Water Vapor Permeability Research Articles

Fabrication of CuO nanoparticles embedded novel chitosan/hydroxypropyl cellulose bio-nanocomposites for active packaging of jamun fruit

The study herein was intended to develop CuO nanoparticles (CuO NPs) embedded in chitosan (CS) and hydroxypropyl cellulose (HPC) based bio-nanocomposites with improved functional properties to prolong the shelf life of fruits using eco-friendly solvent casting technique. ATR-FTIR spectroscopy revealed hydrogen bonding interactions between the CS, HPC and CuO NPs. The homogeneity of the CuO NPs distributed bio-nanocomposites was verified by SEM images with minimum aggregations. Bio-nanocomposites showed improved mechanical properties (tensile strength of 33 MPa) with excellent UV-light blocking ability (4% of %transmittance at 360 nm and 20% transparency at 600 nm), also, a significant decrease in moisture adsorption (5.27%), water vapour permeability (2.47%), oxygen permeability (1.39%), and biodegradability (12.58%) compared to control CS/HPC blend film. Furthermore, CuO NPs induced CS/HPC bio-nanocomposites exhibited strong antimicrobial properties against B. subtilis, S. aureus, P. aeruginosa, E. coli, and C. albicans as well as antioxidant properties. Moreover, 0.8% of CuO NPs embedded in CS/HPC bio-nanocomposite film extended the shelf life of packed jamun fruits confirming the potential of prepared bio-nanocomposites to serve as an active food packaging material.

A novel multifunctional carboxymethyl cellulose packaging film with encapsulated lemon oil for quality enhancement of cherry tomato and baby spinach leaves

This is the first report on fabricating an active edible film based on CMC and lemon essential oil (LEO) micro/nanocapsules for packaging cherry tomatoes and baby spinach leaves. LEO extracted by hydrodistillation from lemon peels was efficiently encapsulated by oil-in-water emulsification method using high dextrose equivalent maltodextrin (MD) as the sole wall material, yielding physically stable MD-LEO micro/nanocapsules with potent cytotoxicity against Caco-2 cells, and antimicrobial activity against foodborne pathogens. Incorporating LEO micro/nanocapsules into CMC confirmed by SEM/FTIR analyses, significantly improved the film's water vapor permeability by 37.50%, increased its thermal stability by 25 ℃, and reduced its moisture content/water absorption. The transparent film demonstrated strong DPPH radicle scavenging activity, UV-blocking ability, low moisture, enhanced tensile strength, and soil biodegradability (96.84%) within 14 days. Direct application of the novel film as a single-layer overwrap to cherry tomatoes and spinach leaves stored at abusive temperature for up to 4 days revealed good prospects of preserving physical appearance, preventing water/texture loss, maintaining pH, and inhibiting growth of aerobic mesophilic/E. coli O157:H7 populations by 0.65 and 1.0 log units, respectively, highlighting that CMC is an optimal vehicle for encapsulated LEO. The data emphasizes the significant contribution of the novel film to active packaging of minimally processed fresh produce and its potential to compete with inert plastic films dominating food markets. Extending the film's applicability range to other pertinent food systems may promote industrial interest for production upscaling as a commercially viable postharvest preservation strategy to meet the demands of sustainable packaging industry in Egypt.

Study of coating effectiveness of grape fruit seed extract incorporated Chitosan/cornstarch based active packaging film on grapes

