films

Nowadays, there is an increasing need to develop new green biodegradable materials for active antimicrobial food packaging applications. In this work, polylactic acid-2 % Fluorphlogopite-1.5%silver nanoparticles (AgNPs) composites were prepared using melt extrusion. Films were characterized using Scanning Electron Microscopy, Transmission Electron Microscopy, X-Ray Diffraction, Differential Scanning Calorimetry, and Water Contact Angle measurements. Results showed a good dispersion of both fluorphlogopite and AgNPs in PLA which increased the surface roughness and hydrophobicity of PLA. Subsequently, the thermal, mechanical, and barrier properties of PLA nanocomposites were assessed. PLA-2%Fluorphlogopite-1.5%AgNPs showed a higher thermal stability than neat PLA while the mechanical properties remained unchanged. Furthermore, the excellent barrier properties of PLA were also unaffected by the introduction of fluorphlogopite and AgNPs. Finally, the antibacterial activity of the nanocomposites was assessed against three bacteria, S. aureus, E. faecalis, and E. coli and PLA-2%Fluorphlogopite-1.5%AgNPs inhibited almost completely the bacterial adhesion on the surface of the films.

Encapsulation of Lemongrass Oil for Antimicrobial and Biodegradable Food Packaging Applications

Antimicrobial gelatin nanofibers with lemongrass essential oil (Gt/LEO) were successfully fabricated by elec-trospinning as potential biodegradable and active food packaging. Following the determination of the key components and the composition of the LEO by a Gas chromatography-mass spectrometry (GC-MS) headspace analysis, the antimicrobial activity of LEO was tested against four different bacteria. Gt/LEO solutions were prepared and characterized before the electrospinning process. All the prepared solutions could be electro-spun, and the effect of LEO on electrospinnability was investigated by measuring conductivity, surface tension, and dielectric constant. The average diameter of pure gelatin nanofibers was 110 ± 39 nm and increased with the rise in essential oil content, similar to other studies. The structure of all nanofibers was smooth, stable, homogenous, and bead-free. The maximum growth inhibition rate (GIR) of Gt/10% LEO nanofilms was 99.09% against Staphylococcus aureus and 96.63% for Salmonella Typhimurium. Nanofilms incorporated with and without LEO displayed similar major Fourier transform infrared (FTIR) spectroscopy peaks showing the effective penetration of LEO in gelatin fibers without chemical interaction or destroying the structure of LEO or gelatin. Thermal analyses indicated that thermal stability of the essential oil enhanced by encapsulation. Overall, this study demonstrates that Gt/LEO nanofibers have a promising prospect in the area of antimicrobial food packaging.

Sustainable use of biowaste for synthesis of silver nanoparticles and its incorporation into gelatin‐based nanocomposite films for antimicrobial food packaging applications

AbstractBiodegradable nanocomposite films have been developed by incorporating silver nanoparticles (AgNPs) into the gelatin biopolymer matrix for food packaging applications. AgNPs were biologically synthesized using industrial food waste, namely, cassava tuber peels. The cassava peels mediated synthesized AgNPs exhibited a maximum absorbance peak at 434.4 nm in the UV–Vis spectrum. High‐resolution transmission electron microscopy results revealed spherical shaped particles with a size range of 10–45 nm. The presence of elemental silver and crystalline nature of AgNPs was confirmed by Energy‐dispersive X‐ray spectroscopy and X‐ray diffraction analyzes. AgNPs showed significant antimicrobial activity against foodborne pathogens. Field emission scanning electron microscopy images of the films showed the successful incorporation of AgNPs into the gelatin matrix. AgNPs integration has demonstrated improvement in the mechanical and barrier properties of nanocomposite films. The gelatin–AgNPs nanocomposite films have resulted in an excellent notable increase in the shelf life of sapodilla fruits. This confirms that the gelatin–AgNPs nanocomposite films are ideal for the food packaging industry to extend the shelf life of packaged food.Practical applicationsThe use of silver nanoparticles as an antimicrobial in the field of food technology has been of great interest in recent years. The present study highlights the importance of the use of industrial food waste for the synthesis of silver nanoparticles and its incorporation into the gelatin matrix for the preparation of thin nanocomposite film. Gelatin–AgNPs nanocomposite film showed enhanced UV‐shielding and antimicrobial properties, which increased the shelf life of sapodilla fruits. AgNPs incorporated gelatin nanocomposite film could prove to be an effective antimicrobial food packaging material and an efficient way to extend the post‐harvest life of food.

