Light Barrier Properties Research Articles

Encapsulation of Tea Polyphenol in Zein through Complex Coacervation Technique to Control the Release of the Phenolic Compound from Gelatin–Zein Composite Film

Green tea polyphenol (TP) was encapsulated in zein and fabricated into a gelatin–zein composite film by complex coacervation. Transglutaminase (TG) crosslinking was employed to obtain a compact structural orientation of the film to prolong the release of bioactive compounds. The encapsulation efficiency of zein and the TP release rate from the composite film were investigated. The retention rate was over 30% and 80% after film fabrication and storage, respectively. Crosslinking decreased the diffusion coefficient by half, thus improving the release of TP from the film. The antioxidant properties were satisfactory after discharge from the film detected by DPPH/ABTS scavenging. The value of crosslinking degree (~60%) and increased molecular weight of the protein were investigated by SDS-PAGE, indicating the compatibility of TP and TG treatment. According to physicomechanical findings, the TG2TP1 film exhibited the best characteristics. Tensile strength and water solubility properties were ameliorated by the TG treatment of TP-encapsulated films compared to the control film. TG and TP-loaded gelatin–zein composite film had better thermal stability than the control film. Moreover, the TP loading reduced the transparency value and improved the light-barrier properties of the film. The films showed significant antimicrobial activities against two food-borne bacteria, including Staphylococcus aureus BCTC13962 and Escherichia coli BCRC10675. The result obtained shows that the encapsulation of TP and TG treatment may be used to fabricate gelatin–zein composite film with controlled release of phenolic compounds for active packaging applications.

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.

Development of Smart Films of a Chitosan Base and Robusta Coffee Peel Extract for Monitoring the Fermentation Process of Pickles.

Smart film is widely used in the field of food packaging. The smart film was prepared by adding anthocyanin-rich Robusta coffee peel (RCP) extract into a chitosan (CS)-glycerol (GL) matrix by a solution-casting method. By changing the content of RCP (0, 10%, 15% and 20%) in the CS-GL film, the related performance indicators of CS-GL-RCP films were studied. The results showed that the CS-GL-RCP films had excellent mechanical properties, and CS-GL-RCP15 film maintained the tensile strength (TS) of 16.69 MPa and an elongation-at-break (EAB) of 18.68% with RCP extract. CS-GL-RCP films had the best UV-vis light barrier property at 200-350 nm and the UV transmittance was close to 0. The microstructure observation results showed that CS-GL-RCP films had a dense and uniform cross section, which proved that the RCP extract had good compatibility with the polymer. In addition, the CS-GL-RCP15 film was pH-sensitive and could exhibit different color changes with different pH solutions. So, the CS-GL-RCP15 film was used to detect the fermentation process of pickles at 20 ± 1 °C for 15 days. The pickles were stored in a round pickle container after the boiling water had cooled. The color of the CS-GL-RCP15 film changed significantly, which was consistent with the change of pickles from fresh to mature. The color of the smart film changed significantly with the maturity of pickles, and the difference of ΔE of film increased to 8.89 (15 Days), which can be seen by the naked eye. Therefore, CS-GL-RCP films prepared in this study provided a new strategy for the development of smart packaging materials.

Use of cellulose microfibers from olive pomace to reinforce green composites for sustainable packaging applications.

To valorize abundant, unexploited, and low-cost agro-industrial by-products, olive pomace is proposed as a sustainable and renewable raw material for cellulose microfibers (CMFs) production. In this study, CMFs were extracted from olive pomace using alkaline and bleaching treatments and characterized in terms of morphological, structural, and thermal properties. Afterward, the reinforcing capability of microfibers was examined using carboxymethyl cellulose (CMC) as a polymer matrix by the solvent casting process. The effects of CMF loading (1%, 3%, 5%, and 10%) on the composites' mechanical, physical, morphological, and thermal properties were assessed. CMF incorporation led to a decrease in moisture content (MC), water solubility (WS), and water vapor permeability (WVP) and an increase in tensile strength (TS), stiffness and transparency values, and thermal stability of CMC films. Increasing CMF content to 5%, increased the TS and elasticity modulus by 54% and 79%, respectively, and reduced the WVP and light transmissivity at 280 nm, by 22% and 47%, respectively. The highest water, moisture, light barrier, and mechanical properties of composites were reached at 5% CMFs.

