Vapor Barrier Research Articles

Controlling spheroid attachment improves pancreatic beta cell differentiation from human iPS cells.

Regenerative medicine using human induced pluripotent stem cells (hiPSCs) is available for treating type 1 diabetes; however, the efficiency and maturation of hiPSC differentiation into pancreatic beta cells requires improvement. Various protocols, including three-dimensional (3D) culture, have been developed to improve differentiation efficiency and maturation. Several methods for 3D culture have been reported; however, they require costly and complicated equipment, special materials, and complicated operations. To solve these problems, we developed a simple 3D culture method under static conditions using a cyclo-olefin polymer (COP) characterized by high moisture barrier properties, low surface energy, and hydrophobicity. Using this 3D method and our simple and low-cost protocol, we found that differentiation into the definitive endoderm (DE) was better when the spheroids were attached. Therefore, upon the addition of Y-27632, attached spheroids with unique shapes and cavities were formed, and the differentiation efficiency into DE increased. During DE differentiation, the attachment of spheroids to the substrate and their subsequent floating improved differentiation efficiency. We found that the amount of C-peptide in spheroids differentiated using COP dishes was greater than that in rotary culture. Furthermore, INSULIN was highly expressed in areas with low cell density, suggesting that the unique shape of the spheroids made from COP dishes improved differentiation efficiency. Our study suggests that a device-free, simple 3D culture method that controls spheroid attachment improves the efficiency of hiPSC differentiation into pancreatic beta cells.

Cellulose-Based Transparent Edible Antibacterial Oxygen-Barrier Coating for Long-Term Fruit Preservation.

Long-term preservation of fresh fruit and vegetables without a cold chain is a great challenge to food security because fruits and vegetables are highly vulnerable to poor storage conditions. Fruit spoilage is a complex biochemical process that involves many factors, including microbial reproduction, oxidation, metabolism, and H2O evaporation. Only the synergy of the multiple spoilage inhibition methods can achieve long-term freshness preservation. Herein, a multifunctional cellulose-based preservation coating with antibacterial, oxygen/water vapor barrier, and antioxidant properties is proposed, which is based on cellulose microgel (CMG) and prepared using multi-component composites with montmorillonite (MMT), cationic cellulose derivative (Cell-P+), and L-ascorbic acid (Vc). It has good wetting properties on fruits with different surfaces. This method can successfully preserve the long-term freshness of various fruits. This highly transparent, edible, and washable multifunctional cellulose-based fruit preservation coating can improve the quality of agricultural products, extend the shelf life of food, and reduce the cost of cold-chain transportation.

Pectin Edible Films Filled with Ilex paraguariensis Concentrate Extract and Its Characterization

Ilex paraguariensis (IP) extract was added to prepare edible films using a central rotational composite design (CCRD) 22 with IP extract and sorbitol concentrations as variables. The IP extract was characterized by color parameters, total phenolic content, caffeine, flavonoids, and chlorophyll content, and antioxidant activity and the edible films were assessed for the same analysis and thickness, water vapor permeability (WVP), solubility in water, fluorescence, photodegradation and UV/Vis light barrier, FT-IR, thermogravimetry, and differential exploratory colorimetry. Sorbitol increased thickness and WVP, while the extract influenced the concentration of phenolic compounds in the films. The optimum concentrations of extract and sorbitol were 10% and 15%, respectively. Films presented thermal resistance (until 230 °C) and an excellent barrier to UV light. Furthermore, these films could carry compounds originally in IP, showing good functional properties concerning the water vapor barrier (showing a great variation scale due to the possibility to increase sorbitol or not, between 3.33 and 5.27 g mm/m2 day KPa). The films showed great potential to replace conventional primary packaging, and if consumed with food, as a bullet paper, they can add nutritional value to the packaged product.