From cheese whey permeate to Sakacin-A/bacterial cellulose nanocrystal conjugates for antimicrobial food packaging applications: a circular economy case study

Applying a circular economy approach, this research explores the use of cheese whey permeate (CWP), by-product of whey ultrafiltration, as cheap substrate for the production of bacterial cellulose (BC) and Sakacin-A, to be used in an antimicrobial packaging material. BC from the acetic acid bacterium Komagataeibacter xylinus was boosted up to 6.77 g/L by supplementing CWP with β-galactosidase. BC was then reduced to nanocrystals (BCNCs, 70% conversion yield), which were then conjugated with Sakacin-A, an anti-Listeria bacteriocin produced by Lactobacillus sakei in a CWP based broth. Active conjugates (75 Activity Units (AU)/mg), an innovative solution for bacteriocin delivery, were then included in a coating mixture applied onto paper sheets at 25 AU/cm2. The obtained antimicrobial food package was found effective in reducing Listeria population in storage trials carried out on a fresh Italian soft cheese (named “stracchino”) intentionally inoculated with Listeria. Production costs of the active material have been mainly found to be associated (90%) to the purification steps. Setting a maximum prudential 50% cost reduction during process up-scaling, conjugates coating formulation would cost around 0.89 €/A4 sheet. Results represent a practical example of a circular economy production procedure by using a food industry by-product to produce antimicrobials for food preservation.

Superior water stability and antimicrobial activity of electrospun gluten nanofibrous films incorporated with glycerol monolaurate

In this study, the gluten nanofibrous films incorporated with glycerol monolaurate (GML) were fabricated through electrospinning. With the increasing concentration of GML, the surface tension of the gluten solution decreased continuously, while the viscosity decreased at a lower concentration of 4% GML but then increased significantly. Compared to the spindle-in-string fiber morphology of the electrospun gluten film, the addition of GML resulted in uniform smooth nanofibers with diameters ranging from 317 to 149 nm. As indicated by the XRD and FTIR analysis, GML was uniformly dispersed in the gluten films through hydrogen bonding at lower concentrations, but crystalized at higher concentrations, leading to a stiffer but brittle network. The incorporation of GML caused a more hydrophilic film surface as evidenced by the more accelerated decrease in water contact angle, but endowed the gluten nanofibrous films with a superior water stability and excellent antimicrobial activities against Staphylococcus aureus and Escherichia coli. These results suggested the potentials of the electrospun GML incorporated gluten films with superior water stability for antimicrobial food-packaging applications.

Nanomaterial loaded chitosan nanocomposite films for antimicrobial food packaging

Food loss due to spoilage, constitutes is a great economic concern for the food industry. Nanotechnology, being an advanced field comes into play in order to overcome this major global issue of food spoilage. With the help of nanotechnology, unique food packaging techniques can be designed, which can minimise the spoilage and increase the shelf life of food materials. In this study, we prepared and characterised zinc oxide and silver nanomaterials and then prepared chitosan nanocomposite films followed by their characterization. The antimicrobial activity of these films was also evaluated on S. aureus and E. coli by disc assay and cell growth curve analysis. The results showed dose dependent antimicrobial activity of nanocomposites films. It was concluded that the silver-chitosan nanocomposite were more efficient, for use in antimicrobial food packaging applications as compared to the ZnO-chitosan nanocomposite.