Regulating structure and properties of gelatine edible film through oxidized poly(2-hydroxyethyl acrylate) crosslinking

Regulating the structure and properties of gelatine edible films through aldehyde-type crosslinkers is a highly promising approach. In the present study, oxidized poly(2-hydroxyethyl acrylate) (OP) with different aldehyde contents and relative molecular weights was successfully prepared and used for crosslinking modification of gelatine edible films to regulate the material structure and properties. The introduction of OP enhanced the UV light barrier property and the hydrophobicity of the pure gelatine film. Moreover, the tensile strength and flexibility of the gelatine films were significantly improved by OP. The results indicated that aldehyde content and the relative molecular weights of OP played a vital role in regulating the structural and mechanical properties of the edible gelatine films. OP crosslinking is an effective approach in regulating structure and properties of gelatine edible films, and the OP modified gelatine films have the potential to be used as a food packaging material.

Colorimetric and antioxidant films based on biodegradable polymers and black nightshade (Solanum nigrum L.) extract for visually monitoring Cyclina sinensis freshness.

In this study, colorimetric and antioxidant films were developed by using cassava starch (CS), κ-carrageenan (KC) and black nightshade fruit anthocyanins (BNA), and their physical and functional properties were investigated. We found BNA presented significant color changes in different pH solutions. And incorporation of BNA significantly increased the tensile strength, water vapor permeability, UV-vis light barrier property, pH-sensitivity and antioxidant activity of CS-KC film. Results of structural characterization indicated that H-bonds were formed between CS, KC and BNA in films and the film compactness was significantly improved by BNA incorporation. Results of the rheological property assay showed the films had high apparent viscosity with an obvious shear-thinning behavior. When applied to monitoring the quality change of Cyclina sinensis, CS-KC-BNA films exhibited significant color changes with the degradation process of C. sinensis qualities. Our results suggested CS-KC-BNA films could be utilized in smart packaging in food industry.

Layer-by-layer assembly of sustainable lignin-based coatings for food packaging applications

Packaging plays a critical role in ensuring food safety and shelf life by protecting against e.g., moisture, gases, and light. Polyethylene (PE) is widely used in food packaging, but it is mainly produced from non-renewable resources and it is an inefficient oxygen and light barrier. In this study, the layer-by-layer (LbL) assembly of a sustainably produced lignin-based polymer (EH) with polyethylenimine (PEI) or chitosan (CH) was used to fabricate (partially or fully) bio-based coatings with the aim of improving barrier properties of PE films. The charge density of EH was calculated using a polyelectrolyte titration method and the hydrodynamic diameters of EH, PEI and CH were determined by Dynamic Light Scattering (DLS). LbL assembly was monitored in situ via Quartz Crystal Microbalance with Dissipation (QCM-D) and Stagnation Point Adsorption Reflectometry (SPAR). PE films were coated with a variable number of PEI/EH or CH/EH bilayers (BL) using an immersive LbL assembly method. Coated films were studied in terms of light-blocking ability, wettability, thermal behaviour, surface structure, as well as oxygen and water vapor barrier properties. QCM-D and SPAR data showed a stepwise multilayer formation and strong interactions between the oppositely charged polymers, with PEI/EH coating having a greater amount of deposited polymer compared to CH/EH coating at the same number of BL. Overall, light barrier properties and wettability of the coated films increased with the number of deposited bilayers. Coated PE films maintained the overall thermal behaviour of PE. A number of BL of 20 was found to be the most promising based on the studied properties. Selected samples showed improved oxygen and water vapor barrier properties, with PEI/EH coating performing better than CH/EH coating. Taken altogether, we demonstrated that a novel and sustainable lignin-based polymer can be combined with PEI or CH to fabricate (partially or fully) bio-based coatings for food packaging.

