Promising Food Packaging Material Research Articles

Novel antimicrobial biodegradable composite films as packaging materials based on shellac/chitosan, and ZnAl2O4 or CuAl2O4 spinel nanoparticles

ZnAl2O4 and CuAl2O4 spinel nanoparticles were prepared by a modified Pechini method and used with the natural chitosan (CS) and shellac (SH) polymers to form novel composite membranes as promising food packaging materials. The selection of ZnAl2O4 and CuAl2O4 spinel nanoparticles was based on their antibacterial characteristics, availability, and economy. Using a straightforward and adaptable solution mixing and casting method, the bio-composites were created. The mechanical, physical, antibacterial, homogeneity and air permeability properties of composite films were investigated. The film structure was evaluated in terms of component interactions using FTIR spectra. The addition of 10% SH increased the tensile strength, percentage strain at maximum load, Young’s modulus, and burst strength by 114–101%, 3.6–8.4, 103–119, and 179–153% for low and middle M.wt./CS respectively. Chitosan/shellac-CuAl2O4 composite has superior properties compared to ZnAl2O4 composite. In general, 0.05% spinel provides a composite having better qualities than that of 0.1 additions. Middle M.wt. chitosan provides a composite with superior properties compared to that of low M.wt. The incorporation of ZnAl2O4 or CuAl2O4 enhanced the thermal stability of the SH/CS composite. ZnAl2O4 provides superior thermal stability than CuAl2O4. When shellac/CS film structure is treated with the previously indicated ZnAl2O4 or CuAl2O4 formulation, the % swelling decreases along with an increasing in the gel fraction. The antimicrobial assessment using inhibition zone diameter and shake flask methods showed that a composite of 1:9 shellac/chitosan/0.05% of CuAl2O4 exerted the highest Gram-positive antibacterial activity against B. mycoides (21 mm), and C. albicans (22 mm). So, these enhancements make chitosan/shellac/ZnAl2O4 or CuAl2O4 composite films a good alternative to producing food packaging materials.

Impacts of tannin inclusion on fabrication, characterization and antioxidant activity of sodium alginate-silk fibroin-tannin films and their application on fresh-cut apple packaging

The current work aimed to formulate sodium alginate-silk fibroin-tannin films to preserve fresh-cut apples. In this experiment, tannins (0.1, 0.2, 0.3, 0.4, 0.5%) were added to the sodium alginate (1.05%)-silk fibroin (3.38%) films by casting method. Fourier transform infrared spectroscopy, molecular docking was employed to investigate the presence of hydrogen bonding among the sodium alginate, silk fibroin and tannins. Scanning electron microscopy showed surfaces and cross-sections became porous and rough with increasing tannins concentration. The films were characterized by mechanical properties, light barrier properties, water solubility and water vapor permeability. The value of maximum tensile strength and minimum elongation at break was 0.99 MPa and 91.38% respectively for the sodium alginate-silk fibroin-tannin films with 0.3% (w/v) tannins. The percentage of light transmittance of sodium alginate-silk fibroin-0.3% tannin films was 54.45% at 500 nm. The water solubility rate of sodium alginate-silk fibroin-0.3% tannin films at pH 8.0 was improved 54.42% compared with that at pH 1.2. The value of minimum water vapor permeability of the sodium alginate-silk fibroin-0.3% tannin films was 1.49 × 104 g mm/cm2∙s∙Pa. The sodium alginate-silk fibroin-tannin films showed higher scavenging ability of 2,2-diphenyl-1-picrylhydrazyl and superoxide anion radical than sodium alginate-silk fibroin films. The sodium alginate-silk fibroin-tannin films had antibacterial activity against Staphylococcus aureus and Escherichia coli. The apples packed with the sodium alginate-silk fibroin-0.3% tannin films did not rot during seven days. The fabricated films of sodium alginate-silk fibroin-tannin in this study are biodegradable and they may be a promising food packaging material.

