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The separation sheets for fruit leather are traditionally made of plastic film or wax paper, which not only leads to environmental issues but also is inconvenience to consumers. This study evaluated edible fruit leather separation sheets using food polymers, including hydroxypropyl methyl cellulose (HPMC) and incorporation of cranberry pomace water extract (CPE) for providing natural fruit pigment, flavor, and phenolics. HPMCCPE film was then further improved by incorporating hydrophobic compound (oleic acid, OA) and vitamin E (VE) via cellulose nanocrystal (CNC) Pickering emulsion (CNCP) for enhancing film hydrophobicity and nutritional benefit, respectively. The CNCP–HPMCCPE film exhibited reduced water vapor permeability (∼0.033 g mm/m2 d Pa) compared to HPMCCPE film (∼0.59 g mm/m2 d Pa) and had the least change in mass and moisture content when wrapping fruit leather for up to 2 weeks of ambient storage. The fruit leather wrapped by CNCP–HPMCCPE film showed lower weight change than those by films without CNCP due to low mass transfer between film and fruit leather. CNCP resulted in controlled release of VE into a food simulating solvent (ethanol). The developed colorful and edible fruit leather separation sheet satisfied the increased market demands on sustainable food packaging. Practical Application: Colorful and flavorful edible films made of edible polymers, fruit pomace water extract, and emulsified hydrophobic compounds with vitamin E were created. The films have the satisfactory performance to replace the conventional fruit leather separation sheet made of plastic or wax paper. The edible films can be eaten with packaged fruit leather for not only reducing packaging waste but also providing convenience and nutritional benefit to consumers. These functional edible films may also be utilized to package other food products for promoting packaging sustainability and nutritional benefit. [ABSTRACT FROM AUTHOR]

Whey protein concentrate (WPC) has been widely studied as a biodegradable bio‐based packaging material in the food industry. In this study, different whey protein films were obtained through physical, chemical, enzymatic, and composite modifications. The molecular structure, micro‐morphology, mechanical properties, barrier properties, and other characteristics of the films were evaluated. The results illustrated that the thickness of WPC with composite modification increased and the transmittance decreased, but the mechanical properties and barrier properties were more prominent. The WPC film prepared by physical modification combined with transglutaminase has the best film‐forming effect, the tensile strength (TS) was 5.45 MPa, the elongation at break (EAB) was 25.19%, the WVP was 5.53 g·mm/m2·hr·kPa, and the Oxygen permeability (OP) was 1.83 meq/K, and its microstructure was and uniform. In addition, based on the the results of SDS‐PAGE and Fourier transform infrared spectroscopy (FTIR), the intermolecular and intramolecular interactions of various modification methods on WPC were studied, thus contributing to analyze the properties of the film. This study provides theoretical basis and technical support for the industrial production of protein‐based films. [ABSTRACT FROM AUTHOR]

Abstract: The molding of food products causing health risks is a main problem in the food industry. In this study, as an alternative solution for preventing mold growth, an antifungal edible film was developed by incorporating Williopsis saturnus var. saturnus (0; 3; 7; and 9 logs CFU/cm2) into whey protein concentrate (WPC) based films. Antifungal properties of the films against Penicilium expansum and Aspergillus niger were analyzed using the disc diffusion method. Physical (barrier, solubility, color), mechanical (tensile strength and percent elongation) properties of the films as well as the survival of W. saturnus in the film were assessed during 28 days of storage at 23 °C. According to the results, the viability of W. saturnus (7 and 9 logs CFU/cm2) in WPC films stored for 28 days under vacuum or non‐vacuum decreased to 36% and 60%, respectively. In addition, films containing W. saturnus decreased the viability of P. expansum and A. niger by 29% and 19%, respectively. Adding yeast did not change the tensile strength (P > 0.05), but significantly decreased % elongation and increased water vapor and oxygen permeability and water solubility (P < 0.05). In conclusion, this study showed that the developed films may be useful for inhibiting mold growth on foods. [ABSTRACT FROM AUTHOR]

