Active Packaging Applications Research Articles

Effect and mechanism of cellulose nanofibrils on the active functions of biopolymer-based nanocomposite films

Cellulose nanofibrils (CNFs) are superfine cellulose fibrils with a nanoscale diameter and have gained increasing attention due to their great potential in the food industry. However, the applications of CNFs in active food packaging are still limited. The objectives of this study were to develop biopolymer-based edible nanocomposite films using CNFs, corn starch, and chitosan, and to investigate the effect and mechanisms of CNFs on the active functions and properties of the nanocomposite films. Important functional properties of the films were measured and the films were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and Zetasizer. The results demonstrate that CNFs increased the rigidity of the films due to more hydrogen bonds being induced by CNFs (≥60%). Incorporating a high content of CNFs (≥60%) in the film resulted in enhanced filling effect on the structure of the biopolymer films, which significantly improved the light barrier, oxygen barrier and water vapor barrier capacities. As CNF content increased to 100%, the film opacity increased by 59%, while the peroxide value of corn oil protected with edible films was reduced by 23%. Furthermore, the antimicrobial properties of the edible films with 80% and 100% CNFs were increased by up to 2logCFU/g on day 8 in a beef model, due to more positive charges in the films and improved blocking effects on oxygen. These results demonstrate that CNFs can effectively enhance the antimicrobial effect and barrier properties of biopolymer-based nanocomposite films and have great potential in applications of active packaging for food products.

Wool keratin film plasticized by citric acid for food packaging

Wool keratin (natural resource) and citric acid (effective preservative) were mixed in water to produce a transparent film for application in active packaging. This film showed excellent biocidal effect, high elongation value (600%) and little loss of keratin after immersion in water. The capability of citric acid to bind keratin macromolecules by hydrogen bonds is probably responsible for the improvement of film's extensibility. On the other hand, the study of FT-IR spectrum allows understanding that the presence of citric acid in aqueous solution enhances the content of alpha helix structure in the film, with a reduction in the amount of side chain and disordered conformations in the macromolecular structure. Carrot shelf-life was qualitatively improved with this film in comparison with a commercial film for preserving food. Consequently, this film can have possible application for food packaging as a substitute of synthetic polymers replacing them with a natural, environmental friendly and renewable resource.

Alginate/Lignosulfonate Blends with Photoprotective and Antioxidant Properties for Active Packaging Applications

Sodium alginate/ammonium lignosulfonate blend solutions and thin films with different compositions have been prepared and studied. The rheology of the film forming solutions was comparatively evaluated and was established the effect of lignosulfonate incorporation onto sodium alginate solution properties and partial compatibility of components was found. The shear-thinning behaviour of the ALG/LS solutions was better evidenced at high ALG content, suggesting that the time required for the reorganization of the network structure is longer for the samples containing predominantly ALG, because its structure is damaged by increasing shear rate. The structural, morphological, optical and antioxidant properties of the crosslinked ALG/LS blend films were investigated with the aim to identify their potential as new active materials with photoprotective and antioxidant properties. The ATR-FTIR spectroscopy revealed the hydrogen bonding interactions between the components and scanning electron microscopy showed the modified microstructure of the blend films depending on composition. The surface topography changes have been evidenced by atomic force microscopy, showing an increased average surface roughness when the increasing lignosulfonate amount was incorporated into ALG matrix. The optical properties measurements revealed the light barrier properties of the blend films and the antioxidant activity evaluation showed the enhanced radical scavenging activity of the films with higher lignosulfonate content.