Bacterial cellulose films with ZnO nanoparticles and propolis extracts: Synergistic antimicrobial effect

This study aimed to obtain possible materials for future antimicrobial food packaging applications based on biodegradable bacterial cellulose (BC). BC is a fermentation product obtained by Gluconacetobacter xylinum using food or agricultural wastes as substrate. In this work we investigated the synergistic effect of zinc oxide nanoparticles (ZnO NPs) and propolis extracts deposited on BC. ZnO NPs were generated in the presence of ultrasounds directly on the surface of BC films. The BC-ZnO composites were further impregnated with ethanolic propolis extracts (EEP) with different concentrations.The composition of raw propolis and EEP were previously determined by gas-chromatography mass-spectrometry (GC-MS), while the antioxidant activity was evaluated by TEAC (Trolox equivalent antioxidant capacity). The analysis methods performed on BC-ZnO composites such as scanning electron microscopy (SEM), thermo-gravimetrically analysis (TGA), and energy-dispersive X-ray spectroscopy (EDX) proved that ZnO NPs were formed and embedded in the whole structure of BC films. The BC-ZnO-propolis films were characterized by SEM and X-ray photon spectroscopy (XPS) in order to investigate the surface modifications. The antimicrobial synergistic effect of the BC-ZnO-propolis films were evaluated against Escherichia coli, Bacillus subtilis, and Candida albicans. The experimental results revealed that BC-ZnO had no influence on Gram-negative and eukaryotic cells.

Biocompatible silver nanoparticles/poly(vinyl alcohol) electrospun nanofibers for potential antimicrobial food packaging applications

Abstract Nanotechnology is expected to transform many areas of food science as there is a growing demand for increased fresh food shelf life as well as the need of protection against foodborne diseases, thus, urging for the development of antimicrobial food packaging using the polymer embedded metal nanoparticles. In the present study, the stable silver nanoparticles (AgNPs) were synthesized by a green route using Vitis vinifera (black grapes) fruit peel, characterized and evaluated for their antimicrobial activity against Bacillus cereus, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The synthesized AgNPs exhibited maximum absorbance at 421.6 nm in the ultraviolet-visible (UV–vis) spectrum. The transmission electron microscopy (TEM) image revealed spherical shaped nanoparticles of average particle size about 30 nm. The energy-dispersive X-ray (EDX) and X-ray diffraction (XRD) analyses confirmed the presence of elemental silver and the crystalline nature of AgNPs. A unique green organic-inorganic hybrid nanofibers (poly(vinyl alcohol)–AgNPs) were developed through the electrospinning method, by incorporating the synthesized AgNPs in poly(vinyl alcohol) matrix, for fruits preservation. The AgNPs and AgPVA nanofiber showed good antibacterial activity against tested food pathogenic bacterial strains. The AgPVA nanofiber demonstrated an increased shelf life when surface-coated over the fruits, Citrus limon (lemon) and Fragaria ananassa (strawberry), by preventing the decaying caused due to food pathogens. These results indicated that AgPVA nanofiber can potentially be used as antimicrobial packaging for food preservative applications.

Carvacrol loaded halloysite coatings for antimicrobial food packaging applications

Abstract Antimicrobial thin film coatings that can be utilized in food packaging provide an effective approach to enhance food quality and safety. Here, the coating of polyethylene films with an antimicrobial thin film through a Layer-by-Layer (LbL) assembly is demonstrated. Halloysite nanotubes (HNTs) which are tubular clay nanoparticles were utilized for the encapsulation and sustained release of carvacrol, the active component of essential thyme oil. Antimicrobial thin film coatings of 225 nm thickness were prepared by the deposition of ten bilayers of chitosan (CHI) and carvacrol loaded HNTs onto the polyethylene surface by spray LbL. Coated films reduced the viability of a food pathogen, Aeromonas hydrophila by 85% and the aerobic count on chicken meat surfaces by 48%. Furthermore, coated film surfaces demonstrated lower bacterial attachment compared to control polyethylene films indicating their antibiofilm character. Composed of natural and safe components, antimicrobial coatings developed in this study provide a novel and effective approach to obtain antimicrobial food packaging materials that can greatly contribute to food safety.