Solid sodium alginate was dissolved into chicken stock in order to give a final alginate concentration of 0.9 percent (w/v). Calcium ions present in chicken stock were enough to induce ionic gelation. After drying, Fourier transform infrared spectroscopy, thickness and mechanical properties of films obtained were determined. Calcium alginate-chicken stock films were heated at 130 °C for different times between 0 and 15 min. Mechanical and optical studies, differential scanning calorimetry, visual aspect and scanning electron microscopy were carried out to describe physicochemical properties of heat treated films. Heating developed a maroon ochre color and increased the brittleness (crispness) of the films related to the intensity of the treatment. Differential scanning thermometry and study on appearance of the films suggested that Maillard reactions may be responsible for the observed changes. Maillard reactions mainly occurred between reducing sugar monomers and free amino groups of gelatin peptides present in the chicken stock, and between alginate and gelatin peptides to a lesser extent. In addition, the plasticizing effect of fat added with chicken stock was also studied. These studies suggest a potential use of heat treated chicken stock films as a substitute of roasted chicken skin. [ABSTRACT FROM AUTHOR]

No prior research has investigated whether the cold plasma treatment (CPT) resulted in the formation of toxic compounds. Therefore, this study carried out the experiment to check the safety of edible films treated with cold plasma by examining their acute and subacute oral toxicity in a rat model. Single-dose acute (5000 mg/kg body weight) and 14-d subacute (1000 mg/kg body weight/day) oral toxicity of cold plasma-treated edible films was assessed for male and female Sprague-Dawley (SD) rats. Rats administered 5000 mg/kg of edible film did not show the signs of acute toxicity or death after 14 d of observation. Similarly, no signs of acute toxicity or death were recorded during 14 d in rats administered 1000 mg/kg/day of edible film treated with cold plasma. Although changes in the levels of several blood components (hematocrit, hemoglobin, bilirubin, creatinine, and aspartate aminotransferase) of samples were observed, the changes compared to the control were considered to be toxicologically irrelevant as their levels were within normal physiological ranges. Macroscopic analysis showed there were no changes in color or texture of representative liver sections of SD rats following the oral administration of edible films with CPT (F-CP) or without CPT (F-NT). The results demonstrate that the cold plasma-treated edible film possessed very low toxicity, suggesting that CPT does not generate harmful by-products in the edible film. [ABSTRACT FROM AUTHOR]

To identify the significant contribution of intermolecular hydrogen bonds of starch molecules to the film structure formation, pH of film-forming solutions was adjusted and also various salts (NaCl, CaCl2, CaSO4, and K2SO4) were mixed into the glycerol-plasticized pea starch film. The film made from pH 7 possessed the highest tensile strengthat- break (2 times) and elastic modulus (4 to 15 times) and the lowest elongation-at-break compared with those of the films made from acid and alkali environments. The pH 7 film also has the highest film density and the lowest total soluble matter. At the level of 0.01 to 0.1 M of CaSO4 and 0.1 M of K2SO4 in a kilogram of starch, the water solubility of the film increased, while chloride salts slightly lowered the solubility. NaCl and CaSO4 reduced water vapor permeability (WVP), while CaCl2 slightly increasedWVP at 0.01 and 0.06 M concentrations, and K2SO4 significantly increased WVP at 0.03 and 0.15 M. Presence of salts increased tensile strength (5 to 14 times than the control films) and elastic modulus (35 to 180 times) of starch film at 0.01 to 0.03 M of CaSO4 and K2SO4. Elongation-at-break increased significantly as salt concentration increases to an optimal level. However, when the concentration exceeded above the optimal level, the E of starch films decreased and showed no significant difference from the control film. Overall, the addition of salts modified physical and mechanical properties of pea starch films more than pH adjustment without any salt addition. [ABSTRACT FROM AUTHOR]

Thyme essential oil (TEO) and apple skin polyphenols (ASP) are natural compounds considered as generally recognized as safe by FDA, with biological effects against bacteria and fungi. This work aimed to evaluate physical and antimicrobial properties of açaí edible films formulated with TEO and ASP at 3% and 6% (w/w) individually or combined at 3% (w/w) each. Physical properties studied include mechanical resistance, water vapor permeability (WVP), color, and thermal resistance. Antimicrobial activity against Listeria monocytogenes was determined using the overlay diffusion test. Addition of ASP resulted in improved mechanical properties. TEO at 6% (w/w) resulted in increased elongation. ASP films had significant higher WVP than control film. ASP films were lighter and had more red color than other films. Incorporation of ASP resulted in improved film thermal stability, whereas TEO caused rapid thermal decomposition. Presence of clusters was observed on the surface of films. Addition of ASP resulted in a smother surface, whereas addition of TEO led to the formation of crater-like pits on the film surface. Açaí edible film incorporated with 6% (w/w) TEO presented the highest antimicrobial activity. However, both antimicrobials are necessary in the açaí films in order to obtain edible films with suitable physical-mechanical properties. The results of the present study showed that TEO and ASP can be used to prepare açaí edible films with adequate physical-mechanical properties and antimicrobial activity for food applications by direct contact. Practical Application Developed açaí edible films presented antimicrobial activity against L. monocytogenes and good physical-mechanical properties, showing the potential use of açaí edible films in food preservation. [ABSTRACT FROM AUTHOR]

