Antimicrobial Food Packaging Materials Research Articles

Optimization of Physical and Mechanical Properties of an Active Film of PLA/EEP by a Full Factorial Design

AbstractThe objective of this work is to develop an active food packaging material based on poly (lactic acid) and ethanolic extracts propolis. Poly(lactic acid)/ethanolic extract propolis films are prepared by casting, using a three level full factorial design that allowed to study the parameters influencing Young's modulus and water absorption. Many experiments are carried out, with a suitable choice of two variables, leading to a mathematical model in the form of a first degree polynomial. The films are subjected to several analyzes: physical and mechanical properties and antibacterial activity. The results show that the optimal film is obtained with an amount of 14% w/w of ethanolic extracts propolis, giving an antimicrobial food packaging material with the following characteristics: amount of propolis extract: 0.14 g, Young's modulus: 1594.16 N mm−2, water absorption rate: 3%, breaking stress: 29.45% and elongation at break: 39.27%.

Chitosan-based film incorporated with essential oil nanoemulsion foreseeing enhanced antimicrobial effect.

Foodborne diseases are a huge problem that causes dramatic economic losses and threatens consumers' lives. Chitosan-based film incorporated with essential oil nanoemulsion would be an ideal solution to build smart food packaging. Thyme oil was formulated into nanoemulsion and checked for the droplet size, distribution, and physical stability. The prepared thyme oil nanoemulsion was incorporated with the chitosan-filmogenic mixture through continuous mixing. The filmogenic mixture was cast, dried, and assessed for their morphological, physical, mechanical, and molecular properties. In addition to investigating the antimicrobial activity against gram-negative (Escherichia coli spp.) and gram-positive (Bacillus subtilis spp.) bacteria. Thyme oil nanoemulsion showed a small droplet size (89-90nm) with considerable stability. Incorporating thyme oil nanoemulsion with the chitosan-based film did not cause great change in the film appearance and transparency, while enhanced the light barrier property. It caused noticeable changes to the film physical (ex., moisture content, water vapor permeability, among others) and mechanical (Tensile strength and elongation at break) properties. On the other hand, it improved the film thermal stability without causing a structural alteration in the film matrix. Incorporation of chitosan-based film with thyme nanoemulsion remarkably improved the antimicrobial activity against foodborne pathogens. Chitosan-based film incorporated with thyme oil nanoemulsion would be considered a promising antimicrobial food packaging material with considerable packaging properties, and substantial growth inhibitor of foodborne pathogens.

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.

Silver Decorated Bacterial Cellulose Nanocomposites as Antimicrobial Food Packaging Materials

Silver Decorated Bacterial Cellulose Nanocomposites as Antimicrobial Food Packaging Materials

Chitosan‐capped sulfur microparticles grafted on UV‐treated PET surface

Antimicrobial materials with immobilized particles are of considerable interest. Sulfur, as one of the abundant elements on earth, is cheap and environmentally friendly; therefore, sulfur particles (SPs) can be used as an effective, nontoxic and low‐cost alternative to metal particles. SPs were prepared by precipitation method using sodium thiosulfate and hydrochloric acid in the presence of chitosan as a stabilizer. Further, SPs were grafted on polyethylene terephthalate (PET) foil activated by ultraviolet radiation. The changes in surface properties of modified foils were characterized by contact angle measurement, electrokinetic analysis and X‐ray photoelectron spectroscopy (XPS). The contact angle decreased on the UV‐treated sample, owing to the formation of oxidized groups. The presence of nitrogen and sulfur on the polymer surface, revealed by XPS, showed that chitosan‐capped SPs were bound to this surface. The surface morphology of samples and particle sizes were examined by scanning electron microscopy. The size of SPs increased after grafting on surface to a few micrometres. The antibacterial activity of the PET samples was tested against Staphylococcus epidermidis and Escherichia coli bacteria strains. UV‐treated samples grafted with one of the tested chitosan‐capped SPs demonstrated antibacterial effect against both of the bacteria strains. This new nanocomposite has potential to be used in medical applications as an antibacterial agent or in food processing as an antimicrobial food packaging material. Food spoilage caused by microorganisms such as E. coli during distribution and storage has a major impact on food quality and shelf life.