The aim of the present study was to optimize the manufacturing process of grapefruit seed extract (GFSE) incorporated Chitosan (0.75 %, 2 % w/w) and various corn starch concentration of CHCS film of ratio 2:1, 1:1, 1:2 respectively using sorbitol as plasticizer. Optimization of chitosan concentration in chitosan corn starch film was done on the basis of physicochemical properties e.g. moisture content, film thickness, solubility, water vapour permeability and characterization of the films were done. It was reported that the films with CH: CS ratio 2:1 had tensile strength values comparable to that of other films with CH: CS ratio 1:1 and 1:2. Hence, films with 2 % (w/w) chitosan and CH: CS ratio 2:1 was found best among all the film samples shelf life extended to 20 days. GFSE incorporated film was found to have better anti-microbial properties as compared to commercial polypropylene (PP) and low density polyethylene (LDPE) films. GFSE incorporated CHCS film of ratio 2:1 was applied on Grape fruits. The antimicrobial effect of coating formulation on grape was mathematically calculated by predictive kinetic models and digital imaging. Sensory evaluation of applied coating formulation was found very efficient and confirmed the shelf life enhancement of 20 days.

Characterization of biodegradable bi‐layer films from thermoplastic starch and poly‐l‐lactic acid

AbstractThis study aimed to enhance the oxygen barrier properties of polylactic acid (PLA) film, a biodegradable packaging material with high oxygen permeability (OP). Bi‐layer films were produced by coating thermoplastic starch (TPS) onto PLA films in various ratios while maintaining constant film thickness. The mechanical, optical, barrier, thermal, hydrophobicity, moisture sorption, and microstructural properties of the films were analyzed. Increasing the TPS ratio elevated moisture content (MC), water uptake, solubility, and opacity while enhancing UV barrier properties. TPS coating reduced tensile and burst strength but increased the burst deformation of the bi‐layer films. Bi‐layer film production resulted in a water vapor permeability increase of 59.26%–94.44% compared with neat PLA while decreasing OP by 2.52%–29.66%. The equilibrium moisture content (EMC) rose with higher TPS ratios, displaying type II isotherms. FTIR analysis indicated no chemical interactions between PLA and TPS. Increasing the TPS ratio decreased PLA crystallinity, supporting the mechanical and barrier properties of the bi‐layer films. Neat and bi‐layer films exhibited smooth, homogeneous surfaces, with a visible interface in the cross‐section of the bi‐layer films. In conclusion, TPS shows promise as an alternative to improve oxygen barrier properties in PLA films without adversely affecting other properties.

Characterization of Sodium Alginate‐Based Edible Active Coating Incorporated with Dendrobium officinale Polysaccharides and Its Application in Grape Packaging

AbstractIn the present study, Dendrobium officinale polysaccharides (DOPs) are incorporated into sodium alginate (SA) for the development of SA‐DOPs films. The physical, mechanical, and functional properties of SA‐DOPs composite films and their ability to preserve fresh grapes are investigated. The results reveal that the addition of DOPs can significantly enhance the thickness, swelling ratio, tensile strength, elongation at break, and thermal stability of the films (p < 0.05) whereas the water solubility and water vapor permeability are decreased. Fourier transform‐infrared (FT‐IR) spectroscopy results reflect interaction of chemical groups and bonds between SA and DOPs. The result of scanning of electron microscopy (SEM) indicates smooth for SA‐DOPs films while control film exhibits rough. The SA‐DOPs films exhibit potential antioxidant effects on 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) and 2,2'‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS) free radicals. Furthermore, the composite films exhibit remarkable inhibition of the growth of Escherichia coli and Staphylococcus aureus (p < 0.05). In addition, the SA‐DOPs coatings can effectively reduce weight loss, inhibit polyphenol oxidase activity, extend the shelf life of the grapes at room temperature (25 ± 1 °C) for 14 days. These results indicate that the SA‐DOPs edible coatings might be a promising candidate in food preservation industries.

A Colorimetric Nanofiber Film Based on Ethyl Cellulose/Gelatin/Purple Sweet Potato Anthocyanins for Monitoring Pork Freshness.