Preparation and characterization of chitosan/bacterial cellulose composite biodegradable films combined with curcumin and its application on preservation of strawberries

We provided in detail a simple and environmentally-friendly method to prepare a biodegradable composite film using chitosan (CS) and bacterial cellulose (BC) with excellent dispersion. CS was grafted onto BC by Schiff base reaction firstly, and then obtained the nano-sized fibrils by ultrasonic dispersion process (CS-OBC). Different concentrations of curcumin (Cur, 0 %, 0.1 %, 0.3 %, 0.5 %, and 0.7 %, w/v) were incorporated into CS-OBC composite films prepared with optimal film-forming parameters. Mechanical and antioxidant properties, including moisture content, water solubility, and contact angles, were evaluated to determine the effects of Cur addition on the composite films (CS-OBC-Cur). It was found that Cur addition increased the hydrophobicity and oxygen permeability of the film, and that the CS-OBC-0.5%Cur active film exhibited excellent barrier properties, hydrophobicity, and mechanical properties. In addition, polyphenol release was retarded when the active film was in a simulated fat system. The film showed superior preservation of strawberries compared with ordinary PE film and significantly slowed the oxidation of edible oils. These results suggest that CS-OBC-Cur films are a promising food packaging material.

Fabrication of cellulose/rectorite composite films for sustainable packaging

In order to reduce the environmental pollution caused by plastic packaging, the development of biodegradable high-performance packaging materials has become a research hotspot. Cellulose is a promising food packaging material, but it usually lacks sufficient ultraviolet (UV) shielding property and mechanical strength. In this work, rectorite microplates were incorporated into the cellulose matrix by a facile blending method to fabricate the composite films. The structure and properties of the composite films were characterized by FT-IR, X-ray diffraction, scanning electron microscopy, UV–vis and mechanical properties test etc. The results indicated that rectorite microplates were uniformly distributed in the cellulose matrix. The blocking percentages for UVA and UVB for the cellulose/rectorite composite film with 14 wt% rectorite content (RCRF-14) could reach as high as 97.8 % and 96.0 %, respectively, showing a good UV shielding property. Meanwhile, the addition of rectorite obviously improved the mechanical properties and decreased the water vapor and oxygen permeabilities of the cellulose film, showing a potential application as a sustainable food packaging material.

Characterization of biodegradable food packaging films prepared with polyamide 4: Influence of molecular weight and environmental humidity

AbstractThe development of biodegradable packaging materials focuses on their barrier properties and mechanical properties, which are critical parameters for food protection. Synthetic biodegradable material polyamide 4 (PA4) may offer outstanding capacities for packaging due to its rigid molecular structure. The current study originally reveals the various physical properties of PA4 films and explores the influence of its internal structure, molecular weight, and external environment, environmental humidity, on its performance to provide further guidance for PA4 application. PA4 (Mη = 18,000 g/mol) films showed tensile strength (TS) of 47.5 ± 1.3 MPa, elongation at break (EB) of 228% ± 30%, oxygen permeability of 7.83 ± 3.32 × 10−17 cm3 m−1 s−1 Pa−1, and water vapor permeability of 4.34 ± 0.06 × 10−11g m−1 s−1 Pa−1. The TS and EB of PA4 improved slightly with increasing molecular weight, while the barrier characteristic remained unchanged. The moisture adsorption capabilities of PA4 films were similar to natural hydrophilic polymers. The mechanical characteristic of PA4 changed from brittle to ductile with the increase in relative humidity. Overall, PA4 can be considered to be a promising food packaging material since it presented better mechanical and oxygen barrier properties than those of commercial food packaging polymers.