The incorporation of essential oils and nanotechnology into edible films has the potential to improve the microbiological safety of foods. The aim of this study was to evaluate the effectiveness of pullulan films containing essential oils and nanoparticles against 4 foodborne pathogens. Initial experiments using plate overlay assays demonstrated that 2% oregano essential oil was active against Staphylococcus aureus and Salmonella Typhimurium, whereas Listeria monocytogenes and Escherichia coli O157:H7 were not inhibited. Two percent rosemary essential oil was active against S. aureus, L. monocytogenes, E. coli O157:H7, and S. Typhimurium, when compared with 1%. Zinc oxide nanoparticles at 110 nm were active against S. aureus, L. monocytogenes, E. coli O157:H7, and S. Typhimurium, when compared with 100 or 130 nm. Conversely, 100 nm silver (Ag) nanoparticles were more active against S. aureus than L. monocytogenes. Using the results from these experiments, the compounds exhibiting the greatest activity were incorporated into pullulan films and found to inhibit all or some of the 4 pathogens in plate overlay assays. In challenge studies, pullulan films containing the compounds effectively inhibited the pathogens associated with vacuum packaged meat and poultry products stored at 4 °C for up to 3 wk, as compared to control films. Additionally, the structure and cross-section of the films were evaluated using electron microscopy. The results from this study demonstrate that edible films made from pullulan and incorporated with essential oils or nanoparticles may improve the safety of refrigerated, fresh or further processed meat and poultry products. [ABSTRACT FROM AUTHOR]

This research evaluated the antimicrobial efficacy of pullulan films containing caraway essential oil (CEO). The films were prepared from a 10% of pullulan, containing from 0.12% to 10.0% of CEO. The composition of the CEO was analyzed with the use of gas chromatography. The antimicrobial activity of the CEO was evaluated with the method of serial microdilutions, and the films containing CEO-with the agar diffusion method against selected Gram-negative, Gram-positive bacteria, and fungi. The structure of the film surface and its cross-section were analyzed using a scanning electron microscope (SEM). Analyses were also carried out to determine the efficacy of a pullulan coating with 10% CEO on baby carrots experimentally inoculated with Salmonella enteritidis, Staphylococcus aureus, Saccharomyces cerevisiae, or Aspergillus niger and stored at a room temperature for 7 d. At a concentration of 0.12%, CEO inhibited the growth of all the tested microorganisms. Pullulan films containing 8% to 10% of CEO were active against all tested microorganisms. Populations of S. aureus on carrot samples were reduced by approximately 3 log CFU/g, while those of A. niger and S. cerevisiae by, respectively, 5 and 4 log CFU/g, after 7 d of storage. S. enteritidis was the most resistant among the tested species, since it was not significantly reduced after 7 d of storage. At the end of storage, samples treated with pullulan-caraway oil coating maintained better visual acceptability than control samples. Results of this study suggest the feasibility of applying a pullulan film with incorporated CEO to extend the microbiological stability of minimally processed foods. [ABSTRACT FROM AUTHOR]

An edible composite film was prepared from an emulsion system based on chitosan and virgin coconut oil (VCO). The effect of incorporation of VCO was evaluated at various concentrations and the optimum concentration was chosen based on resultant changes in the properties of the film. Addition of VCO in film forming solution resulted in increase in film thickness and marginal reduction in film transparency. Compatibility of VCO with chitosan was better at lower concentration of VCO as indicated by the microstructure of composite film in scanning electron micrographs. Phase separation was evident at higher level of oil incorporation and the optimal oil/chitosan ratio was determined to be at 0.5 to 1 mL/g chitosan. Furthermore, chemical interaction took place between VCO and chitosan as revealed by Fourier transform infrared spectroscopy data. Even though control chitosan films exhibited superior gas barrier properties, composite film with optimum VCO concentration revealed better mechanical and moisture sorption properties. [ABSTRACT FROM AUTHOR]