In this study, colorimetric indicator nanofiber films based on ethyl cellulose (EC)/gelatin (G) incorporating purple sweet potato anthocyanins (PSPAs) were designed via electrospinning technology for monitoring and maintaining the freshness of pork. The film presented good structural integrity and stability in a humid environment with water vapor permeability (WVP) of 6.07 ± 0.14 × 10-11 g·m-1s-1Pa-1 and water contact angle (WCA) of 81.62 ± 1.43°. When PSPAs were added into the nanofiber films, the antioxidant capacity was significantly improved (p < 0.05) with a DPPH radical scavenging rate of 68.61 ± 1.80%. The nanofiber films showed distinguishable color changes as pH changes and was highly sensitive to volatile ammonia than that of casting films. In the application test, the film color changed from light pink (fresh stage) to light brown (secondary freshness stage) and then to brownish green (spoilage stage), indicating that the nanofiber films can be used to detect the real-time freshness of pork during storage. Meanwhile, it could prolong the shelf life of pork by inhibiting the oxidation degree. Hence, these results suggested that the EC/G/PSPA film has promising future for monitoring freshness and extending shelf life of pork.

Preparation of pullulan-shellac edible films with improved water-resistance and UV barrier properties for Chinese cherries preservation

In order to improve the water-resistance and ultraviolet (UV) barrier properties of pullulan (PL) film, edible composite films were prepared by solution casting based on PL and shellac (SH). The physical properties, thermal stability, mechanical properties, water vapor permeability and UV barrier of the composite films were characterized. The analysis of the functional properties revealed that the composite films had good compatibility, water-resistance (33.50˚–60.15˚), and strong UV-blocking properties (84.60%–0.00%). The addition of SH improved the water-resistance and mechanical properties of the films, but the thermal stability was slightly reduced. These films can be used as an edible coating on Chinese cherries. According to the characteristics of weight loss, decay incidence and other indicators of cherries, the PL-SH composite films can keep Chinese cherries fresh at room temperature at least for 7 days. Therefore, PL-SH composite films may be an environmentally friendly packaging material with application prospects in the fruit preservation industry.

Polyethylene terephthalate bottles with excellent oxygen, water vapor barrier and mechanical performances prepared by injection and blow molding

AbstractIn this work, the oxygen barrier property of polyethylene terephthalate (PET) films was enhanced by optimizing the “active” and “passive” synergistic barrier approaches, that is, integration of high barrier material polyethylene naphthalate (PEN) and oxygen scavengers along with catalyst with PET before biaxially stretching the PET blended films. When the PEN content in the PET blended films reached 50 wt%, the oxygen permeability coefficient was significantly reduced to 0.9687 cc·mil·m−2·day−1·0.1 MPa−1, showing an enhancement of 117.4 times compared to the pure PET film. Furthermore, the water vapor permeability coefficient was reduced to 8.0208 g·mil·m−2·day−1, representing a 45.5% reduction in comparison to the pristine PET film. It also maintained a higher transverse and longitudinal tensile strength (110.5 and 127.2 MPa) than PET film only with oxygen scavengers and catalyst (53.5 and 78.0 MPa). This work presents a viable and practical approach to endow PET materials with simultaneously enhanced oxygen, water barrier performance, and mechanical property.Highlights The OPC of PET film was as low as 0.9687 cc·mil·m−2·day−1·0.1 MPa−1. The “active” and “passive” barrier techniques together reduced the OPC of PET film.

Electrically conductive bioplastics based on chitosan, polyvinyl alcohol, polyvinyl pyrrolidone, and plant extract nanoparticles for detecting Rhizopus stolonifer on tomato fruit