A novel functionalized food packaging film with microwave-modified konjac glucomannan/chitosan/citric acid incorporated with antioxidant of bamboo leaves

The health hazards associated with the use of plastic films to preserve food require the development of active films from non-toxic and antioxidant rich biological sources. In this study, a novel functional food packaging material was developed by microwave modification of a composite film made of konjac glucomannan (KGM)/chitosan (CTS)/citric acid with the addition of the antioxidant of bamboo leaves (AOB). The effects of different contents of the AOB (0.1%, 0.2%, 0.3% and 0.4%, w/v) on the structure, physical properties and antioxidant activity of KGM/CTS/citric acid films were systematically studied. The results from Fourier transform infrared spectroscopy and atomic force microscopy showed that the components in the KGM/CTS/citric acid film had good compatibility due to the hydrogen bonds among them and furthermore the AOB was evenly distributed in the composite film. The addition of AOB significantly improved the oxidation resistance, anti UV–Vis and mechanical properties of the materials. Moreover, when the AOB content was 0.2%, the film had the best barrier property and the maximum elongation at break. Therefore, with all the meaningful improvement, the newly developed KGM/CTS/citric acid biological film might be used as promising food packaging materials in the future.

Carboxymethyl chitosan incorporated with gliadin/phlorotannin nanoparticles enables the formation of new active packaging films

Advanced carboxymethyl chitosan (CMCS) based functional films were fabricated by involving some amounts of gliadin/phlorotannin nanoparticles (GPNPs) using a solution casting method. GPNPs were synthesized by an antisolvent precipitation approach, and they presented a spherical morphology with a mean diameter of 145.30 ± 2.06 nm. The effect of GPNPs concentration on the structural, physical, antioxidant and antimicrobial properties of CMCS-GPNPs (C-G) functional films was evaluated. It was found that the added GPNPs were homogeneously distributed over the whole CMCS matrix, allowing to reduce the free volume of the nanocomposite matrix and subsequently improve the physical properties of the final film (evidenced by mechanical and water barrier properties). FT-IR spectra indicated the intermolecular interactions, such as hydrogen bonds and electrostatic interaction, within the matrix of the nanocomposite films were increased. Impressively, the anti-ultraviolet properties, antioxidant activity and antimicrobial behaviors of the as-formed C-G functional films were greatly enhanced compared to the pure CMCS film. All these results suggested that our as-prepared C-G nanocomposite films could be a promising food packaging material.

高抗菌性聚乙烯醇/Ag@MOF食品包装膜的制备与表征

Four different polyvinyl alcohol (PVA) based food packaging films (PVA/Ag@MOF, PVA/H2PYDC, PVA/Ag, PVA) were prepared by flow-casting method in order to analyze the feasibility of silver based organic framework (Ag@MOF) for food packaging. Their mechanical properties, thermodynamic properties, water barrier, antibacterial and cytotoxicity were studied. The results show that compared with PVA and PVA/H2PYDC films, the addition of Ag@MOF improves the mechanical properties of the films, and the maximum tensile strength of the films is increased to 36.21 MPa. Compared with PVA, PVA/H2PYDC and PVA/AgNPs films, the addition of Ag@MOF enhances the thermal stability of the films. Compared with PVA and PVA/H2PYDC films, the rigid structures of AgNPs and Ag@MOF prevent the diffusion of water and improve the performance of water resistance. The antibacterial activity of PVA/Ag@MOF membrane against Staphylococcus aureus and Escherichia coli was much higher than that of AgNPs and H2PYDC composite films, and it had low cytotoxicity. Therefore, PVA/Ag@MOF film is a promising food packaging material, which can reduce the interference of environmental microorganisms on food with low cytotoxicity, and improve food safety and storage cycle.