Edible biopolymer films were developed from gelatin extracted from trout skin (TSG) using thermal protein denaturation conditions and plasticizer (glycerol) concentration as variables. The amino acid composition of the TSG, elastic modulus, viscous modulus, and the viscosity of film-forming solutions, and tensile properties, water vapor permeability, solubility in water, and color of TSG-based films were determined. A 6.8% (w/w, wet basis) trout skin-extracted gelatin solution containing 9, 17, or 23% (w/w, dry basis) glycerol was heated at 80, 90, or 100 °C for 30, 45, or 60 min to prepare a film-forming solution. TSG can be characterized as a gelatin containing high contents of methionine and aspartic acid. The gelation temperature of the film-forming solution was 7 °C and the solution was subjected to heating to form a stable matrix for a film. Increased heating time of the film-forming solution reduced the film solubility ( P < 0.05). Heating at 90 °C for 30 min was suggested as the requirement for film formation. As the concentration of glycerol in the film increased, film strength and moisture barrier properties decreased, while film stretchability increased ( P < 0.05). Trout skin by-products can be used as a natural protein source for fabricating biopolymer films stable at ambient conditions with certain physical and moisture barrier properties by controlling thermal treatment conditions and glycerol concentrations. Practical Application: The fishing industry produces a significant amount of waste, including fish skin, due to fish processing. Trout skin waste has potential value as a protein source that can be used to form biopolymer edible films for packaging low and intermediate water activity food products, and thus may have practical applications in the food industry, which could be one way to cut waste disposal in the trout processing industry. [ABSTRACT FROM AUTHOR]

The use of antimicrobial edible film is proposed as a means of improving food safety and extending the shelf-life of food systems by controlling the release of antimicrobials on food surfaces. In this work we first selected and studied 8 different essential oils (EOs) from plants, namely, oregano, clove, tea tree, coriander, mastic thyme, laurel, rosemary, and sage as natural antimicrobials against 2 gram-positive bacteria ( Listeria innocua and Staphylococcus aureus) and 2 gram-negative bacteria ( Salmonella enteritidis and Pseudomona fragi) by using the agar disk diffusion method. EOs from oregano, clove, and tea tree produced the largest surfaces of inhibition against the growth of the 4 bacterial strains tested. Second and following the assessment of compatibility, stable antimicrobial edible films based on whey protein isolate (WPI) with increasing concentrations (0.5% to 9%) of the 8 EOs were developed and tested for antimicrobial activity against the same gram-positive and gram-negative bacteria. WPI-edible films incorporating oregano or clove EO were found to have the most intense inhibitory effect of microbial growth. The bacterial strain gram-negative P. fragi presented the less susceptibility to the effect of those films. Moreover, only the edible films based on these 2 EOs were active against all 4 studied microorganisms. On the other hand, the edible films incorporating tea tree, coriander, mastic thyme, laurel, rosemary, or sage EOs even at high concentrations (7% to 9%) did not cause any antimicrobial effect against the pathogens S. aureus or S. enteritidis. Practical Application: Potential applications of this technology can introduce direct benefits to the food industry by improving safety and microbial product quality. The results of this research have direct application in the food industry with potential applications in various foodstuffs, including meat and poultry products where the control of spoilage bacteria such as P. fragi throughout their chilled storage or the improvement of food safety by controlling pathogens such as S. enteritidis are topics of particular interest for the industry. [ABSTRACT FROM AUTHOR]