Development of antimicrobial active film containing CINnamaldehyde and its application to snakehead (Ophiocephalus argus) fish

AbstractActive packaging containing plant essential oils as a food preservation method is attracting more and more attention. Bioactive films based on ethylene vinyl alcohol copolymer (EVOH) incorporating with and without cinnamaldehyde (CIN）were prepared and characterized in this study. Physical and mechanical properties including tensile strength, elongation at break, water vapor permeability (WVP), oxygen permeability (OP), thermogravimetric analysis (TGA), and SEM image were investigated. Then active properties including release of bioactive element, antioxidant and antibacterial ability of the film sample were also conducted. Finally, the preservative effects of active films on snakehead dices stored at 4 ± 1 °C were performed by analyzing changes in pH value, water loss rate (WLR), total bacterial counts (TBC) and total volatile basic nitrogen (TVB‐N). The results showed that film A with CIN possessed higher tensile strength and lower OP compared to those of EVOH film. Moreover, the film with active element had significant antioxidant and antibacterial ability. The radical scavenging rate of the active film reached as high as 39.01%. On day 10, the TBC of fish dices in EVOH film reached 6.07 log CFU/g and the TVB‐N was 16.83 mgN/100 g, while it took 14 days for fish dices packed with film A to reach similar levels. Therefore, active packaging may prolong shelf life of aquatic food and have significance for food preservation.Practical applicationsPackaging is an essential part of food preservation. Active packaging containing antimicrobial/antioxidant compounds should extend shelf life of the products. Ethylene vinyl alcohol copolymer (EVOH) is well known packing material for its excellent oxygen barrier property. Cinnamaldehyde (CIN) is extracted from Cinnamomum cassia Presl bark and exhibits antimicrobial activity against a wide range of microorganisms. The addition of CIN into EVOH not only enhances physical and mechanical properties of the film, but also shows significant antioxidant and antibacterial ability, which can prolong the shelf life of the products. The preservative effects of the active film on fresh snakehead fish presented in this study are valuable information for practical application of active packaging to aquatic products preservation in particular, and food in general.

Oregano essential oil-based natural antimicrobial packaging film to inactivate Salmonella enterica and yeasts/molds in the atmosphere surrounding cherry tomatoes

This study investigated the effectiveness of a polyvinyl alcohol (PVA) film containing the natural antimicrobial oregano essential oil (OEO) as an active packaging application for decreasing the microbial growth. The film exerted an antimicrobial effect via the atmosphere surrounding the food rather than direct contact, thereby preserving the quality of cherry tomatoes. A packaging film containing microencapsulated OEO was developed. The loading content increased gradually (104.29–234.29 μg OEO/mg film) with the amount of OEO incorporated (1%, 2%, and 3%), where the PVA films containing 2% OEO had the highest loading efficiency (91.64%), followed by 1% OEO (90.96%) and 3% OEO (88.38%). The antimicrobial activities of the films were evaluated by applying it to fresh cherry tomatoes at 4 °C and 22 °C for 7 days. The large 2% OEO film as well as both the small and large 3% OEO films had strong antimicrobial effects against Salmonella enterica, molds and yeasts, and mesophilic aerobic bacteria. The changes in the hardness, weight, and color of the cherry tomatoes during storage did not differ significantly. The films could be utilized as a packaging material for fresh produce with antimicrobial effects because of the controlled atmosphere surrounding the food rather than by direct contact.

Application of encapsulated essential oils as antimicrobial agents in food packaging

Recently natural antimicrobials have attracted a great deal of attention from the food industry. Innovations in food packaging have also been focused on the incorporation of these active additives in polymer matrices with the purpose of extending foods shelf life. Essential oils (EOs) from aromatic plants are potent antimicrobial agents. However, their volatility, low solubility in water, and susceptibility for oxidation limits their use. EOs encapsulation is one of the options to reduce these effects and to improve their biological activities. In this review, the relevance of EOs encapsulation and their incorporation into food packaging are discussed. Application of active antimicrobial packaging, based on encapsulated EOs, to foods is also addressed to evaluate their influence in food shelf life.