Multifunctional ternary composite films based on PLA and Ag/alginate microbeads: Physical characterization and silver release kinetics

Novel multifunctional composite poly(lactic acid) (PLA) films with alginate microbeads containing silver nanoparticles (AgNPs) were developed for potential antimicrobial food packaging applications. AgNPs, 10–20 nm in size, were synthesized in a Na-alginate solution by a hydrothermal method yielding a sterile, pH neutral colloid solution of low viscosity that was electrostatically extruded to produce Ag/alginate microbeads (190 μm in size) with retained AgNPs. Dried microbeads were uniformly dispersed in PLA films with retained AgNPs as confirmed by UV–Vis spectroscopy and scanning electron microscopy. The films were characterized regarding thermal and mechanical properties as well as silver release in different food simulants. Results show that PLA matrix served as a diffusion barrier so that the released silver concentration in water after 10 days was within the prescribed limit of 0.05 mg kg−1 while the films induced inhibitory effects against Staphylococcus aureus in the agar diffusion test.

Influence of Mg doping on the structural, morphological, optical, thermal, and visible-light responsive antibacterial properties of ZnO nanoparticles synthesized via co-precipitation

Mg-doped zinc oxide (Zn1-xMgxO, where x = 0.000, 0.001, 0.003, 0.005, and 0.010 M) nanoparticles (MgZnO NPs) were synthesized via a co-precipitation method and subjected to various analyses for application as functional additives in food packaging. The MgZnO NPs were successfully formed at approximately 360 °C and showed an increase in the optical band gap with respect to the increase in the concentration of Mg doping. The X-ray diffraction and scanning electron microscopy analyses of MgZnO NPs confirmed the formation of hexagonal wurtzite structure and rod-like morphology. X-ray photoelectron spectra revealed that the Mg (1s) peaks centered at 1303.35 and 1303.38 eV were ascribed to the presence of Mg2+ replacing Zn2+. Transmission electron microscopy images showed rod shapes with the length of 208–650nm and width of 84–142 nm. Various concentrations of synthesized MgZnO NPs were investigated against a gram-negative (Escherichia coli - DH5α) bacterial strain under light and dark conditions. Among the studied samples, 0.010 M MgZnO NPs of concentration 3 mg/mL showed the best antibacterial activity under the light condition. MgZnO NPs revealed uneven ridges on the outer surface, which promote the diffusion ability of Zn2+ and increased production of reactive oxygen species, and consequently lead to bacterial lysis. Furthermore, this study demonstrates excellent feasibility for the application of MgZnO NPs as fillers with good antibacterial activity, especially in antimicrobial food packaging applications.

Antimicrobial and biodegradable food packaging applications of polycaprolactone/organo nanoclay/chitosan polymeric composite films

Biodegradable and antimicrobial polymeric food packaging materials are very important because of environmental problems, for quality, and the shelf life of the product. The aim of this paper is to produce antimicrobial and biodegradable food packaging films with polycaprolactone (PCL). Using the amount of PCL (w/w) as the basis and to control the degradation time and to give antimicrobial properties, 0.4 wt% of organo nano clay (C) and 25, 50, and 75 wt% chitosan (K), and the use of glycerol monooleate (GMO) or oleic acid (OA) as a plastifier (5, 10, 20, and 30 wt%) are added and 12 polymeric composite films were prepared. The samples were coded as PCL (P), organo nanoclay (C), oleic acid (O), and glycerol monooleate (G). For example, P_C0.4_G5 refers to the PCL composite film containing 0.4 wt% clay and 5 wt% glycerol monooleate (G). The disc diffusion procedure with Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus, and Candida albicans test microorganisms were used to evaluate the antimicrobial properties of the films. PCL_C0.4_O5, PCL_C0.4_G5, PCL_C0.4_G10_K25, PCL_C0.4_O10_K25, and PCL_C0.4_O20_K50 and neat chitosan films have antimicrobial properties. A small amount of organo nano clay, 0.4 wt%, has an antimicrobial effect on C. albicans. The PCL_C0.4_G10_K25 composite film has an antimicrobial effect on E. coli, P. aeruginosa, and C. albicans. Mechanical tests were performed, and it was observed that the mechanical properties of PCL composite films decrease with the addition of chitosan. J. VINYL ADDIT. TECHNOL., 24:376–387, 2018. © 2017 Society of Plastics Engineers