Fabrication and characterization of polylactic acid coaxial antibacterial nanofibers embedded with cinnamaldehyde/tea polyphenol with food packaging potential

Polylactic acid (PLA) is a promising food packaging material with biocompatible, nontoxic and biodegradable. In order to reduce the deterioration of aquatic products caused by microorganisms, PLA coaxial nanofiber films with cinnamaldehyde (CMA), tea polyphenol (TP) and its composite as core materials were prepared by using coaxial electrospinning technology. Its microscopic morphology and structure were characterized separately, and its thermal stability, wettability and mechanical properties were determined. The antibacterial activity and antibacterial mechanism of nanofiber films were studied with Shewanella putrefaciens (S. putrefaciens) which is the dominant spoilage of aquatic products as the target of action. The results show that the CMA/TP (m/m = 2:5)-PLA coaxial nanofibers have small diameter, uniform distribution, smooth surface, no pores and fracture. At the same time, the film has strong hydrophobicity, good thermal stability and mechanical properties. Its antibacterial performance is better than that of single-core nanofiber films, which effectively destroys the cell membrane of S. putrefaciens, increases the permeability of cell membrane, and interferes with the synthesis and expression of its protein. The coaxial nanofiber films with CMA, TP and its composite as core material can be used as a fresh-keeping material with antibacterial properties, and has potential application value in the field of food preservation.

Physicochemical and Antibacterial Evaluation of Poly (Vinyl Alcohol)/Guar Gum/Silver Nanocomposite Films for Food Packaging Applications

In this study, we prepared Poly (vinyl alcohol) (PVA)/Guar gum (GG) based nanocomposite films with a different weight ratio of silver nanoparticles (AgNPs) via in situ approach using GG itself as a reducing agent and PVA as a capping as well as stabilizing agent at room temperature. The in situ synthesized AgNPs in the PVA/GG matrix was confirmed by surface plasmon resonance (420–450 nm) and SEM-EDAX analysis. The average size of AgNPs was found to be 10 nm determined by XRD. The light transmittance is greatly influenced by the AgNPs. At an optimal concentration of AgNPs (6.8 mg), PVA/GG/Ag nanocomposite films showed improved tensile properties (Ts—23.93 MPa) and the water vapor transmission rate. The incorporation of AgNPs has significantly enhanced the hydrophobicity (~ 77%) as well as the thermal stability (~ 61.39%) of the PVA/GG film. The overall migration rate of the nanocomposite films with the three food simulants was shown significantly below the permitted limit of 10 mg/dm2. Further PVA/GG/Ag nanocomposite films showed a lower soil burial degradation rate than PVA/GG film and good antibacterial properties against environmental microorganisms such as S. aureus and E. coli bacteria. The results suggest that the prepared films can be used as promising food packaging materials.

Fabrication and characterization of the enhanced tensile strength xanthan/curdlan/gelatin blend films for food-packaging applications

Food packaging films are generally used to protect the food from outside harsh environment. Moreover, their main purpose is to prolong the shelf life and to maintain the freshness of food. Generally, plastic materials are widely used for this purpose. However, these plastic materials are causing a serious threats to our environment due to the problem of non-degradability. In this regard, biodegradable biopolymer materials are contemplated as an important alternative due to the environment friendly characteristics. However, the packaging films prepared from single pure polymers have been reported to possess very poor mechanical properties. Therefore, blending of two or three biopolymers is considered to synergistically improve the mechanical properties of biopolymer based films. In this work, we made a novel blended films of xanthan (X), curdlan (C) and gelatin (G) by mixing different ratios of all three polymers. After successfully preparing and optimization of these blended films, mechanical properties and moisture absorbance properties of all these films were determined. Based on the results, it was concluded that the highest tensile strength of 38.22±0.7 MPa was found in the T2 treatment of 20:20:60 ratio of X/C/G blend films. In addition, highest elongation at break of 18.92±0.5% was also found in the same rational of X/C/G blend films. Moreover, characterization techniques such as FT-IR and SEM analysis were also performed to analyze the structural properties of blend films. Finally, SEM micrographs indicated that all the blend films exhibited a uniform, smooth, homogenous and compact outer surface morphology. In short, this novel xanthan/curdlan/gelatin films resulted in improved mechanical properties of blend films, which confirm its suitability as promising food packaging material.