Antioxidant protection of cooked meatballs during frozen storage by whey protein edible films with phytochemicals from Laurus nobilis L. and Salvia officinalis

The aim of this study was to assess the effectiveness of whey protein isolate based edible films (WPFs) incorporated with natural antioxidant extracts (NAE) from laurel (LA, Laurus nobilis L.) or sage (SA, Salvia officinalis.) on the oxidative stability of cooked meatballs during frozen storage at −18 °C for 60 days. TBA values of the meatballs with NAE-WPF were lower than the TBA values of the meatballs with WPF and the control (C) group of samples. Higher antioxidant activity by LA-WPF than SA-WPF was determined with a 2,2′-diphenyl-2-picrylhydrazyl radical-scavenging assay. Incorporation of NAE from LA or SA into the edible films (EFs) resulted in reduced para-Anisidine value (p-Av) (P < 0.05) in cooked meatballs. Total phenolic compound content was higher in meatballs treated with NAE-WPF than in the C group suggesting that these natural compounds contributed to the oxidative stability of frozen meatballs. This study shows that the application of an antioxidant active packaging with LA or SA to meatballs is a feasible and effective antioxidant strategy for retarding oxidative changes in cooked and subsequently frozen comminuted meat products.

Sugar-based poly (anhydride-ester) containing natural antioxidants and antimicrobials: Synthesis and formulation into polymer blends

Thymol, a naturally occurring antioxidant and antimicrobial, is commonly researched for active packaging applications to deter food spoilage and bacterial growth. However, the high temperature necessary for processing often volatilizes the thymol, reducing its utility. To overcome this processing limitation, sugar-based poly(anhydride-esters) comprising thymol and compounds generally regarded as safe (succinic and tartaric acid) were successful prepared via mild solution polymerization methods. In vitro release studies demonstrated a sustained thymol release over 3 weeks at therapeutically relevant concentrations. Furthermore, the released thymol displayed antioxidant and antimicrobial activities as indicated by a 2,2-diphenyl-1-picrylhydrazyl radical scavenging and Kirby–Bauer disk diffusion assays, respectively. High-temperature melt blending with low-density polyethylene revealed that the chemical incorporation of thymol into a polymer backbone overcame volatility issues and maintained relevant bioactivity.

Surface attachment of active antimicrobial coatings onto conventional plastic-based laminates and performance assessment of these materials on the storage life of vacuum packaged beef sub-primals

Two antimicrobial coatings, namely Sodium octanoate and Auranta FV (a commercial antimicrobial composed of bioflavonoids, citric, malic, lactic, and caprylic acids) were used. These two antimicrobials were surface coated onto the inner polyethylene layer of cold plasma treated polyamide films using beef gelatin as a carrier and coating polymer. This packaging material was then used to vacuum pack beef sub-primal cuts and stored at 4 °C. A control was prepared using the non-coated commercial laminate and the same vacuum packaged sub-primal beef cuts. During storage, microbial and quality assessments were carried out. Sodium octanoate treated packages significantly (p < 0.05) reduced microbial counts for all bacteria tested with an increase of 7 and 14 days, respectively compared to control samples. No significant effect on pH was observed with any treatment. The results suggested that these food grade antimicrobials have the potential to be used in antimicrobial active packaging applications for beef products.

Fabrication and Antibacterial Effects of Polycarbonate/Leaf Extract Based Thin Films

We have reported the preparation and antibacterial activities of leaf extract incorporated polycarbonate thin films to improve the antibacterial characteristics of host polycarbonates (PCs). Crude extracts of Azadirachta indica, Psidium guajava, Acalypha indica, Andrographis paniculata, and Ocimum sanctum were prepared by maceration using Dimethylformamide as solvent. The leaf extracts (LE) were incorporated into the PC matrix by solution blending method, and the thin films were fabricated by Thermally Induced Phase Separation (TIPS) technique. The antibacterial activities of the as-prepared films were evaluated against E. coli and S. aureus by disk diffusion method. The inhibitory effects of the PC/LE films are higher for S. aureus than the E. coli, but pristine PC film did not exhibit any remarkable antibacterial characteristics. Further, the model fruit (Prunus) studies revealed that the PC/LE films retained the freshness of the fruits for more than 11 days. This study demonstrates that the PC/LE films have excellent antibacterial activities; thus, the films could be promising candidate for active antibacterial packaging applications.