Production and characterization of biosurfactants from lactic acid bacteria in Dadiah for strawberries edible coating

Biosurfactants are amphiphilic components applied in various fields, one of which is preserving agricultural products. Biosurfactants can be used as additives in edible coatings to prevent microbial adhesion by reducing surface tension on the fruit surface. They also play a role in increasing the moisture barrier and slowing down the physiological changes of fruit. Nonetheless, biosurfactants were often produced by non-GRAS bacteria. GRAS biosurfactant-producing bacteria are urgently needed for application in food products. This study aims to isolate and characterize biosurfactant-producing strains of lactic acid bacteria from Dadiah and evaluate their efficacy in reducing microbial adhesion on strawberries. From four selected isolates found in Dadiah, Lactiplantibacillus plantarum was the best candidate, producing biosurfactant with index emulsification (EI24) of 64.48 ± 0.37% with a CMC of 1 g/l. LC-MS and FT-IR characterized the biosurfactants as glycolipids. The rate of antibacterial and anti-adhesive tests on Escherichia coli ATCC 8739 were 18.79 ± 5.23% and 55.26 ± 0.02%, while on Staphylococcus aureus ATCC 6738 were 31.60 ± 2.63% and 74.63 ± 0.00% at a concentration of 3000 mg/l. However, no anti-fungal activity against Rhizopus stolonifer and Aspergillus niger was observed at the same concentration. Compared to SDS, biosurfactants demonstrated non-toxicity with an LC50 value of 2.94 x 108 mg/l. A combination of 1% chitosan reduced the number of fungal cells by 29.76 ± 3.25% on 125 mg/l biosurfactant and bacterial cells by 31.91 ± 5.06% on 1000 mg/l biosurfactant after 10 days, indicating their potential to reduce fruit spoilage and enhance microbial anti-adhesive properties of edible coatings.

Chitosan nanoparticles and neem essential oil functionalized pullulan/gum arabic active edible biocomposites for fresh-cut guava preservation

The study demonstrates the preparation of active edible biocomposites using Pullulan (PUL) and Gum Arabic (GA), functionalized with Chitosan Nanoparticles (NCS) and Neem Essential Oil (NEO). These biocomposites addressed the issues of high hydrophilicity and poor barrier properties in packaging. The effects of varying NCS concentrations (1 %, 2 %, and 3 %) on various film properties were studied, while keeping PUL, GA, and NEO concentrations constant. The biocomposite containing NEO and 3 % NCS (PUL/GA/NCS3/NEO), significantly improved surface properties, transforming it from hydrophilic (water contact angle 55.49 ± 2.31°) to hydrophobic (115.01 ± 1.86°). Additionally, tensile strength increased by ∼12.77 MPa, elongation at break by ∼6.26 %, thermal stability (Toffset) by ∼22.49 °C, and water vapour barrier by ∼45.95 %, alongside enhanced UV-shielding, antimicrobial and antioxidant properties. The EDX analysis confirmed the biocomposite safety, with 55.7 % carbon (C), 3.6 % nitrogen (N), and 40.8 % oxygen (O). Moreover, in vitro biocompatibility tests on Human Embryonic Kidney (HEK-293) cells indicated non-cytotoxicity, with 86.82 ± 2.28 % viability after 72 h. Furthermore, the practical application of PUL/GA/NCS3/NEO solution was tested as an edible coating material for fresh-cut guava preservation. The coated guava better maintained storage quality parameters in terms of colour, weight loss, firmness, microbiological shelf-life and antioxidant activity, under both ambient and refrigerated conditions.

Chitosan Based Edible Coatings: Enhancing Shelf Life and Quality in Fruits and Vegetables