AbstractThis work aimed to manufacture bioplastics with mechanical and electrical properties for monitoring the Rhizopus stolonifer growth in tomato fruit packaging. Bioplastics were based on chitosan/polyvinyl alcohol (Ch/PVA), chitosan/polyvinyl pyrrolidone (Ch/PVP), and nanoparticles (NPs) of plant extracts at 10% and 30% of concentrations. Bioplastics were exposed to tomato inoculated with R. stolonifer for 6 d at 25°C. Water vapor permeability (WVP), mechanical properties, FTIR, UV–vis, morphology, electrical resistance of bioplastics, and the NPs size were assessed. In bioplastics added with plant extracts, 1.5 times more WVP than in the control group (18–35 gs−1m−1Pa−1) were quantified. Ch/PVA bioplastic showed 51% more tensile strength, 44% more elongation at break, and 40% more Young's modulus than Ch/PVP, regardless of the plant extract. The electrical resistance in Ch/PVA bioplastics with 30% mushroom extract and 10% radish allowed the differentiation between inoculated (109–1010 Ω) and non‐inoculated tomatoes (1010–1011 Ω). The FTIR assay confirmed the presence of each compound used in the bioplastic, and UV–vis confirmed phenols at 300 nm. The NPs measured less than 50 nm. Only Ch/PVA with 30% mushroom and 10% radish can be useful to monitor fungi in tomatoes based on their electrical behavior.

Water vapour permeability of inorganic construction materials

Water vapour permeability (WVP) data on brick, stone, plaster and cement-based materials from some seventy publications are reviewed and assessed. Almost all sources use standard cup-test methods or close variants. Comparisons of WVP values from different sources on similar materials confirm that reproducibility between different laboratories is poor. Some deficiencies of cup-test methods are discussed, including uncertainties arising from the use of saturated-salt humidistats and desiccants. There is evidence that the water vapour resistance factor decreases as volume-fraction porosity increases, and data support a simple porosity–tortuosity relation. Data also show that the resistance factor decreases with increasing mean relative humidity across the test specimen, with the wet-cup value consistently lower than the dry-cup values for a given material. The contribution of liquid film flow to mass transfer is discussed. It is shown how film thickness and film-flow permeability may be estimated from the water-vapour sorption isotherm; and a related regression equation is developed It is concluded that available data are inadequate to establish the fundamental physics of WVP; vapour-only permeability data for engineering purposes should be obtained in dry-cup tests at low humidity; and research studies should aim to integrate the WVP into the framework of unsaturated flow theory.

Valorization of guinea grass seed (Megathyrsus maximus): Synthesis and utilization of cellulose microfiber to reinforce esterified and cross-linked guinea starch films

The present study extracts starch from guinea grass seed and fiber from the starch extraction residue. The fibrous residue was chemically converted into cellulose microfiber (CMF) and used to reinforce the native, esterified and crosslinked guinea starch films. The films were developed with 5 % starch, 40 % glycerol and 0, 2.5, 5, and 10 % CMF based on the dry matter of starch. SEM images of all film samples showed good compatibility of CMF with starch molecules, and no fractures or pores were observed. Adding filler materials to modified starch films slightly increased the film thickness (0.24 to 0.30 mm) due to the high dimensions of CMF, which comprise a significant amount of the composite's volume. A synergetic effect of starch modification and CMF in films decreased the moisture content (21.98 to 9.21 %), water solubility (25.65 to 15.47 %), water vapor permeability (6.96×10−7 to 1.65×10−7g∙mm2∙day∙Pa), and elongation at the break (33.51 to 16.79 %) while increasing the tensile strength (1.84 to 3.85 MPa) and Young's modulus (5.49 to 22.93 MPa). The L* and a* values of the films decreased, and the b* and opacity values of the films increased with the addition of CMF. The XRD graph showed that all films have semicrystalline structures with peaks at 18°, 20°, and 22°, and the degree of crystallinity increases (32.3 to 55.1 %) with CMF. All film samples showed good thermal stability up to 315 °C. In conclusion, esterified starch-based films exhibited superior barrier properties and flexibility. On the contrary, cross-linked starch films demonstrated higher tensile strength and lower water solubility.

Preparation and Characterization of Electrospun EVOH/Ti3C2 Composite Fibers.