Physicochemical and antimicrobial properties of sodium alginate/gelatin-based silver nanoformulations

In the present investigation, synthesis of silver nanoparticles (AgNPs) has been successfully carried out in a very simple and cost-effective manner by reducing Ag+ ions in sodium alginate solution and further stabilizing the colloidal mixture with gelatin solution. The ultraviolet–visible (UV–vis) spectra were in excellent agreement with the nanostructure morphology obtained from dynamic light scattering transmission electron microscopy and their size distributions. Increase in precursor concentration was found to promote agglomeration of AgNPs. Antibacterial assays revealed that the nanoformulations were more active against Gram-negative bacteria. Swelling studies of the hydrogel films demonstrated a rapid increase in water uptake. However, an increase in swelling % was observed with decreasing AgNP content. The use of biocompatible materials such as sodium alginate and gelatin not only provides green and economic attributes to this piece of research work but, at the same time, also opens up possibilities of using the nanoformulations in wound dressings, active packaging and several other biomedical applications.

Novel natural phenolic compound-based oxygen scavenging system for active packaging applications

An oxygen scavenging system containing a natural phenolic compound, pyrogallol with sodium carbonate, was developed and analyzed as a possible oxygen scavenger. The effect of several parameters, including the amount of pyrogallol and sodium carbonate, relative humidity and storage temperature, on the oxygen scavenging capability were investigated. The initial, glass vial headspace oxygen content (%) of 21.1 % (v/v) decreased to 0.26 % after 8 days of storage at room temperature when the oxygen scavenging system used a 1:1 (w/w) ratio of pyrogallol (250 mg) and sodium carbonate (250 mg). Both pyrogallol and sodium carbonate were required for optimum oxygen scavenging, otherwise the oxygen scavenging ability decreased. The oxygen content (%) decreased further to 6.55 % (v/v) when the amount of sodium carbonate decreased from 250 to 166 mg, which yielded a 2:1 ratio. In the present study, pyrogallol (250 mg) and sodium carbonate (250 mg) had highest oxygen scavenging capacity of 51.81 mL O2/g and an oxygen scavenging rate of 6.48 mL O2/g day. The oxygen absorption kinetics rate of pyrogallol and sodium carbonate confirmed that the material has good efficiency for use as an oxygen scavenger. Results indicated that the pyrogallol based oxygen scavenging system with moisture activation can be used as an effective oxygen scavenger for low water activity food packaging applications.

Rice straw nanofibrillated cellulose films with antimicrobial properties via supramolecular route

Novel antimicrobial nanofibrillated cellulose (NFC) with new optical and good tensile strength properties was prepared through supramolecular modification of TEMPO-oxidized NFC by Cu-, Zn-, and Fe–terpyridine metal complexes (M–Tpy). The prepared terpyridine-modified NFC (NFC–M–Tpy) derivatives were characterized using transmission electron microscopy (TEM), Fourier transform infrared (FTIR), and elemental analysis. Films casted from aqueous suspensions of NFC–M–Tpy plasticized by glycerol were made and characterized using X-ray diffraction (XRD), tensile strength, porosity, water vapor permeability, and antimicrobial properties testing. Attaching the different M–Tpy moieties to NFC resulted in increasing tensile strength and Young’s modulus, decreasing porosity and water vapor permeability (WVP), and imparted NFC antimicrobial properties against Gram-positive bacteria (Staphylococcus aureus), Gram-negative bacteria (Escherichia coli), as well as yeast (Saccharomyces cervisiae). NFC–Cu–Tpy film showed higher antimicrobial properties than NFC–Zn–Tpy and NFC–Fe–Tpy films while the other properties tested showed independence on the type of metal center in the terpyridine complex. The NFC–Cu–Tpy was used for coating bagasse paper sheets and tensile strength, burst strength, water vapor permeability, porosity, and water sorption of coated paper sheets were tested. NFC–Cu–Tpy coating improved tensile strength properties and reduced porosity, WVP, and water absorption of coated paper sheets more than in case of using NFC. The prepared nanocellulosic materials can find potential applications in active packaging and healthcare paper products.