Comparative physical, antioxidant, and antimicrobial properties of films prepared by dissolving chitosan in bioactive vinegar varieties

Solvent casting following the dissolution of chitosan in aqueous acetic acid is the most widely used method for preparing chitosan films. In this study, an economical and practical way is proposed to improve the physicochemical properties of chitosan films by using vinegar varieties both as solvents and as bioactive additives to improve the properties of the films. Chitosan films were prepared by dissolving chitosan in pomegranate, grape, apple, and hawthorn vinegar. Vinegar contains bioactive phenolics and different organic acids together with acetic acid, depending on the main raw material from which it is obtained. The films' mechanical, optical properties, antioxidant and antimicrobial activities were compared with each other and with the chitosan film prepared by dissolving chitosan in acetic acid. The antioxidant and antimicrobial properties of chitosan films prepared with vinegar increased. The use of vinegar as a solvent increased the UV light barrier properties of the films. Improved antimicrobial, antioxidant, optical, and elastic properties of films prepared by dissolving chitosan in vinegar varieties are promising in applications of these films as potential and economic food packaging materials.

Utilising N‐glutaryl chitosan‐based film with butterfly pea flower anthocyanin as a freshness indicator of chicken breast

AbstractA novel indicator film was produced with N‐glutaryl chitosan (ChGA) as a matrix and butterfly pea flower anthocyanin (BPA) as a dye. The synthesis of ChGA was achieved by the reaction of chitosan (Ch) and glutaric anhydride (GA), which resulted in the structural alteration of Ch, with carboxylic groups being present in ChGA. The ChGA–BPA film demonstrated higher sensitivity to changes in pH, a more compact structure, and more hydrophilic properties compared with Ch‐BPA film. The ChGA–BPA film demonstrated antioxidant and antimicrobial activity, as well as an enhanced biodegradable property. Further characterisation showed ChGA–BPA film possessed ultraviolet visible (UV–Vis) light barrier properties and was non‐toxic to cells. Lastly, when tested as packaging, the films underwent a visible colour changes from blue to yellowish‐green as chicken breast was stored at various temperatures, which correlated with an increase in nitrogen compounds, indicating the potential of this film as a smart packaging solution to monitor the freshness of chicken breast.

Pectin from plantain peels: Green recovery for transformation into reinforced packaging films

Plantain peels as agro-waste are generated in the millions of tons per year with no profitable management strategies. On the other hand, the excessive use of plastic packaging threatens the environment and human health. This research aimed to address both problems via a green approach. High-quality pectin was recovered from plantain peels via an enzyme-assisted and ethanol-recycling process. The yield and galacturonic acid (GalA) content of the recovered low methoxy pectin was 12.43% and 25.0%, respectively, when cellulase was added at 50 U per 5 g peel powder, with a significantly higher recovery rate and purity than the pectin products extracted with no cellulase (P ≤ 0.05). The recovered pectin was further integrated and reinforced with beeswax solid-lipid nanoparticles (BSLNs) to fabricate films as a potential alternative packaging material to single-use plastics. The reinforced pectin films showed improved light barrier, water resistance, mechanical, conformational, and morphological properties. This study presents a sustainable strategy to transform plantain peels into pectin products and pectin-based packaging films with broad applications.

Waste Orange Peels as a Source of Cellulose Nanocrystals and Their Use for the Development of Nanocomposite Films.

To date, approximately 30-50% of food is wasted from post-harvesting to consumer usage. Typical examples of food by-products are fruit peels and pomace, seeds, and others. A large part of these matrices is still discarded in landfills, while a small portion is valorized for bioprocessing. In this context, a feasible strategy to valorize food by-products consists of their use for the production of bioactive compounds and nanofillers, which can be further used to functionalize biobased packaging materials. The focus of this research was to create an efficient methodology for the extraction of cellulose from leftover orange peel after juice processing and for its conversion into cellulose nanocrystals (CNCs) for use in bionanocomposite films for packaging materials. Orange CNCs were characterized by TEM and XRD analyses and added as reinforcing agents into chitosan/hydroxypropyl methylcellulose (CS/HPMC) films enriched with lauroyl arginate ethyl (LAE®). It was evaluated how CNCs and LAE® affected the technical and functional characteristics of CS/HPMC films. CNCs revealed needle-like shapes with an aspect ratio of 12.5, and average length and width of 500 nm and 40 nm, respectively. Scanning electron microscopy and infrared spectroscopy confirmed the high compatibility of the CS/HPMC blend with CNCs and LAE®. The inclusion of CNCs increased the films' tensile strength, light barrier, and water vapor barrier properties while reducing their water solubility. The addition of LAE® improved the films' flexibility and gave them biocidal efficacy against the main bacterial pathogens that cause foodborne illness, such as Escherichia coli, Pseudomonas fluorescens, Listeria monocytogenes, and Salmonella enterica.