Preparation of poly(butylene adipate-co-terephthalate)/ZnSnO3 composites with enhanced antimicrobial activity

Poly(butylene adipate-co-terephthalate) (PBAT) composites with ZnSnO3 nanosheets as inorganic dispersed constituent have been prepared by a convenient solution mixing method, where ZnSnO3 is obtained by hydrothermal synthesis. The structure and morphology of ZnSnO3 and PBAT/ZnSnO3 composite are characterized. The obtained composite films, made by drop casting, display significantly-improved antimicrobial activity against Gram-negative (E. coli) and Gram-positive (S. aureus) food-borne pathogenic bacteria. The results suggest that the PBAT/ZnSnO3 composites may serve as promising candidate for antimicrobial food packaging materials.

Enhancement of ��-Cyclodextrin Production and Fabrication of Edible Antimicrobial Films Incorporated with Clove Essential Oil/��-cyclodextrin Inclusion Complex

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.

Sodium Alginate-Based Green Packaging Films Functionalized by Guava Leaf Extracts and Their Bioactivities.

The aim of this work was to develop green and bioactive films with sodium alginate incorporating guava leaf extracts. Seven formulations were performed with a different sodium alginate: Guava leaf water extract (WE)/ethanolic extract (EE) proportions (100:0, 90:10, 85:15, 80:20), and glycerol were used as a plasticizer. The HPLC-PDA analysis showed the main phenolic compounds in WE were gallic acid, ellagic acid, quercetin-3-O-β-D-xylopyranoside, avicularin and quercetin. The main polyphenols in EE were rutin, isoquercitrin, quercetin-3-O-β-D-xylopyranoside, avicularin, quercitrin, quercetin and kaempferol. Guava leaf extracts could greatly enhance the antioxidant activity, antibacterial activity, tensile strength and water solubility of the sodium alginate film as well as the water barrier property, while inducing a decrease in the moisture content and elongation at the break. The FTIR and SEM analyses indicated that intermolecular hydrogen bonding between the guava leaf extract and sodium alginate resulted in a more compact structure in the composite films. These results indicated that sodium alginate-guava leaf extract films might be developed into antiradical and antimicrobial food packaging materials.

Poly(Lactic Acid)/Zno Bionanocomposite Films with Positively Charged Zno as Potential Antimicrobial Food Packaging Materials.

A series of PLA/ZnO bionanocomposite films were prepared by introducing positively surface charged zinc oxide nanoparticles (ZnO NPs) into biodegradable poly(lactic acid) (PLA) by the solvent casting method, and their physical properties and antibacterial activities were evaluated. The physical properties and antibacterial efficiencies of the bionanocomposite films were strongly dependent on the ZnO NPs content. The bionanocomposite films with over 3% ZnO NPs exhibited a rough surface, poor dispersion, hard agglomerates, and voids, leading to a reduction in the crystallinity and morphological defects. With the increasing ZnO NPs content, the thermal stability and barrier properties of the PLA/ZnO bionanocomposite films were decreased while their hydrophobicity increased. The bionanocomposite films showed appreciable antimicrobial activity against Staphylococcus aureus and Escherichia coli. Especially, the films with over 3% of ZnO NPs exhibited a complete growth inhibition of E. coli. The strong interactions between the positively charged surface ZnO NPs and negatively charged surface of the bacterial membrane led to the production of reactive oxygen species (ROS) and eventually bacterial cell death. Consequently, these PLA/ZnO bionanocomposite films can potentially be used as a food packaging material with excellent UV protective and antibacterial properties.

Polyvinyl alcohol/silver nanocomposite films fabricated under the influence of solar radiation as effective antimicrobial food packaging material

As the demand for ready-made food is increasing, it is necessary to develop effective food packaging materials with antimicrobial activity to ensure microbiological safety of food. For this, polyvinyl alcohol (PVA) based active food packaging material reinforced with silver nanoparticles (AgNPs) was prepared by solvent casting. Here, ginger rhizome extract was used as the reducing agent for the rapid in situ reduction of AgNO3 to AgNPs (gAgNPs) within the PVA matrix, under the influence of direct sunlight. Then the films were characterized by SEM, XRD, FTIR and UV-Vis spectrophotometry. Mechanical property analysis of PVA/gAgNP nanocomposite film showed its improved features when compared to neat PVA film. The presence of gAgNPs in the PVA/gAgNP film provided significant UV and light barrier properties together with profound antibacterial activity against the foodborne pathogen Salmonella Typhimurium and Staphylococcus aureus. Considering these excellent results, PVA/gAgNP film can expect to have promising food packaging application.