Nanocomposite films based on cellulose acetate/polyethylene glycol/modified montmorillonite as nontoxic active packaging material

Nontoxic biodegradable nanocomposite as active packaging applications.

Performance of Nonmigratory Iron Chelating Active Packaging Materials in Viscous Model Food Systems.

Many packaged food products undergo quality deterioration due to iron promoted oxidative reactions. Recently, we have developed a nonmigratory iron chelating active packaging material that represents a novel approach to inhibit oxidation of foods while addressing consumer demands for "cleanˮ labels. A challenge to the field of nonmigratory active packaging is ensuring that surface-immobilized active agents retain activity in a true food system despite diffusional limitations. Yet, the relationship between food viscosity and nonmigratory active packaging activity retention has never been characterized. The objective of this study was to investigate the influence of food viscosity on iron chelation by a nonmigratory iron chelating active packaging material. Methyl cellulose was added to aqueous buffered iron solutions to yield model systems with viscosities ranging from ∼1 to ∼10(5) mPa·s, representing viscosities ranging from beverage to mayonnaise. Iron chelation was quantified by material-bound iron content using colorimetry and inductively coupled plasma-optical emission spectrometry (ICP-OES). Maximum iron chelation was reached in solutions up to viscosity ∼10(2) mPa·s. In more viscous solutions (up to ∼10(4) mPa·s), there was a significant decrease in iron chelating capacity (P < 0.05). However, materials still retained at least 76% iron chelating capacity. Additionally, the influence of different food hydrocolloids on the performance of nonmigratory iron chelating active packaging was characterized. Methyl cellulose and carrageenan did not compete with the material for specific iron chelation (P > 0.05). Materials retained 32% to 45% chelating capacity when in contact with competitively chelating hydrocolloids guar gum, locust bean gum, and xanthan gum. This work demonstrates the potential application of nonmigratory iron chelating active packaging in liquid and semi-liquid foodsto allow for the removal of synthetic chelators, while maintaining food quality.

Natural copaiba oil as antibacterial agent for bio-based active packaging

This study investigates the antibacterial properties of the natural oil from Copaifera multijuga which was embedded in bio-based materials, to be used in active packaging applications. For this purpose, the naturally extracted copaiba oil was first characterized by gas chromatography and thermogravimetry. Its antibacterial properties were evaluated and confirmed against gram-positive bacteria (Bacillus subtilis). The copaiba oil was incorporated into two bio-based materials: (i) paper and (ii) poly(lactic acid), PLA, films. This incorporation was made following two strategies: either at the surface, thanks to a coating process, or in the bulk, through impregnation (paper samples) or by film casting (PLA films). The antibacterial tests confirmed activity against B. subtilis in paper with a copaiba oil content of approximately 20wt%. For the PLA films, the same amount showed satisfactory results against the same bacteria. To the best of our knowledge, it is the first time that copaiba oil has been incorporated on paper sheets and plastic films, with the confirmation of the maintenance of the effective antibacterial properties. The materials developed in this work through simple procedures have great perspective to be used as biodegradable packaging with bactericide effect, to improve the shelf life of food products.