Development of active packaging films based on collagen/gallic acid-grafted chitosan incorporating with ε-polylysine for pork preservation

Active packaging films (CCG/PL) based on collagen, functionalized chitosan with gallic acid (GA), and ε-polylysine (ε-PL) (different amount of 2.5, 5, and 10 wt%, respectively) were developed to prolong the shelf life of pork stored at 4 °C. Fourier transform infrared analysis indicated that hydrogen bonds had formed between collagen molecules and GA moieties, and there were no strong interactions between polymers and ε-PL. SEM images showed that the cross-sections of CCG/PL films were compact but aggregation of ε-PL occurred when ε-PL content reached 10 wt%. CCG/PL films possessed strong light barrier properties with the UV light transmittance lower than 4% in the range of 200–350 nm. Compared with CC film, the DPPH free radical scavenging rate was significantly increased by 84.35% due to the synergistic effect of GA and ε-PL on antioxidant activity. CCG/PL film containing 5 wt% ε-PL had excellent antimicrobial activity against S. aureus as well as good tensile strength (65.34 MPa). The wrapping of CCG/PL film with 5 wt% ε-PL effectively retarded the lipid oxidation of pork and inhibited the growth of bacterium during the storage time, and the shelf life of pork was prolonged by approximately 5 days than that of pork in polyethylene film.

Innovative design of bio-functional Persian gum-based edible films by incorporating crocin and cinnamaldehyde: Free versus single and double emulsion fabrication techniques

The objective of this research was to fabricate a new generation of bio-functional Persian gum-based films via the co-delivery of crocin and cinnamaldehyde. Different loading strategies using single W/O and O/W emulsions and W 1 /O/W 2 double emulsions were used to find how the distribution of bioactives in the film suspension can modify their physicochemical and biological properties compared to those prepared with the free forms of bioactives. The incorporation of emulsion structures significantly decreased the surface tension of film-forming solutions, but their viscosity remained relatively constant. The good compatibility between Persian gum and cinnamaldehyde/crocin was confirmed by FTIR and XRD. The optical, mechanical, and microstructural attributes of the films were more affected by the incorporation of the free form of bioactives. The UV–Vis light barrier property and hydrophobicity of the film were improved after incorporating single and double emulsions. However, the greater stability of bioactives within double emulsion against different pH (2 and 7) and temperatures (25 and 75 °C) produced more superior antibacterial and antioxidant activities. Furthermore, the homogenous distribution of double emulsion in the film matrix led to more resistant and extensible films. • Persian gum-based film was fortified with co-delivery of crocin and cinnamaldehyde. • Comparison was made between free and single and double emulsions loading techniques. • Mechanical and optical properties were more affected by free forms of bioactives. • Double emulsion strategy led to superior antibacterial and antioxidant activities. • Emulsion-based films were transparent but with high UV/Vis barrier properties.

Edible composite films based on chitosan/guar gum with ZnO[sbnd]NPs and roselle calyx extract for active food packaging

The present study aimed to prepare and characterize edible composite films. The edible composite films were made from a mixture of guar gum/chitosan with the loading of zinc oxide nanoparticles (ZnONPs) and roselle calyx extract (RCEx). The incorporation of RCEx and ZnONPs improved the antioxidant and mechanical properties of films. Based on yield of bioactive compounds obtained by the UAE method was used for the development of ZnONPs and the edible composite film. The Cross-section microstructure of the films showed that the films were dense and compact. Although the incorporation of RCEx decreased the transparency of the films, it enhanced the UV–Vis light barrier properties. The tensile strength, elongation at break, and solubility of CS/GG film, CS/GG/RCEx and, CS/GG/RCEx/ZnONPs film was found to be (35.74 MPa, 54.24 MPa and, 69.42 MPa), (15.56%, 12.27% and, 9.69%), and (67.23%, 59.41%, and 61.35%) respectively. Water vapor permeability (WVP) of the films was decreased from 4.68 to 4.06 (g /m2.day.kPa) after the addition of zinc oxide nanoparticles into the films, respectively. RCEx and ZnONPs incorporated films showed the higher antioxidant activity than control film, 11.52%, 42.55% and, 68.15% respectively. This study showed edible composite films incorporated ZnONPs and RCEx have promising potential for applications in active food packaging in the future.