Edible films from squid mantle muscle plasticized with different plasticizers were stored at 25 °C, 50% RH before the determination of physical properties. The results showed that tensile strength significantly increased ( P < 0.05) upon the storage time, especially for the film plasticized with glucose, while there was no significant change ( P≥ 0.05) in elongation at break of all plasticized films. Water vapor permeability of glucose-plasticized film significantly decreased ( P < 0.05) during storage, while there was only a slight change in those with glycerol, sorbitol, and fructose. Redness and yellowness of the films became significantly higher ( P < 0.05) during storage, especially for the films plasticized with fructose and glucose. SDS-PAGE and protein solubility in SDS solution showed a possibility of protein aggregation throughout the storage. From these results, it is suggested that the changes in physical properties of the films were caused by the progress of Maillard reaction. Practical Application: In this study, squid mantle muscle was used as an edible film-forming material. By mixing with Na-citrate, squid mantle muscle possessed the ability to form transparent films with an excellent UV barrier property. Glycerol was found to be the most effective and stable plasticizer for the films. Edible films represent an option for the utilization of discarded squid during the fishing process. [ABSTRACT FROM AUTHOR]

To manufacture red algae (RA) film, we used various plasticizers such as glycerol, sorbitol, sucrose, fructose, and polypropylene glycol (PPG), and then determined the mechanical properties of the RA films. The tensile strength (TS), elongation at break (E), and water vapor permeability (WVP) of the films containing various plasticizers ranged between 0.43 to 9.10 MPa, 10.93% to 47.17%, and 1.28 to 1.42 ng m/msPa, respectively. RA films containing fructose as a plasticizer had the best mechanical properties of all the films evaluated. Incorporation of nanoclay (Cloisite Na and 30B) improved the mechanical properties of the films. RA film with 3% Cloisite Na had a TS of 10.89, while RA film with 30B had a TS of 10.85 MPa; these films also had better E and WVP values than the other RA films evaluated. These results suggest that RA/nanoclay composite films are suitable for use as food packaging materials. Edible RE/nanoclay composite films prepared in the present investigation can be applied in food packaging. [ABSTRACT FROM AUTHOR]

Fruit and vegetable skins have polyphenolic compounds, terpenes, and phenols with antimicrobial and antioxidant activity. These flavoring plant essential oil components are generally regarded as safe. Edible films made from fruits or vegetables containing apple skin polyphenols have the potential to be used commercially to protect food against contamination by pathogenic bacteria. The main objective of this study was to evaluate physical properties as well as antimicrobial activities against Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella enterica of apple skin polyphenols at 0% to 10% (w/w) concentrations in apple puree film-forming solutions formulated into edible films. Commercial apple skin polyphenol powder had a water activity of 0.44 and high total soluble phenolic compounds and antioxidant capacity (995.3 mg chlorogenic acid/100 g and 14.4 mg Trolox/g, respectively). Antimicrobial activities of edible film containing apple skin polyphenols were determined by the overlay method. Apple edible film with apple skin polyphenols was highly effective against L. monocytogenes. The minimum concentration need to inactive L. monocytogenes was 1.5%. However, apple skin polyphenols did not show any antimicrobial effect against E. coli O157:H7 and S. enterica even at 10% level. The presence of apple skin polyphenols reduced water vapor permeability of films. Apple skin polyphenols increased elongation of films and darkened the color of films. The results of the present study show that apple skin polyphenols can be used to prepare apple-based antimicrobial edible films with good physical properties for food applications by direct contact. [ABSTRACT FROM AUTHOR]

Edible films were manufactured from rapeseed oil extraction residues. To prepare rapeseed protein (RP) films, various concentrations of plasticizers and emulsifiers were incorporated into the preparation of a film-forming solution. The optimal conditions for the preparation of the RP film were 2% sorbitol/0.5% sucrose as plasticizer and 1.5% polysorbate 20 as an emulsifier. In addition, RP blend films were prepared. Gelidium corneum or gelatin was added to improve the physical properties of the RP film, and the highest tensile strength value of the films was 53.45 MPa for the 3% RP/4% gelatin film. Our results suggest that the RP-gelatin blend film is suitable for applications in food packaging. Edible RP films prepared in the present investigation can be applied in food packaging. [ABSTRACT FROM AUTHOR]