Application of Vacuum Cooling Technology and Active Packaging to Improve the Quality of Chinese Kale

This research studied the effect of vacuum cooling combined with active packaging on the quality of Chinese kale from an initial core temperature of 22-25°C to a final core temperature of 4±1°C. The study results illustrate that the optimum condition for Chinese kale under the vacuum cooling process is obtained with the best parameters at a holding time of 5 minutes. The total cycle time was 17 minutes and the electrical energy consumption was 0.017 kWh, with a resulting electricity cost of THB 0.06 per kilogram of Chinese kale. Precooled Chinese kale was then packaged in six different types of packaging material, namely perforated polyethylene, polypropylene and active packag- ing with different oxygen transmission rates (OTR): 10,000-12,000, 12,000- 14,000, 8,000-16,000cc m -2 day -1 and stored at 4±1°C. Subsequently, the effect of vacuum cooling with active packaging on the quality of Chinese kale was investigated. The results showed that the Chinese kale precooled under vacuum cooling process with the best active packaging (M1) had a longer storage life of 14 days compared to the normal storage life of non-precooled Chinese kale packaged in perforated polyethylene (Doi Kham bag) of 3 days.

Nanotechnology development in food packaging: A review

In this article, current nanocomposite technologies to enhance the mechanical and barrier properties of synthetic polymers and biopolymers for food packaging are reviewed. In addition, nanotechnology developments targeting active packaging applications are discussed, including antimicrobial, oxygen scavenging, and shelf-life extension of food. Nanotechnologies that are currently being exploited for the development of intelligent packaging with enhanced communication function are presented, focusing mainly on oxygen, humidity and freshness indicators. Nanostructured coatings that enhance the barrier properties of packaging films are reviewed. And finally, the perspectives of nanotechnology in food packaging applications are discussed. • Opportunities of nanotechnology in existing packaging systems are discussed. • Nanocomposite and its enhancement of mechanical and barrier properties are reviewed. • Nanotechnology developments targeting active packaging applications are reviewed. • Nanotechnology developments targeting intelligent packaging are reviewed. • Nanotechnology is an important tool to overcome existing challenges in packaging.

Controlled release of nisin from HPMC, sodium caseinate, poly-lactic acid and chitosan for active packaging applications

Biodegradable polymers with distinct composition can be used as antimicrobial carriers. To judge their relative efficiency as antimicrobial carriers, release rates of fluorescently labeled nisin Z from hydroxypropyl methylcellulose (HPMC), chitosan (CTS), sodium caseinate (SC) and polylactic acid (PLA) films were evaluated at 4 and 40°C in water–ethanol solution. Nisin diffusion coefficient (D) indicated that DCTS<DPLA<DSC<DHPMC. Temperature increase significantly increased nisin release from SC and HPMC films due to glass transition and hydrophilic nature. Partition coefficients (K) followed the same trend but were below 1, except for HPMC at 40°C, which implies that, at equilibrium, a lower amount of nisin was liberated in water–ethanol solution. A higher antibacterial effect against Listeria monocytogenes CIP 82110 and Staphylococcus aureus CIP 4.83 was observed with HPMC and SC films containing nisin due to strong interactions (hydratation) between the medium and the film. However, HPMC, CTS, SC packaging films could progressively release nisin to sustain an anti-bacterial effect and can be favorably used for prolonging shelf life of packed food.

Zein‐based ultrathin fibers containing ceramic nanofillers obtained by electrospinning. II. Mechanical properties, gas barrier, and sustained release capacity of biocide thymol in multilayer polylactide films

ABSTRACTThe combination of electrospinning technology and nanomaterials such as nanoclays can synergistically lead to novel materials with enhanced properties and functionalities for their usage in passive and active packaging applications. Part I of this work was focused on the development of ultrathin zein fibers containing nanoclays, which were oriented along the fiber axis and increased the thermal properties. Part II presents the use of the hybrid fibers as passive and active components in multilayer packaging structures. The hybrid fibers are incorporated in poly(lactic acid) films via a two‐step process: Electrospinning and compression molding. The composites thus produced presented improved mechanical and barrier properties than the unfilled material. The natural biocide extract thymol is then incorporated in the coating, and its sustained release properties are shown. The antimicrobial capacity of the hybrid fibers was also determined against foodborne bacteria. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40768.