In this work, the EVOH/Ti3C2 composite fibers were prepared via electrospinning and the effect of added Ti3C2 on the structure and properties of electrospun EVOH fibrous membranes was further investigated. The morphology, crystal structure, thermal properties, wettability, tensile properties, as well as air permeability and water vapor permeability of as-prepared EVOH/Ti3C2 composite fibers were studied. The Ti3C2 is uniformly loaded onto the surface and inside the composite fiber and affects the fiber diameters. Furthermore, The Ti3C2 self-orients along the fiber axis and does not change the crystal structure of the electrospun EVOH fibers, improving the crystallinity and thermal stability of the electrospun EVOH/Ti3C2 fibrous membranes. With the increase in the Ti3C2 concentration in the electrospinning polymer solution, the addition of Ti3C2 not only rapidly improves the wettability of the fibrous membranes, but also enhances their air permeability, compared with the pristine electrospun EVOH fibrous membranes. The experimental results provide theoretical guidance for the preparation of Ti3C2 composite fibers, and also expand the application of electrospun EVOH and EVOH/Ti3C2 fibrous membranes.

Preparation and characterization of biodegradable food packaging films using lemon peel pectin and chitosan incorporated with neem leaf extract and its application on apricot fruit

The present study aims to develop and characterize biodegradable packaging films from lemon peel-derived pectin and chitosan incorporated with a bioactive extract from neem leaves. The films (PCNE) contained varying concentrations of neem leaf extract and were comprehensively assessed for their physical, optical, mechanical, and antimicrobial attributes. The thickness, moisture content, water solubility, and water vapor permeability of the biodegradable packaging films increased with the increasing concentration of neem leaf extract. Comparatively, the tensile strength of the films decreased by 42.05 % compared to the control film. The Scanning Electron Microscopy (SEM) confirmed that the resultant blended pectin-chitosan films showed a uniform structure without cracks. Furthermore, the analysis targeting Staphylococcus aureus and Aspergillus niger indicated that the films had potent antimicrobial activity. Based on these results, the optimum films were selected and subsequently applied on apricot fruits to increase their shelf life at ambient temperature. The findings, after examining factors such as colour, firmness, total soluble solids, shrinkage, weight loss, and appearance, concluded that the apricots coated by PCNE-5 had the most delayed signs of spoilage and increased their shelf life by 50 %. The results showed the potential applicability of lemon peel pectin-chitosan-neem leaf extract blend films in biodegradable food packaging.

High-conductivity and long-term stability strain sensor based on silk fibroin and polyvinyl alcohol hydrogels

Conductive hydrogels as promising candidates of wearable electronic have attracted considerable interest in health monitoring, multifunctional electronic skins, and human-machine interfaces. However, to simultaneously achieve excellent electrical properties, long-term stability, and water vapor permeability of conductive hydrogels remains a challenge. Herein, a highly conductive hydrogel (MPRS) with high breathability (5.90 mg∙cm−2∙h−1), excellent electrical conductivity (6.67 S/m), high elongation (315%), and remarkable water retention properties was prepared adopting cold freeze-thawing method. MXene, poly (3, 4-ethylenedioxythiophene): poly (styrenesulfonate) (PEDOT: PSS), and reduced graphene oxide were used as conductive materials, while silk fibroin (SF) and polyvinyl alcohol (PVA) were used as the gel matrix. Lithium chloride solution was used as a solvent during the preparation process. The strain sensor based on this hydrogel demonstrates rapid response (0.33 s) and recovery ability (0.31 s) to strain stimuli. Upon 250 cycles of stretching at 35% strain, the output signal remains stable and highly repeatable, ensuring accurate detection of human joint movements and facial expressions. The fabrication of flexible electrodes using the hydrogel enabled real-time monitoring of human electromyography and electrocardiogram signals. The applications in a 2D sensor array and human-machine interaction interfaces also proved the excellent performance of this conductive hydrogels in wearable sensor.