The objectives of this research were to characterize the mechanical and barrier properties of sweetpotato starch (SPS)-based film (SPSF) and to investigate the antimicrobial activity of SPSF containing origanum oil (OG) against foodborne pathogenic bacteria. The SPSF was fabricated with the SPS extracted from commercial sweetpotato roots. Tensile strength (TS), percent elongation at break (E), and water vapor permeability (WVP) were determined to characterize the SPSF fabricated with selected SPS concentrations, plasticizers, and the concentrations of plasticizers. The agar diffusion assay was used to determine the antimicrobial activity of SPSF containing selective concentrations of OG against Salmonella Enteritidis, Escherichia coli O157:H7, and Listeria monocytogenes. The SPSF fabricated with 2.5% SPS exhibited the greatest TS (4.58 MPa). The TS, E, and WVP of SPSF plasticized with 40% sorbitol exhibited 7.96 MPa, 77.92%, 0.212 ng m/m S Pa, respectively. Therefore, the SPSF fabricated with 2.5% SPS and 40% sorbitol was determined as the optimum film. The antimicrobial activity of the SPSF containing OG increased as the concentration of OG increased. And the SPSF containing OG exhibited greater inhibitory effects against the gram-negative bacteria such as S. Enteritidis and E. coli O157:H7 than the gram-positive L. monocytogenes. The greatest antimicrobial activity was observed against S. Enteritidis when the SPSF containing 2% OG was applied, and the maximum square of zone width was 18.43 mm. [ABSTRACT FROM AUTHOR]

The effect of the beeswax, Span 20, and glycerol content on qualities of soybean-protein-isolate edible films was evaluated. Beeswax and Span 20 were selected to improve qualities of soybean-protein-isolate films from 11 emulsifiers. The content of beeswax, Span 20, and glycerol was further optimized by response surface analysis. The optimal composite emulsifier was beeswax (1.87% of soybean protein-isolate), Span 20 (10.25% of soybean protein-isolate), and glycerol (29.12% of soybean protein-isolate) with tensile strength of 908 MPa, percentage elongation at break of 25.8%, water vapor permeability of 19.2 g/m·d·MPa, and oxygen permeability of 0 cm3/m·d·MPa. The quality of soybean-protein-isolate films incorporated with the optimal composite emulsifier was 2.34 times higher than that of the control. Furthermore, the disulfide bond content of soybean-protein-isolate films showed a positive correlation with their quality, which provided a simple and rapid way to rank quality of soybean-protein-isolate films. Therefore, our result will not only give an instruction to soybean-protein-isolate-film production, but also give a simple and rapid way to rank film qualities. Practical Application: Our results give the optimal composite emulsifiers for the soybean-protein-isolate-film production. The soybean-protein-isolate films based on the optimal composite emulsifiers show their tensile strength of 908 MPa, percentage elongation at break of 25.8%, water vapor permeability of 19.2 g/m·d·MPa, and oxygen permeability of 0 cm3/m·d·MPa, being stronger than the control. Moreover, our results give a simple and rapid way to rank film qualities, because the disulfide bond content of soybean-protein-isolate films showed a positive correlation with their quality. Hence, the disulfide bond content was an indicator to rank qualities of soybean-protein-isolate films. [ABSTRACT FROM AUTHOR]

The antiplasticization effect of plasticizers (that is, polyols and monosaccharides) in starch films was investigated. Pea starch films were plasticized by various polyols and monosaccharides at the levels of 0% to 25% (w/w, plasticizer/starch). After 14 d of storage at 50% relative humidity, the crystallinity of pea starch films increased with increasing concentration of plasticizers from 0% to 20%. Accordingly, moisture content, water vapor permeability, oxygen permeability, and elongation decreased with increasing plasticizer concentration from 0% to 20%, showing the antiplasticization effect. The addition of plasticizers above 20% reduced the crystallinity of starch films, consequently showing the plasticization effect. The results showed that the addition of the plasticizers facilitated the crystallization of the polymer chains through the antiplasticization phenomenon at the concentration range below 15%. Above 20%, plasticizers performed the conventional plasticization effect. Each plasticizer had different critical concentration where the antiplasticization was converted to plasticization. [ABSTRACT FROM AUTHOR]

We prepared an edible film of Gelidium corneum (GC) containing carvacrol as an antimicrobial and antioxidative agent. The GC film containing carvacrol significantly decreased the WVP, while TS and %E values were increased, compared to the film without carvacrol. Increasing amounts of an antimicrobial agent increased antimicrobial activity against Escherichia coli O157:H7 and Listeria monocytogenes. Application of the film to ham packaging successfully inhibited the microbial growth and lipid oxidation of ham during storage. Our results indicate that GC film can be a useful edible packaging material for food products, and the incorporation of carvacrol in the GC film may extend the shelf life. [ABSTRACT FROM AUTHOR]