Chitosan-based edible coatings have gained considerable attention as a sustainable solution for harvested fruits and vegetables which are highly prone to post harvest decay and quality deterioration during storage. Chitosan, derived from chitin exhibits biocompatibility, biodegradability and antimicrobial properties making it an ideal material for edible coatings. Edible coating act as effective barriers to moisture loss, gas exchange and microbial contamination thereby enhancing the quality and extending the shelf life of produce. Research has shown that chitosan coatings can significantly reduce respiration rates, inhibit enzymatic browning and preserve the sensory qualities of fruits and vegetables, contributing to a reduction in food waste and improved food security. The effectiveness of chitosan based coating is influenced by factors such as chitosan concentration, the addition of other natural additives and the methods of application. Studies have demonstrated that chitosan coatings alone or in combination with essential oils or plant extracts effectively reduce weight loss, maintain firmness and prevent spoilage in horticultural perishables. Additionally, nano-encapsulated chitosan formulations have been explored for their enhanced protective effects offering more uniform coatings with superior barrier properties. The application of chitosan coatings is expected to evolve with the integration of nanotechnology, the development of functionalized chitosan molecules and the use of biocompatible additives. Chitosan coatings have been successfully applied commercially, such as in the preservation of perishables illustrating their potential as a sustainable solution with practical benefits for both scientific advancement and industrial application These innovations will further improve the efficacy of coatings by enhancing their moisture and gas barrier properties along with antimicrobial and antioxidant properties. Additionally, sustainability concerns are driving research into eco-friendly sources of edible coating and chitosan is a promising alternative to synthetic or chemical ingredients or fungicides. As the technology advances, chitosan based edible coatings are likely to have increased commercial adoption due to its sustainable and biodegradable nature. However, Chitosan-based coatings face challenges with solubility, application consistency, scalability, cost, allergen concerns, and varying regulatory standards.

Furan-based renewable elastomers as effective tougheners for PLA: Enhanced mechanical properties and water vapor barrier properties

There is a great need for versatile biomass additives sourced from renewable materials to enhance the performance of polylactic acid (PLA) composites. This study introduces a furan-based polyester elastomer called PNF-PBC that is designed to improve the mechanical and water vapor barrier characteristics of PLA. By incorporating PNF-PBC into PLA, the toughness of the PLA/PNF-PBC biocomposites was considerably enhanced through various intermolecular interactions. A 15 wt% PNF-PBC blend with PLA exhibited a 13.6-fold increase in elongation at break, while having a negligible impact on tensile strength. Furthermore, the water vapor barrier performance of PLA/PNF-PBC biocomposites was greatly boosted by a factor of 10 compared to pure PLA, making them highly suitable for food packaging materials. With its versatile properties, we anticipate that this bio-based PLA/PNF-PBC material will significantly expand the range of applications for PLA composites.

Multi-functional polysaccharides composite film containing cashew and jik leaf carbon dots: Properties and bioactivities

Carbon dots (CDs) from the leaf powders of cashew (C-CDs), jik (J-CDs) and the mixed cashew/jik (1:1) (CJ-CDs) using hydrothermal method were synthesized and characterized. All three CDs were incorporated into chitosan/starch composite (CS) film at the level of 3 % (w/w). Microstructure images revealed that all films had slight differences in surface and internal structure. Thickness of the CS film increased with the inclusion of fillers (CDs). Inclusion of CDs slightly reduced the tensile and water vapor barrier properties of the CS film. CS film containing C-CDs exhibited the improved elasticity, UV barrier and antioxidant activity among all the films tested. Color and opaqueness of the resulting films were governed by the yellowish CDs. Distinctive peaks of resulting CS film were detected in FTIR spectra, while all CDs had no marked effect on the spectra. The release of CDs from films was more pronounced in water than in alcoholic solutions (10–95 % ethanol). Strongest antibacterial activities against Listeria monocytogenes and Escherichia coli were recorded for CDs added film, in which the highest activities were found for CS/CJ-CDs film. Thermal stability was also enhanced in CS/CJ-CDs film. Thus, the CS film loaded with CDs, especially from the mixture of cashew and jik leaf powders could serve as a promising active packaging for inactivation of some pathogens in food products.

Troxerutin associated with Agaricus blazei Murill polysaccharides in films improves full-thickness wound healing

The present study aimed to associate troxerutin (TRX) with polysaccharides from Agaricus blazei Murill mushroom (PolyAb) in alginate/PVA films and evaluate their effect on wound healing. The physicochemical, mechanical, morphological, and water vapor barrier properties of the films were studied, and their biological potential was analyzed in vivo using the full-thickness wound healing model. The association between TRX and PolyAb present in the polymeric film contributed to increased thermal stability, mechanical resistance, and elasticity when compared to films without TRX, which indicated good miscibility of the excipients. In the in vivo tests, the TRX films promoted greater collagen deposition and repair of epidermis and dermis layers. The 0.25 % TRX film showed an increase in reduced glutathione levels, while the 1.0 % TRX film reduced lipid peroxidation and production of the pro-inflammatory cytokine IL-1β, demonstrating the anti-inflammatory and antioxidant effect of TRX films. Therefore, it is estimated that the film containing 1 % TRX can be used as biocurative for wound dressing applications.