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.

Electrospun cellulose acetate and poly(vinyl chloride) nanofiber mats containing silver nanoparticles for antifungi packaging

Nanofiber mats of poly(vinyl chloride) (PVC) and cellulose acetate (CA) encapsulated with silver (Ag) nanoparticles were fabricated via electrospinning for potential use as antimicrobial food packaging materials. 16 wt% PVC was prepared in 1:1 w/w tetrahydrofuran—N,N-dimethylformamide while 16 wt% CA was prepared in 3:2 (w/w) Acetone—N,N-dimethylformamide. Scanning electron microscopy analysis showed that thinner fibers could be electrospun from cellulose acetate as compared to poly(vinyl chloride) at the same solution concentrations with fiber diameters ranging from 70 to 130 nm for cellulose acetate and 180–340 nm for poly(vinyl chloride). Nanofiber diameter reduced with addition and increase of silver nanoparticles from 0 to 1 wt%. Due to the smaller cellulose acetate nanofiber diameter, its mats had lower air permeability rates. Tensile strength tests indicated that the nanofiber mats had marginal to good tensile strength values relative to film based packaging materials. Antimicrobial examination of the nanofiber mats against yeast and mould indicated that there was inhibited growth of the microorganisms on mats containing silver nanoparticles.

Preparation and characterization of hybrid cationic hydroxyethyl cellulose/sodium alginate polyelectrolyte antimicrobial films

This study aimed to develop polyelectrolyte‐structured antimicrobial food packaging materials that do not contain any antimicrobial agents. Cationic hydroxyethyl cellulose was synthesized and characterized by Fourier‐transform infrared, 1H NMR, and 13C NMR spectroscopy. Its nitrogen content was determined by Kjeldahl method. Polyelectrolyte‐structured antimicrobial food packaging materials were prepared using hydroxyethyl cellulose, cationic hydroxyethyl cellulose, and sodium alginate. Antimicrobial activity of materials was defined by inhibition zone method (disc diffusion method). Thermal stability of samples was evaluated by thermal gravimetric analysis and differential scanning calorimetry. Surface morphology of samples was investigated by SEM. The obtained results prove that produced food packaging materials have good thermal and antimicrobial properties, and they can be used as food packaging material in many industries.

Combined Effect of Ultrasound Stimulations and Autoclaving on the Enhancement of Antibacterial Activity of ZnO and SiO₂/ZnO Nanoparticles.

This study investigates the antibacterial activity (ABA) of suspensions of pure ZnO nanoparticles (ZnO-NPs) and mesoporous silica doped with ZnO (ZnO-UVM7), as well as electrospun nanofibers containing those nanoparticles. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of these two materials were also determined under the same conditions. The results showed a concentration-dependent effect of antibacterial nanoparticles on the viability of Escherichia coli (E. coli). Moreover, the combination of the stimulations and sterilization considerably enhanced the antimicrobial activity (AMA) of the ZnO suspensions. Poly (lactic acid) (PLA) solutions in 2,2,2-trifluoroethanol (TFE) were mixed with different contents of nanoparticles and spun into nonwoven mats by the electrospinning process. The morphology of the mats was analyzed by scanning electron microscopy (SEM). The amount of nanoparticles contained in the mats was determined by thermogravimetric analysis (TGA). The obtained PLA-based mats showed a fibrous morphology, with an average diameter ranging from 350 to 450 nm, a porosity above 85%, but with the nanoparticles agglomeration on their surface. TGA analysis showed that the loss of ZnO-NPs increased with the increase of ZnO-NPs content in the PLA solutions and reached 79% for 1 wt % of ZnO-NPs, which was mainly due to the aggregation of nanoparticles in solution. The ABA of the obtained PLA mats was evaluated by the dynamic method according to the ASTM standard E2149. The results showed that, above an optimal concentration, the nanoparticle agglomeration reduced the antimicrobial efficiency of PLA mats. These mats have potential features for use as antimicrobial food packaging material.