Nanocomposite films containing organoclay nanoparticles as an antimicrobial (active) packaging for potential food application

Polyethylene nanocomposite films containing combinations of organoclay (OC) nanoparticles were prepared using extrusion molding method. The physical (X-ray diffraction [XRD] and scanning electron microscopy [SEM]), mechanical (tensile strength [TS] and elongation at break [E]) and antibacterial properties of the films against gram positive and gram negative bacteria were evaluated. XRD results showed an increase in basal reflection and intercalated-exfoliated structure prepared. SEM images revealed that Cloisite 20A had better compatibility with the polyethylene matrix in such way that it distributed homogenously in the matrix. Incorporating nanoparticles into polyethylene matrix significantly improved mechanical properties of the films in terms of TS and E parameters. Among used organoclays, Cloisite 30B, and Cloisite 15A had the most and the least antibacterial effect, respectively. A combination of three studied OCs revealed a more pronounced antibacterial effect than that of single or binary mode. Furthermore, its effect on gram negative Escherichia coli, was more pronounced than gram positive Staphylococcus aureus. Practical applications Nanocomposite films studied in this research provide bacteriostatic activities with improving mechanical properties. The main feature of this study was to use a mixture of nanoparticles for an enhanced antibacterial effect and, therefore, to reduce metallic nanoparticles' concentration in the obtained active films. Thus, such packaging material is suggested for potential use as an optimal choice for antimicrobial food packaging applications.

Production and characterization of a new biodegradable fenugreek seed gum based active nanocomposite film reinforced with nanoclays

In the present work, fenugreek seed gum (FSG)/clay nanocomposite films were prepared with nanoclays (Na+ montmorillonite [MMT], halloysite [HNT] and Nanomer® I.44 P [NM]) at different amounts (0, 2.5, 5.0 and 7.5g clay/100g FSG) by solution casting method and characterized. Increasing amount of nanoclay significantly (P<0.05) improved oxygen barrier and thermal properties of the biodegradable films. Agar diffusion tests revealed that FSG based nanocomposite films exhibited strong antimicrobial properties against foodborne pathogens namely Listeria monocytogenes, Escherichia coli O157:H7, Staphylococcus aureus and Bacillus cereus independently of clay type and concentration. In the case of mechanical properties, nanoclay incorporation up to 5% provided higher (P<0.05) tensile strength (TS) properties while elongation at break (EB) values of the films significantly (P<0.05) decreased in the presence of clay in the film matrix. SEM micrographs showed that especially lower levels (up to 5%) of nanoclay reinforcements provided a homogeneous and smooth film structure. In conclusion, FSG based nanocomposite films reinforced with nanoclays up to 5% showed a precious potential to be used in antimicrobial food packaging applications.