A Fluorescent Polyvinyl Alcohol Film with Efficient Photodynamic Antimicrobial Performance Enabled by Berberine/Phytic Acid Salt for Food Preservation

AbstractFood packaging that impedes microbial growth and can be safely used is critical to attenuate food spoilage. Herein, a green berberine/phytate salt (BPA) is successfully synthesized and aggregated in polyvinyl alcohol (PVA) film to impart fluorescent and photodynamic antimicrobial properties. Compared to berberine hydrochloride (BHL), BPA exhibited stronger fluorescence because intramolecular motions and intermolecular π–π accumulation of BHL are restricted by phytic acid (PA). Molecular dynamics simulation indicate that aggregation of BHL and PA formed through electrostatic interactions in the PVA matrix due to the change of the binding energy during the drying process. With increasing BPA content, the films exhibited increased ultraviolet, water vapor, and oxygen barriers and fluorescent properties, but reduced tensile strength and elongation at break. After radiated, PVA‐BPA9 film showed the highest antimicrobial rates against Staphylococcus aureus, Escherichia coli, P. citrinum, and Aspergillus niger reached 100%, 100%, 86.14%, and 66.24%, respectively, due to the increased reactive oxygen species production. The total number of microbial colonies in cooked chicken and oranges packaged by PVA‐BPA9 film with irradiation ARE 87.54% and 29.21% of those by PVA film. The findings indicate a new and feasible strategy to obtain a green photodynamic‐mediated film for safe and effective food packaging.

Aluminate-activated nano-SiO2 for enhancing water vapor barrier properties in polymers films: A safe and effective strategy

In this work, a series of nanocomposite films composed of polylactic acid (PLA), poly (butylene adipate-co-terephthalate) (PBAT), polybutylene succinate (PBS), nano-SiO2 activated by aluminate for different times were developed to enhance water vapor barrier properties. The physiochemical and thermal properties of the films were characterized. In addition, total and aluminum migration from the films was monitored, and non-targeted screening was performed to evaluate the potential safety of the composite films. Fourier Transform infrared spectroscopy analysis indicated that the nano-SiO2 was successfully activated by aluminate. Differential scanning calorimetry analysis indicated that incorporation of the activated nano-SiO2 slightly reduced the glass transition temperature (from 54 to 51 °C) and increased the crystallinity degree (from 6.9 % to 11.1 %) of PLA. Incorporation of 0.4 % nanofillers was found to give the highest crystallinity. Thermogravimetric analysis showed that the thermal stability of the PLA/PBAT/PBS films did not change significantly after adding the activated-nano-SiO2. However, the incorporation of these nanofillers did increase the interfacial roughness and crystallinity degree of the films, thereby reducing the water vapor permeability by around 30 %. Erucamide was detected in the composite films after exposure to food simulants, however, the films containing the nanofillers still met European Union safety standards. In summary, the nanofiller-loaded polymer films developed in this study were shown to be safe and have high water barrier properties, which means they may be suitable for application in the food, cosmetic, personal care, pharmaceutical, and agrochemical industries.

Development of polycaprolactone-based electrospun nanofiber incorporated lemon beebrush essential oil-loaded metal-organic frameworks as a novel active food packaging for meat preservation