A double-layer smart film based on gellan gum/modified anthocyanin and sodium carboxymethyl cellulose/starch/Nisin for application in chicken breast

In order to overcome this challenge of poor stability of natural anthocyanins in intelligent packaging materials, roselle anthocyanin (RA) was first modified by acetic acid, and then a double-layer smart indication antimicrobial film was developed using modified roselle anthocyanin (MRA)-gellan gum (GG) as the inner layer and sodium carboxymethyl cellulose (CMC)-starch (ST)-Nisin as the outer layer. UV spectra revealed that acetic acid was successfully grafted onto RA, which dramatically improved their thermal stability, antioxidant capabilities, photostability, and pH stability. The bilayer films were successfully prepared, as revealed by scanning electron microscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction measurements. In comparison to GG-MRA and CMC-ST-Nisin films, the water content, water solubility, mechanical characteristics, water vapor barrier, oxygen barrier, and hydrophobicity of GG-MRA@CMC-ST-Nisin films were significantly enhanced. The presence of the outer layer films significantly enhanced the UV–vis light barrier, opacity, antioxidant and antibacterial properties of the inner layer films. When the films were applied to chicken breast, it was found that the indicator films not only monitored the freshness of the chicken in real-time but also that the GG-MRA film and the double-layer film were effective in extending the shelf life of the chicken by 1 and 2 days, respectively, compared to the control group.

Incorporation of oxidized debranched starch/chitosan nanoparticles for enhanced hydrophobicity of corn starch films

Starch films have superior advantages owing to the renewability and low cost of starch; however, their strong inherent hydrophilic character greatly limits their practical application. This study aimed to improve the hydrophobicity of corn starch films by adding a new type of covalently formed, oxidized debranched starch/chitosan nanoparticles (SC-NPs). SC-NPs were obtained by a Schiff-base crosslinking reaction between the aldehyde group of dialdehyde debranched starch and the amino group of chitosan. Corn starch films reinforced with SC-NPs were obtained using a casting method. A mass ratio of dialdehyde debranched starch and chitosan of 3–5 yielded mainly spherical nanoparticles ranging from 50 to 150 nm in diameter determined by transmission electron microscopy. The water contact angle (WCA) of the pure starch film was only 19.4°, whereas the WCA values of the films reinforced with 3 % SC-NPs were greater than 70°, indicating that SC-NPs efficiently improved the hydrophobicity of corn starch films. The ultraviolet and visible light barrier property of starch films with 3 % SC-NPs were significantly enhanced in comparison with pure starch film. The water vapor permeability, water solubility, and swelling ratio were markedly lower in films with 3 % SC-NPs than in neat starch films.

Effects of purple passion fruit peel extracts on characteristics of Pouteria campechiana seed starch films and the application in discernible detection of shrimp freshness

In this work, the film-forming potential of Pouteria campechiana seed starch (PCSS) and the effects of purple passion fruit (Passiflora edulis) peel extracts (PPPAEs) on the properties of films were examined for the first time. The structural analyses showed that PPPAEs had great compatibility with PCSS without altering the chemical structure of PCSS films. The addition of PPPAEs meaningfully enhanced the ultraviolet–visible light barrier properties. The mechanical properties of the PCSS films were also remarkably influenced due to the introduction of PPPAEs, as confirmed by the increased elongation at break and decreased tensile strength. Moreover, the introduction of PPPAEs endowed the PCSS films with great antioxidant properties, as well as noticeable color change when subjected to the ammonia environment and pH alternation. The PCSS/9 PPPAEs films were utilized to monitor shrimp freshness, and obvious color changes from light pinkish brown to green could be observed as shrimp freshness was reduced during storage. The PCSS-based films presented great biodegradability, as confirmed by the test result that all systems have wholly integrated into the soil and nearly disappeared after 14 days of burial. In summary, PPPAEs were capable of bestowing PCSS films with desirable properties, and the fabricated PCSS/PPPAEs composite films could potentially be used for the visible detection of the freshness of meat and aquatic products rich in proteins.