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

Antimicrobial agent-free hybrid cationic starch/sodium alginate polyelectrolyte films for food packaging materials

This study aimed to develop polyelectrolyte structured antimicrobial food packaging materials that do not contain any antimicrobial agents. Cationic starch was synthesized and characterized by FT-IR spectroscopy and 1H NMR spectroscopy. Its nitrogen content was determined by Kjeldahl method. Polyelectrolyte structured antimicrobial food packaging materials were prepared using starch, cationic starch and sodium alginate. Antimicrobial activity of materials was defined by inhibition zone method (disc diffusion method). Thermal stability of samples was evaluated by TGA and DSC. Hydrophobicity of samples was determined by contact angle measurements. Surface morphology of samples was investigated by SEM. Moreover, gel contents of samples were determined. The obtained results prove that produced food packaging materials have good thermal, antimicrobial and surface properties, and they can be used as food packaging material in many industries.

Raman spectroscopy, electronic microscopy and SPME-GC-MS to elucidate the mode of action of a new antimicrobial food packaging material.

One critical challenge when developing a new antimicrobial packaging material is to demonstrate the mode of action of the antimicrobials incorporated into the packaging. For this task, several analytical techniques as well as microbiology are required. In this work, the antimicrobial properties of benzyl isothiocyanate, allyl isothiocyanate and essential oils of cinnamon and oregano against several moulds and bacteria have been evaluated. Benzyl isothiocyanate showed the highest antimicrobial activity and it was selected for developing the new active packaging material. Scanning electron microscopy and Raman spectroscopy were successfully used to demonstrate the mode of action of benzyl isothiocyanate on Escherichia coli. Bacteria exhibited external modifications such as oval shape and the presence of septum surface, but they did not show any disruption or membrane damage. To provide data on the in vitro action of benzyl isothiocyanate and the presence of inhibition halos, the transfer mechanism to the cells was assessed using solid-phase microextraction-gas chromatography-mass spectrometry. Based on the transfer system, action mechanism and its stronger antimicrobial activity, benzyl isothiocyanate was incorporated to two kinds of antimicrobial labels. The labels were stable and active for 140days against two mould producers of ochratoxin A; Penicillium verrucosum is more sensitive than Aspergillus ochraceus. Details about the analytical techniques and the results obtained are shown and discussed. Graphical Abstract Antimicrobial evaluation of pure compounds, incorporation in the packaging and study for mode of action on S. coli by Raman, SEM and SPME-GC-MS.

Short‐ and long‐term loss of carvacrol from polymer/clay nanocomposite film – a chemometric approach

AbstractA combination of partial least squares (PLS) regression and design of experiments was used to analyse and define the short‐ and long‐term loss mechanisms of carvacrol from polymer/clay nanocomposite films used as an antimicrobial food packaging material. Three formulation x variables were evaluated: type of nanoclay, concentration of nanoclay and concentration of compatibilizer agent. Five experimental y responses were measured: loss of carvacrol from the films stored at room conditions on the third and fifth days (short‐term loss); on the forty‐fifth and sixtieth days (long‐term loss); and the polymer/clay level of intercalation. All variables and responses were simultaneously calibrated by an ANOVA‐validated (P < 0.05) comprehensive PLS interaction model with a satisfactory R2 = 0.956 and Q2 = 0.505. A differentiation and discrimination of the mechanisms that control the loss of carvacrol over different periods of time was observed. Short‐term loss seems to be controlled mainly by direct molecular interactions in the interlayer space between carvacrol and the nanoclay organomodifier. Long‐term loss seems to be mainly controlled by diffusion within the nanocomposite matrix once carvacrol has left the nanoclay interlayer space, and it is closely related to the levels of intercalation reached in the nanocomposite. © 2016 Society of Chemical Industry

Production of antimicrobial membranes loaded with potassium sorbate using a supercritical phase separation process