Effect of Varying Filler Concentration on Zinc Oxide Nanoparticle Embedded Chitosan Films as Potential Food Packaging Material

Prevailing scenario of non-biodegradable food packaging materials worldwide was the motivation for this research. More than half of the packaging materials used today are non-biodegradable and lack one or the other feature that keeps it from being an ideal food packaging material. Based on the current need of food grade packaging materials, the present study illustrates the amelioration of the properties of biodegradable chitosan films with the incorporation of zinc oxide (ZnO) nanoparticles in varying concentration. The ZnO nanoparticles (ZnONPs) used as fillers in the chitosan films were synthesized by supersaturation method. They were characterized using UV–visible spectrophotometry, X-ray diffraction and field emission scanning electron microscopy (FE-SEM). The particles were observed to be around 100–200 nm in size. The chitosan films with varying concentration of ZnONPs were synthesized and characterized using Fourier transform infrared spectroscopy and FE-SEM. The films were studied for their thermal stability, water vapor transmission rate (WVTR) and mechanical properties. The thermal stability, as determined by Thermo Gravimetric Analysis and Differential Scanning Calorimetry increased slightly with increasing percentage of embedded ZnONPs while a substantial decrease in WVTR was observed. Mechanical properties also showed improvements with 77% increment in tensile modulus and 67% increment in tensile strength. The antimicrobial activity of the films was also studied on gram positive bacterium Bacillus subtilis (B. subtilis) and gram negative bacterium Escherichia coli (E. coli) by serial dilution method. A twofold and 1.5-fold increment in the antimicrobial activity was observed for B. subtilis and E. coli, respectively, with increased ZnONPs concentration in the films from 0(w/w) to 2%(w/w). Films thus prepared can prove to be of immense potential in the near future for antimicrobial food packaging applications.

Antibacterial and antifungal LDPE films for active packaging

Active antimicrobial packaging is a promising form of active packaging that can kill or inhibit microorganism growth in order to maintain product quality and safety. One of the most common approaches is based on the release of volatile antimicrobial agents from the packaging material such as essential oils. Due to their highly volatile nature, the challenge is to preserve the essential oils during the high‐temperature melt processing of the polymer, while maintaining high antimicrobial activity for a desired shelf life. This study suggests a new approach in order to achieve this goal. Antimicrobial active films are developed based on low‐density polyethylene (LDPE), organo‐modified montmorillonite clays (MMT) and carvacrol (used as an essential oil model). In order to minimize carvacrol loss throughout the polymer compounding, a pre‐compounding step is developed in which clay/carvacrol hybrids are produced. The hybrids exhibit a significant increase in the d‐spacing of clay and enhanced thermal stability. The resulting LDPE/(clay/carvacrol) films exhibit superior and prolonged antibacterial activity againstEscherichia coliandListeria innocua, while polymer compounded with pure carvacrol loses the antibacterial properties within days. The films also present an excellent antifungal activity againstAlternaria alternata, used as a model plant pathogenic fungus. Furthermore, infrared spectroscopy analysis of the LDPE/(clay/carvacrol) system displayed significantly higher carvacrol content in the film as well as a slower out‐diffusion of the carvacrol molecules in comparison to LDPE/carvacrol films. Thus, these new films have a high potential for antimicrobial food packaging applications due to their long‐lasting and broad‐spectrum antimicrobial efficacy. Copyright © 2014 John Wiley &amp; Sons, Ltd.

Development and characterization of carrageenan/grapefruit seed extract composite films for active packaging

Carrageenan-based antimicrobial films were developed by incorporation of grape fruit seed extract (GSE) at different concentration into the polymer using a solvent casing method and their physical, mechanical, and antimicrobial properties were examined. The carrageenan/GSE composite films appeared yellowish tint due to the polyphenolic compounds in the GSE. SEM analysis showed rough surface with sponge like structures on the cross section of the films. FT-IR results indicated at GSE had good compatibility with carrageenan. The amorphous structure of polymer films was not changed by the incorporation of GSE. But, the addition of GSE increased moisture content, water vapor permeability, and surface hydrophilicity of the films. The tensile strength and elastic modulus decreased with increasing content of GSE, however, the elongation at break increased significantly up to 6.6μg/mL of GSE then decreased thereafter. Thermal stability of the films was not influenced by GSE incorporation. The carrageenan/GSE composite films exhibited great antibacterial activity against food borne pathogens. These results suggest that the carrageenan-based composite films have a high potential for being used as an antimicrobial or active food packaging applications.