Developments of pH responsive biodegradable monitoring film based on poly(vinyl alcohol) incorporated with Sappan heartwood extract for food packaging applications

<abstract> <p>The major problem leading to substantial waste in the food industry is the spoilage of food products during transportation and storage periods. Consequently, the scope of this research focuses on the development and preparation a pH responsive monitoring films based on biodegradable materials of poly(vinyl alcohol) (PVA) and natural colorant extract from <italic>Caesalpinia sappan</italic> L. heartwood (SP). These monitoring films were prepared by a solution casting method and the film stability was improved by crosslinking with citric acid (CA). The red tone of monitoring film without CA was observed, while the crosslinked monitoring film showed a yellow color, which occurs from the structural change of brazilin (structure presenting in SP) to brazilein under acidic conditions. From the SEM and FTIR results, the monitoring film showed high compatibility between phases, improvements in light barrier properties and good WVTR performance. The tensile strength and elongation at break were slightly increased. For pH responsive properties, the monitoring films showed a high response with NH<sub>3</sub> gas detection with the change in color from a yellow tone to a red tone. These results indicated that the monitoring films have potential to be applied as food packaging for meat, fish, pork, chicken, and other foods that generate ammonium gas during spoilage. Therefore, these high stable, and non-toxic biodegradable PVA films that incorporated with SP extract and crosslinked by CA have the potential to be used for food spoilage detection in packaging.</p> </abstract>

Effect of Repeated Contact to Food Simulants on the Chemical and Functional Properties of Nano ZnO Composited LDPE Films for Reusable Food Packaging

The effect of repeated contact with food simulants on the properties and functionality of zinc oxide (ZnO) in nanocomposite films was investigated to examine possible safety hazards from the point of view of long-term use as food packaging. Low-density polyethylene (LDPE) embedded with 5 wt% nano-ZnO was immersed in distilled water, 50% ethanol, 4% acetic acid, and n-heptane. The cycle of immersion-rinse-dry was repeated up to 40 times for same sample under constant condition. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), field emission-scanning electron microscopy (FE-SEM), and UV-Vis spectroscopy analyses were performed to identify the changes in the chemical and functional properties of the nanocomposite film. Acetic acid had the greatest impact on the LDPE-ZnO nanocomposite films, while other food simulants caused little change. A new carboxylate bond was formed by the reaction of ZnO with acetic acid, as evidenced by the FTIR spectra. In addition, XRD and XAS confirmed the phase changes of nano-ZnO into zinc salts such as zinc hydroxy acetate or zinc acetate dihydrate. Furthermore, the light barrier property of the nanocomposite film drastically decreased, owing to the change in the bandgap of ZnO and film morphology.

Novel bioactive films integrated with Pickering emulsion of ginger essential oil for food packaging application

Biocomposite films based on carboxymethyl cellulose (CMC)/polyvinyl alcohol (PVOH) added ginger essential oil (GEO) via Pickering emulsion (PE) method were fabricated and applied for preservation of bread. The films were assessed for their physicochemical, morphological, mechanical, thermal, antioxidant, and microbial properties. SEM imaging indicated encapsulation of GEO spherical droplets into PE. The films exhibited lower tensile strength, higher elongation at break, and thickness after adition of GEO PE. ATR/FT-IR spectroscopy demonstrated the formation of some interaction between polymer matrix and GEO PE. Packaging of bread slices with GEO integrated biocomposite films extended the shelf life of bread from 4 to 30 days. Remarkably, the GEO-loaded CMC/PVOH films showed excellent UV and light barrier properties, high antioxidant and antimicrobial activities, which make them suitable for food packaging application.