The production of antimicrobial packaging is one of the most interesting challenges in the food industry; its scope is to prolong the shelf life of a food maintaining its safety and freshness. The major limitation of traditional techniques used to produce antimicrobial packaging, is the difficulty in controlling the release of the active agent from the device to the food surface. In this work, a supercritical phase inversion process has been tested to produce potassium sorbate (PS) loaded cellulose acetate (CA) membranes, to be inserted in food packaging. The membranes have been obtained at different process conditions (pressures 150–250 bar, temperatures 35–55 °C) and at different polymer concentrations (10, 15 and 20% w/w). PS to CA weight ratio has been maintained constant at 5% w/w for all the formulations. The best process parameter combination to obtain the longest PS release time (about 325 min) was 250 bar and 35 °C. The production of antimicrobial active packagings is one of the most attractive challenges in the food industry also catalyzed by consumers' demand for natural and safe foods and for environmental protection [1]. Antimicrobial food packaging reduces, inhibits or retards the growth of microorganisms that may be present in the food or packaging material itself [2], to extend the shelf life of the packed food. The most desired property is the controlled release of the antimicrobial agent to the food surface [3–6]. This characteristic is influenced by the technique used to produce the film. To overcome conventional processes limitations, it could be possible to use supercritical assisted processes, taking advantage of the properties of supercritical fluids, such as negligible surface tension, high diffusivity and low viscosity. In particular, a supercritical phase separation process has been successfully proposed to produce loaded polymeric membranes to be inserted in food packaging. [1] C.A. Campos, L.N. Gerschenson, S.K. Flores, Development of edible films and coatings with antimicrobial activity, Food Bioprocess Technol. 4 (2011) 849–875. [2] P. Appendini, J.H. Hotchkiss, Review of antimicrobial food packaging, Innov. Food Sci. Emerg. Technol. 3 (2002) 113–126. [3] M. Uz, S.A. Altınkaya, Development of mono and multilayer antimicrobial food packaging materials for controlled release of potassium sorbate, LWT—Food Sci. Technol. 44 (2011) 2302–2309. [4] P. Suppakul, J. Miltz, K. Sonneveld, S.W. Bigger, Active packaging technologies with an emphasis on antimicrobial packaging and its application, J. Food Sci. 68 (2003) 408–420. [5] A. Figoli, E. Mascheroni, S. Limbo, E. Drioli, Membrane for food packaging, chapter 10, in: V. Peinemann, S. Pereira Nunes, L. Giorno (Eds.), Membrane Technology: Volume 3: Membranes for Food Applications, Wiley-VCH Verlag GmbH & Co., Germany, 2010. [6] L. Vermeiren, F. Devlieghere, M. van Beest, N. de Kruif, J. Debevere, Development of the active packaging of foods, Trends Food Sci. Technol. 19 (1999) 77–86.

Nanoencapsulation and immobilization of cinnamaldehyde for developing antimicrobial food packaging material

Use of antimicrobial coatings on food packaging is one of the important technologies of active packaging for improving food safety. There is growing demand for natural antimicrobials because of fear of adverse health effects of synthetic preservatives. The objectives of this study were to compare antibacterial properties of free and nanoencapsulated cinnamaldehyde in solution; polylactic acid (PLA) surfaces cast with cinnamaldehyde; and glass and PLA surfaces coated with cinnamaldehyde nano-liposomes. Cinnamaldehyde was nano-encapsulated by lipid bilayers of polydiacetylene – N-hydroxysuccinimide (PDA–NHS) nano liposomes and immobilized on glass slides and PLA films. Glass surfaces immobilized with nano-encapsulated cinnamaldehyde showed significant antibacterial activity against Escherichia coli W1485 and Bacillus cereus ATCC 14579, with reductions of 2.56 log10 CFU/ml and 1.59 log10 CFU/ml respectively in 48 h. PLA films cast with cinnamaldehyde also showed significant antibacterial activities against E. coli W1485 (2.01 log10 CFU/ml reduction) and B. cereus (4.81 log10 CFU/ml reduction). However, when the liposomal encapsulated cinnamaldehyde was immobilized on PLA films, it did not show any antibacterial activity. Glass surfaces coated with nano-encapsulated cinnamaldehyde may be used as an active packaging material in preserving liquid foods; however, further study is required to improve antimicrobial activities of PLA surfaces.