This research involved the development of novel antimicrobial and antioxidant food packaging using electrospun nanofibrous films (ENFs) made of polycaprolactone (PCL) with added lemon beebrush (Aloysia Citriodora) essential oil (LEO)–loaded chromium(III)-metal–organic framework (Cr(III)-MOF) to extend the shelf life of red meat. We conducted a comprehensive range of microstructure, physical, and mechanical tests on nanofibers based on PCL. The PCL/LEO@Cr(III)-MOF nanofibers displayed improved thermal stability, anti-deformation capacity, and increased TS (62.3–68.2 MPa) but reduced flexibility (32.6–28.2 %). Moreover, the inclusion of LEO@Cr(III)-MOF led to a decreased hydrophobic surface due to the formation of hydrogen bonds, as well as a reduction in the water vapor barrier (2.8–2.2 × 10−11 g m/m2. s. Pa). Additionally, the PCL/LEO@Cr(III)-MOF nanofibers exhibited antibacterial (E. coli (20.3 mm) and S. aureus (24.3 mm)) and antioxidant (DPPH and ABTS) activity. The effectiveness of PCL-based nanofibers was evaluated in red meat samples stored at a temperature of 4 °C, and the findings demonstrated that PCL/LEO@Cr(III)-MOF nanofibers preserved the chemical (pH, TVB-N, PV, and TBA) and microbial quality (PTC and TVC) of the samples and prolonged their shelf life by 18 days. These findings indicate the promising potential of the developed PCL/LEO@Cr(III)-MOF electrospun nanofibers for active food packaging.

Liposome/chitosan coating film bioplastic packaging for Litchi fruit preservation

Chitosan is an ideal coating film for food preservation, but the performance of a single chitosan coating film is not good. Herein, the liposome was prepared by embedding copper nanoparticles (CuNPs) and thyme essential oil (TEO) in the hydrophilic and hydrophobic double-domain structure formed by phospholipids, and combining with chitosan to obtain a chitosan-based coating film for litchi preservation. The liposome was well-dispersed and stable with an average particle size of about 190 nm. The liposome showed excellent controllable release properties, and the cumulative release rate of TEO was 65.17 % and that of CuNPs was 15.17 % after 7 days. Furthermore, the oxygen and water vapor barrier properties of the coating film were greatly improved. Importantly, the film possessed effective antioxidant, antibacterial activity and excellent safety, which presents a better fresh-keeping effect on litchi. This study provides insights into the design and manufacture of food packaging for controllable and long-lasting preservation.

Properties of Antioxidant Film Based on Protein Isolate and Seed Coat Extract from Bambara Groundnut.

Bambara groundnut (BG)-based films containing seed coat extract at different concentrations were prepared and characterized. BG seed coat extract (BGSCE) had a total phenolic content of 708.38 mg GAE/g dry extract. BGSCE majorly consisted of quercetin 3-galactoside, rutin, and azaleatin 3-arabinoside. BGSCE exhibited ABTS and DPPH radical scavenging activities (ABTS-RSAs and DPPH-RSAs), a ferric reducing antioxidant power (FRAP), and an oxygen radical absorbance capacity (ORAC) of 66.44, 4.98, 4.42, and 0.91 mmol Trolox equivalent/g dry extract, respectively. When BGSCE at various concentrations (0-8%, w/w, protein content) was incorporated into the BG protein isolate (BG-PI)-based films, film containing 4% BGSCE exhibited higher thickness, tensile strength, elongation at break, water vapor and UV-light barrier properties, and a*-value (redness) than the control film (p < 0.05). Films containing BGSCE had greater ABTS-RSA, FRAP, and ORAC than the control film (p < 0.05). An FTIR analysis elucidated that the proteins interacted with phenolic compounds in BGSCE. Nonetheless, less thermal stability was attained in films added with BGSCE. Hence, the addition of BGSCE possessing antioxidant activity exhibited an important role in properties and characteristics of BG-PI-based film. The developed active film could be applied as packaging material possessing antioxidant property for food applications.

Effect of surface charge on mechano-bactericidal activity of cellulose nanocrystals constructed chevaux-de-frise and meat preservation