Development of Chitosan/Peptide Films: Physical, Antibacterial and Antioxidant Properties

Chitosan/peptide films were prepared by incorporating peptides (0.4%, w/v) from soy, corn and caseins into chitosan films. The presence of peptides significantly affected the physical, antibacterial and antioxidative properties of chitosan films. Among these films, those containing corn peptide showed the best water vapor barrier properties, and the tensile strength and elongation at break increased to 24.80 Mpa and 23.94%, respectively. Characterization of surface hydrophobicity and thermal stability suggested the strongest intermolecular interactions between corn peptides and chitosan. Moreover, films containing casein peptides showed the highest antibacterial activity and radical scavenging activity. The DPPH scavenging rate of films containing casein peptides reached 46.11%, and ABTS scavenging rate reached 66.79%. These results indicate the chitosan/peptide films may be promising food packaging materials.

Effect of Crystallinity on Water Vapor Sorption, Diffusion, and Permeation of PLA-Based Nanocomposites.

The effects of crystalline morphology and presence of nanoparticles such as cellulose nanofibers (CNFs), organically modified nanoclay (C30B), or a combination of both on water vapor sorption and diffusion in polylactide (PLA) were evaluated by a quartz spring microbalance (QSM). It was found that the large spherulite size induced by high-temperature processing leads to an increase in water sorption and a substantial reduction of diffusion with increasing crystallinity. Contrarily, small-sized spherulites, arising after low-temperature processing during solvent-casting, showed a different behavior with a slight decrease in both water vapor sorption and diffusion with increasing crystallinity. These observations suggest that solvent-casting at low temperatures should not be used to predict the properties a material will show after industrial-scale processing. From the analysis of the nanocomposite materials, it was concluded that nanoparticles affected the material′s properties not only by themselves but also by modifying the crystalline morphology. Interestingly, this led to CNF showing similar performance to C30B, decreasing water diffusivity (21 vs 27%) on isothermally crystallized materials despite its less favorable geometry. Additionally, the incorporation of 1 wt % CNF and C30B decreased water vapor transmission rate (WVTR) by 24% under an amorphous state but by 44% in a crystallized state, which makes hybrid CNF/C30B composites a promising food packaging material.

Preparation, characterization, and antibacterial properties of biofilms comprising chitosan and ε-polylysine

Of late, the demand for food-packaging materials, in particular, multifunction packaging materials that are biodegradable; antibacterial; have good mechanical and barrier properties; and are edible and transparent, has increased considerably. In this study, we prepared chitosan (CS)/ε-polylysine (PL) biofilms with different CS-to-PL ratios. We studied the preparation, mechanical properties, microstructures, thermal stability, transparency, water-vapor permeability, oil permeability, and antibacterial properties of the composite CS/PL biofilms. The results demonstrate that CS/PL biofilms are mechanically strong, have good thermal stability, high transparency, low water-vapor and oil permeability, and extensive antibacterial properties that act against Escherichia coli, Bacillus subtilis, and yeast. Therefore, we therefore conclude that CS/PL biofilms are promising food-packaging materials.

Synthesis and characteristics of konjac glucomannan films incorporated with functionalized microcrystalline cellulose

To development of konjac glucomannan (KGM) based films for use in food packaging is increasing because of environmental attraction, biodegradability and availability. The objective of this research was to prepare a facile approach for KGM based films. Polydopamine (PDA) functionalized microcrystalline cellulose (PFMC) were incorporated into a KGM matrix. The KGM/PFMC films were prepared by the solvent casting method. The surface morphology of the KGM/PFMC films were generated by scanning electron microscope (SEM) and atomic force microscope (AFM). The crystal structure and thermal ability of the film were generated by X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Rheological behavior, elemental and characteristic peak changes were developed by rheology, X-ray photoelectron spectroscopy (XPS) and fourier infrared spectroscopy (FT-IR). Incorporation of PFMC increased the mechanical properties owing to the high ratio (0.2 g) of PFMC and strong interactions with the KGM. Water vapor permeability (WVP) of the films were significantly decreased. Moreover, PFMC also gave KGM/PFMC films high thermal stability. The results suggest that that KGM/PFMC film is a promising food packaging material.