Mechanical activation-enhanced metal-organic coordination strategy to fabricate high-performance starch/polyvinyl alcohol films by extrusion blowing

The production of high-performance starch-based packaging films by extrusion blowing is challenging, ascribed to poor processability of the blend precursors. In this study, a new strategy of mechanical activation (MA)-enhanced metal-organic coordination was proposed to improve the processability of starch (St)/polyvinyl alcohol (PVA) blend precursor, with calcium acetate (CA) as a chelating agent and glycerol as a plasticizer. MA pretreatment activated the hydroxyl groups of starch and PVA for constructing strong metal-organic coordination between CA and St/PVA during reactive extrusion, which effectively enhanced the melt processing properties of the blend precursor, contributing to the fabrication of high-performance St/PVA films by the extrusion-blowing method. The as-prepared St/PVA films exhibited excellent mechanical properties (tensile strength of 34.5 MPa; elongation at break of 271.8 %), water vapor barrier performance (water vapor permeability of 0.704 × 10−12 g·cm−1·s−1·Pa−1), and oxygen barrier performance (oxygen transmission rate of 0.7 cm3/(m2·day·bar)), along with high transmittance and good uniformity. These outstanding characteristics and performances can be attributed to the improved interfacial interaction and compatibility between the two matrix phases. This study uncovers the mechanism of MA-enhanced metal-organic coordination for improving the properties of starch-based films, which provides a convenient and eco-friendly technology for the preparation of high-performance biodegradable films.

Physicochemical and antimicrobial properties of soy protein isolate films incorporating high internal phase emulsion loaded with thymol

Oil-in-water (O/W) high internal phase (HIP) emulsion was prepared to investigate its effects on the physicochemical properties and antimicrobial properties of soy protein isolate (SPI)-based films. The particle size and migration degree of oil droplets in the SPI film-forming solution with HIP emulsion and the films were lower than those with conventional O/W emulsion or oil. The SPI-based emulsion films with HIP emulsion containing 30 % oil had the lowest water vapor permeability (1.15 × 10−10 g·m−1·s−1·Pa−1), glass transition temperature (40.93 °C) and tensile strength (4.47 MPa), and the highest transparency value (12.87) and elongation at break (160.83 %). The antimicrobial test of the SPI-based emulsion films loaded with thymol showed that the thymol encapsulation efficiency, sustained release effect, and growth inhibition effect on microbes were higher for the films with HIP emulsion than those for the films with O/W emulsion or oil.

Superhydrophobic composite membranes for membrane distillation based on CNTs networks: Overcoming the trade-off between water vapor permeability and wetting resistance

Enhancing the wetting resistance of the membrane is crucial for consolidating the stability of the membrane distillation (MD) process, but this generally leads to the decline of water vapor flux. Herein, we developed a superhydrophobic composite membrane composed of a highly hydrophobic polyvinylidene fluoride (PVDF) porous support layer and a functional superhydrophobic carbon nanotubes (CNTs) network. The CNTs network with high thermal conductivity not only reduces the temperature polarization effect, but also increases the effective evaporation area, thereby enhancing the mass transfer driving force of the MD process. Additionally, the CNTs network significantly reduces the maximum pore radius of the composite membrane, and the perfluorination treatment also reduces the surface energy of the CNTs network, thereby synergistically increasing the liquid entry pressure. The results showed that when treating high salinity water containing 3.5 wt% NaCl, the water vapor flux of the composite membrane increased from 20.0 LMH of the original PVDF membrane to 24.4 LMH, an increase of 22 %. Furthermore, the performance of the original PVDF membrane deteriorates rapidly when the concentration of surfactant in the feed exceeds 1.0 mM, while the composite membrane still maintains a stable water vapor permeability and salt rejection. More importantly, the composite membrane exhibits excellent resistance to wetting induced by gypsum scaling when using gypsum solution as the feed, which is attributed to its small surface pore size and high hydrophobicity. This research supplies new insights into the design of membrane structures used in MD processes to overcome the trade-off between water vapor permeability and wetting resistance.