The nanostructured insect wings have inspired the development of antimicrobial surfaces with mechano-bactericidal activity. For the first time, a chevaux-de-frise-like nanostructure was fabricated through the coating of cellulose nanocrystals (CNC) onto regenerated cellulose (RC) films via vacuum filtration and the impact of contact time, temperature, and surface topography on eliminating foodborne bacteria was examined. Herein, our focus is to explore in more detail how the surface charge of CNC affects the mechano-bactericidal activity and the performance of chevaux-de-frise-like nanostructure in meat preservation. CNC with neutral (weak), negative, and positive charges were prepared by hydrochloric acid hydrolysis (HCNC), TEMPO oxidation (TCNC), and amination (ACNC), respectively, and showed similar reinforcing effects on the tensile strength (increased from 74.23 ± 1.20 to about 100 MPa) and water vapor barrier property (reduced from 1.83 ± 0.08 to about 1.20 × 10−7 g m−1 h−1 Pa−1). Among them, RC-ACNC showed the highest log reduction against Escherichia coli (0.83 ± 0.06) and Staphylococcus aureus (0.69 ± 0.04) after 5 min contact, respectively, indicating the important role of attractive force in fast eliminating bacteria upon contact. It was worth noting that, during the meat preservation test, all three CNC-coated RC films exhibited a similar 0.4 log reduction of bacteria after day 4, likely due to the same physical attachment with an extended contact time. Therefore, the construction of chevaux-de-frise nanostructure from CNC on food packaging provides a sustainable strategy to contribute to preventing bacterial growth.

Visible-light-driven Fe-catalyzed alkylation for synthesizing functionalized polyolefin elastomers as advanced encapsulants in photovoltaic modules

Polyolefin elastomer (POE) has emerged as a promising encapsulant for photovoltaic modules, attributed to its exceptional water vapor barrier properties, robust weather resistance, and enhanced anti-potential induced degradation (anti-PID) capabilities. Despite these advantages, the interfacial adhesion of POE remains a significant challenge, particularly its suboptimal bonding with glass and solar cells, which impedes its broader application within the photovoltaic industry. This study introduced glycidyl methacrylate (GMA) monomers into POE through a photo-induced iron-catalyzed alkylation reaction, developing a novel polyolefin encapsulant for photovoltaic modules. The encapsulant was designed to possess high light transmittance, enhanced adhesion, and elevated resistivity. The modified POE boasts an impressive light transmittance nearing 98% and an adhesive strength of 28.3 N cm−1, both superior to traditional ethylene-vinyl acetate copolymer (EVA) materials. Additionally, this work delves into the correlation between crystallization behavior and light transmittance, elucidating the influence of GMA incorporation on the adhesion and insulation properties of POE through gaussian simulations.

Envelope Deficiencies and Thermo-Hygrometric Challenges in Warehouse-Type Buildings in Subtropical Climates: A Case Study of a Nori Distribution Center

Enhancing the energy efficiency and climate resilience of existing buildings is crucial amid growing environmental challenges. While extensive research has focused on non-residential buildings, studies on thermo-hygrometric conditions in warehouse-type buildings, particularly in subtropical climates, remain limited. This study investigated the impact of building envelope deficiencies on indoor thermal and moisture regulation at the Nori Distribution Center. Using infrared thermal imaging and long-term environmental monitoring, significant thermo-hygrometric fluctuations were identified, primarily due to design and construction deficiencies. Poor insulation, inadequate sealing, and the lack of moisture barriers contributed to unstable indoor temperature and humidity. Seasonal analysis showed that during summer, the median second-floor air temperature reached 28.8 °C, peaking at 39.2 °C, with relative humidity exceeding 70% for 45% of the time. First-floor relative humidity surpassed 70% for 72% of the time. While condensation risk remains low year-round, it increases significantly with air infiltration through gaps in the building envelope. This study recommends enhancing the sealing of the building envelope, upgrading insulation materials and moisture barriers, particularly in the roof, and optimizing the HVAC system to improve energy efficiency and storage conditions. These findings offer valuable recommendations for retrofitting warehouse-type buildings in subtropical climates to improve energy efficiency and climate resilience.