Preparation of chitosan-TiO2 composite film with efficient antimicrobial activities under visible light for food packaging applications

By incorporation of TiO2 nano-powder in chitosan, a chitosan-TiO2 composite film was prepared with efficient antimicrobial activity against food-borne pathogenic microbes and expected to be a promising food packaging material. Scanning electron microscopy analysis showed that the TiO2 nano-powder was successfully and uniformly dispersed into the chitosan matrix. TiO2 addition led to enhanced hydrophilicity, to better mechanical properties, and to decreased light transmittance in visible light region of the composite film. The chitosan-TiO2 film possessed efficient antimicrobial activity against four tested strains, i.e. Escherichia coli, Staphylococcus aureus, Candida albicans, and Aspergillus niger with 100% sterilization in 12h. It moreover provoked the leakage of cellular substances through damaged membrane. The prepared chitosan-TiO2 film was tested for packaging red grapes to prevent microbial infection and extend their shelf life. Results were positive, stressing the potential of the novel bio-nano composite film for food packaging applications.

Antimicrobial Efficiency of Edible Films in Food Industry

In this article, several applications of materials in food packaging and food safety are reviewed, including: polymers as high barrier packaging materials, natural substances as potent antimicrobial agents, and the efficiency of antimicrobial films in food industry. Active antimicrobial food packaging systems are supposed not only to passively protect food products against environmental factors, but also to inhibit or retard microbial growth on the food surface, extending the shelf life of products. Edible films can be incorporated into conventional food packaging systems with a dual purpose as an edible and antimicrobial component. Applications of antimicrobial films to fruits, vegetables and meat products have received increasing interest because films can serve as carriers for various natural antimicrobials that can maintain fresh quality, extend product shelf life and reduce the risk of pathogen growth. In the future, eco-friendly antimicrobial packaging films are promising food packaging materials because its biodegradability provides sustainable development for a modern community.In this article, several applications of materials in food packaging and food safety are reviewed, including: polymers as high barrier packaging materials, natural substances as potent antimicrobial agents, and the efficiency of antimicrobial films in food industry. Active antimicrobial food packaging systems are supposed not only to passively protect food products against environmental factors, but also to inhibit or retard microbial growth on the food surface, extending the shelf life of products. Edible films can be incorporated into conventional food packaging systems with a dual purpose as an edible and antimicrobial component. Applications of antimicrobial films to fruits, vegetables and meat products have received increasing interest because films can serve as carriers for various natural antimicrobials that can maintain fresh quality, extend product shelf life and reduce the risk of pathogen growth. In the future, eco-friendly antimicrobial packaging films are promising food packaging materials because its biodegradability provides sustainable development for modern community.

Soluble soybean polysaccharide: A new carbohydrate to make a biodegradable film for sustainable green packaging

Biodegradable edible films based on soluble soybean polysaccharide (SSPS), a new film-forming material, and three levels of glycerol (20%, 30% and 40%, w/w) as plasticizer, were developed and evaluated in terms of physical, mechanical, barrier and optical properties as well as their microstructure. SSPS-based films with a concentration of 20% glycerol possessed the lowest water vapor permeability. Increasing the glycerol content increased (P<0.05) values for elongation at break, but decreased (P<0.05) tensile-strength values. It was found that plasticizer concentration significantly affected the films’ glass-transition temperature; however, it had no significant effect on their melting point. Color measurement showed that increasing the glycerol concentration caused the b and L values to increase, while ΔE value decreased. These results were explained by the film's microstructure, which was analyzed by atomic force microscopy and scanning electron microscopy. The results indicated that SSPS could be a promising food-packaging material.