Effect of chemical bonding between fluorographene and fluororesin on the anti-corrosion properties of their composite coating

Fluorographene has unique advantages in the corrosion protection of heat exchangers. Excessive fluorographene loading can ensure the thermal conductivity performance of coatings, however, it also damages the coating integrity and reduces the corrosion resistance. Therefore, the project focuses on the effects of interfacial compatibility between fluorographene and polymer on the corrosion resistance of composite coatings. Fluorographene and fluororesin have been modified to prepare composite coatings (K-PFA). This modification improves the dispersion of fluorographene in the coating matrix and enhances the interface compatibility between the two materials. The crystallinity of the composite coating has increased from 33.66 % to 40.25 %. The corrosion protection performances of K-PFA are improved due to the reduction in water vapor and oxygen permeability by 83.8 % and 73.1 %, respectively, and the coating resistance of K-PFA is 3–4 times higher than that of blank coating. By utilizing surface modification techniques, the interface compatibility between fluorographene and the coating has been optimized, resulting in enhanced anti-corrosion properties for coatings.

Water and Oxygen Barrier Properties of All-Cellulose Nanocomposites.

Hydroxypropyl cellulose (HPC) is potentially interesting as a biobased, rigid food packaging material, but its stiffness and strength are somewhat low, and its water and oxygen transport rates are too high. To improve these characteristics, we investigated nanocomposites of HPC and cellulose nanocrystals (CNCs). These high-aspect-ratio nanoparticles display high stiffness and strength, and their high crystallinity renders them virtually impermeable. Exchanging the counterions of sulfate-ester decorated CNCs with cetyltrimethylammonium ions affords particles that are dispersible in ethanol (CTA.CNC) and allows solvent casting of HPC/CTA.CNC nanocomposite films, which, even at a CTA.CNC content of 90 wt %, are highly transparent. The introduction of CTA.CNC considerably increases the Young's modulus (Ey) and upper tensile strength (σUTS). For example, in the nanocomposite with 90% CTA.CNC, Ey = 7.6 GPa is increased 20-fold and σUTS = 42.7 MPa is more than doubled in comparison to HPC, whereas the extensibility (1.1%) remains appreciable. Composites with a CTA.CNC content of 70 wt % or less show a lower water vapor permeability (6.4-9.2 × 10-5 g μm m-2 s-1 Pa-1) than the neat HPC (1.5 × 10-4 g μm m-2 s-1 Pa-1), whereas the oxygen permeability (5.6 × 10-7-1.3 × 10-6 cm3 μm m-2 s-1 Pa-1) is reduced by 1 order of magnitude compared to HPC (3.2 × 10-6 cm3 μm m-2 s-1 Pa-1). The biobased nanocomposites retain their mechanical integrity at a relative humidity of 75% but readily disintegrate in water.

Potential of Pinhão husk (Araucaria angustifolia) as a structural reinforcement agent in the properties of edible films of Pinhão flour and gelatin

AbstractIn this study, the use of Pinhão husk as a source of reinforcement material for development of edible films, where the Pinhão seed flour and bovine gelatin were used as matrices for the films. Mechanical properties, water vapor permeability, solubility and opacity, microstructure, and thermal degradation characterized the films produced. The films presented homogeneous and cohesive structures. Pinhão husk content positively affected film properties by increasing tensile strength (TS) and decreasing water vapor permeability (WVP), with Pinhão flour film formulations (5.0% Pinhão flour, 1.2% glycerol, and 0.4% Pinhão husk) and gelatin (5.0% gelatin, 2.0% glycerol, and 0.4% Pinhão husk) those that presented the best results (5.06 MPa for TS and 0.14 g.mm/kPa.h.m2 for WVP) and (3.88 MPa for TS and 0.28 g.mm/kPa.h.m2 for WVP), respectively The thermal degradation study revealed that the films are stable at temperatures below 150°C, losing only free water and volatile compounds of low molecular weight. Pinhão husk can reinforce films, making them suitable as biodegradable and edible packaging materials for eco‐friendly food products. This contributes to the circular economy, preserves biodiversity, and reduces plastic waste, offering promising sustainable packaging solutions.