Improving Hydrophobicity and Water Vapor Barrier Properties in Paper Using Cellulose Nanofiber-Stabilized Cocoa Butter and PLA Emulsions

This study explores the use of cellulose nanofiber (CNF)-stabilized Pickering emulsions for paper coatings, focusing on their rheological properties and effects on hydrophilicity and water vapor transmission rate (WVTR). Two types of Pickering emulsions, oil-in-water (O/W), were stabilized with 1 wt% CNF extracted from fique by-products. The oily phases of the emulsions were composed of poly(lactic acid) (PLA) and cocoa butter (CB). The physical stability, viscosity, and viscoelasticity of the emulsions were characterized. The emulsions were applied to the surfaces of Bond and Kraft papers using the rod-coating method. The coating process involved first applying a layer of the PLA emulsion followed by a layer of the CB emulsion. The coated papers were then evaluated by FE-SEM, contact angle, adhesion work, and water vapor transmission rate (WVTR). The results indicated that the coatings effectively produced a slightly hydrophobic surface on the papers, with contact angles approaching 90°. Initially, Kraft paper exhibited a WVTR value of 29.20 ± 1.13 g/m2·h, which significantly decreased to 7.06 ± 2.80 g/m2·h after coating, representing a reduction of 75.82%. Similarly, natural Bond paper showed a WVTR value of 30.56 ± 0.34 g/m2·h, which decreased to 14.37 ± 5.91 g/m2·h after coating, indicating a reduction of 47.02%. These findings demonstrate the potential of CNF-stabilized Pickering emulsions for enhancing the performance of paper coatings in terms of hydrophobicity and moisture barrier properties. The approach of this study aligns with global sustainability goals in packaging materials combining the use of PLA and CB to develop a waterborne coating to enhance the moisture barrier properties, demonstrated by a substantial reduction in water vapor transmission rates, and an improved hydrophobicity of coated papers.

Toward mechanical recyclability of high barrier food packaging films through filler incorporation on the EVOH layer

AbstractTo preserve food from moisture and oxygen, polymers, such as ethylene vinyl alcohol (EVOH) are used in multilayer structures to provide oxygen barrier, while low‐density polyethylene (LDPE) is used for a water vapor barrier. While this material combination is functionally ideal, it may not comply with the new packaging recycling guidelines. Some European markets have implemented rules that limit the weight percentage of EVOH in LDPE films. One way to increase recyclability is by reducing the amount of EVOH in the film structure while maintaining the packaging's oxygen barrier properties. To achieve this, it is necessary to improve the barrier properties of EVOH. With this objective in mind, this study evaluated the incorporation of nanoclays (NC), cellulose microcrystals (MCC), silicon dioxide nanoparticles (SiO2), and cellulose nanocrystals (CNC) into an EVOH matrix. The results indicate that NC and MCC facilitate a stable blown film extrusion process and have a better dispersion in the EVOH matrix. Based on this finding, three‐layer films (with an ABA configuration) consisting of LDPE (A) and EVOH (7 μm layer) with 0.5 or 1 wt.% MCC or NC (B) were produced to protect the EVOH from moisture and enable blown film processing. The oxygen transmission rate (OTR) values were lowest for 0.5 wt.% NC and 1 wt.% MCC incorporation. Although the films with micro and nanoparticles had increased haze, this did not affect the visibility of the packaged food.

Preparation of pectin/carboxymethyl cellulose composite films via high-pressure processing and enhancement of antimicrobial packaging

This study investigated the impact of high-pressure processing (HPP) treatment on the structure and physicochemical properties of pectin (PEC)/carboxymethyl cellulose (CMC) composite films, along with the development of new active films incorporating emodin as an antibacterial agent. The results showed that 500 MPa/20 min HPP treatment significantly improved the tensile strength (from 45.91 ± 4.63 MPa to 52.24 ± 4.87 MPa) and elongation at the break (from 5.00 ± 1.44 % to 11.72 ± 2.97 %) of the films. It also improved the film's thermal stability and had no significant effect on its thermal degradability. Moreover, emodin was incorporated into the PEC/CMC film-forming solution and subjected to 500 MPa/20 min HPP treatment to investigate the structure, functional properties, optical properties, and antibacterial activity of the film. The emodin caused the film structural alteration, but significantly improved the water vapor barrier properties. It also reduced the film brightness and light transmission. The antibacterial assessment demonstrated that the film's antibacterial activity was correlated positively with increasing emodin content, and the number of viable cells of Staphylococcus aureus decreased by 1.29 log10 CFU/mL, 1.70 log10 CFU/mL, and 1.80 log10 CFU/mL with different levels of EM antimicrobial films after 12 h.