Water Vapor Permeability Research Articles

Chitosan-Based Coating Incorporated with Chitin Nanofibers for Extension of the Shelf Life of Fruits

Chitin is the second most abundant biopolymer in the world. Herein, deacetylated chitin nanofibers (dChNFs) through partial deacetylation were initially prepared, and dChNFs were subsequently added into chitosan (CS) to develop the biodegradable coatings to extend the shelf life of bananas. The degree of deacetylation and the average diameter of the obtained dChNFs were 29.12 % and 19.49 ± 3.1 nm, respectively. The addition of dChNFs into CS at the ratio of 50:50 decreased the water vapor permeability (WVP) from 4.56 × 10–11 g/m·s·Pa to 3.81 × 10–11 g/m·s·Pa. Moreover, three different suspensions of CS, dChNFs, and CS/dChNFs were applied as coatings on Hom–Thong bananas via the dipping technique. The application of the CS/dChNFs coating showed a significant postponement in the color change of the peel (from green to yellow) to 22 days, compared to 9 days for uncoated bananas. The weight of the bananas coated with CS/dChNFs exhibited a weight loss of 26.53 % day–1, which was lower than that of the uncoated bananas (30.71 % day–1). This suggested that the CS/dChNFs coating would be efficiently used to prolong the shelf life of bananas, reducing food waste.

Properties of an active film based on chitosan/silk fibroin loaded with an essential oil microemulsion and its application in preservation of strawberries

This study aimed to enhance the weak antibacterial activity of silk fibroin (SF) by creating a composite edible coating film. The film was composed of chitosan (CS), SF, and a 3% (v/v) cinnamon essential oil microemulsion (CEOM), which showed excellent inhibition rates of over 99% against two bacteria and four fungi. The resulting film had a transparency of 84.6% and a contact angle of 61.85° on hydrophobic surfaces. In addition, it exhibited a low water vapor permeability of 1.09 × 10−12 g·cm−1·s−1·Pa−1. These properties make it ideal for use in food coating applications. To assess the preservation capabilities of the composite films, strawberries were coated with different films: CS, SF, SF-CEOM, and SF-CS-CEOM. The results showed that the SF-CS-CEOM film had a similar effect to the SF-CEOM film in suppressing the deterioration of strawberries, when compared to the untreated group, and the shelf life of the strawberries was extended from 2 days to 8 days. The SF-CS-CEOM film inhibits oxidation and metabolism by reducing gas exchange, thereby protecting the integrity of cell membranes, maintaining firmness, and reducing weight loss, while delaying the onset of spoilage by inhibiting microbial growth.

Development and characterization of gelatin-based biodegradable films incorporated with pistachio shell hemicellulose

This study aimed to incorporate pistachio shell hemicellulose into a film of gelatin and glycerol for the production of biodegradable films. The gelatin and glycerol are chosen because of their functional properties, which make it extensively used in food industry. The film composition was defined after a statistical optimization by central composite face-centered design and response surface methodology. The hemicellulose/gelatin ratio of 35.93% and the glycerol ratio of 18.02% were the optimum conditions to obtain lower film water solubility, higher tensile strength, and elongation at break values. The physical, structural, mechanical, and barrier properties of the developed hemicellulose-gelatin film were analyzed and compared with those of the gelatin film. Tensile strength and film water solubility values were reduced significantly with hemicellulose incorporation from 20.41 to 16.64 MPa and 49.57 to 39.21%, respectively, while EB was enhanced by 4.34 times. In addition, hemicellulose incorporation enhanced the water vapor permeability and the film degradation in the soil. The films were also examined by Fourier transform infrared spectroscopy and differential scanning calorimetry. The novelty of this study is to use pistcahio shell hemicellulose in the production of an edible film for the first time.

Evaluation of the Effect of the Composition of the Foam Glass Concrete on Its Flammability and Moisture Characteristics

The purpose of this study was to evaluate the moisture and flammability characteristics of lightweight concrete with different aggregates and different amounts of cement according to different criteria. The moisture properties of the specimens were evaluated by the coefficient of water absorption due to capillary action, short-term water absorption, and water vapour permeability. Short-term water absorption correlated with the density of the specimens, and capillary absorption was evaluated depending on the soaking time, amount of cement, and type of lightweight aggregate. The values of the water vapour diffusion resistance factor were estimated based on the amount of cement, the type of lightweight aggregate, the density, and the porosity. The porosity correlated with the amount of cement and the type of lightweight aggregate. The flammability properties of concrete with lightweight aggregate were evaluated by several methods, such as the single flame source test, the single burning item test, and the non-combustibility test. After assessing the flammability characteristics, a structure analysis of the samples was specifically performed to assess the processes that occur during the combustion of lightweight concrete. It was found that short-term water absorption depended mainly on the density, capillary absorption on the amount of cement, and the water vapour diffusion resistance factor, flammability, and thermal stability of lightweight concrete on the type of granules.

Translucent superhydrophobic coating for murals protection

This study aims to protect murals by a translucent and superhydrophobic coating using a one-step spraying process, which offers simplicity, efficiency, and cost-effectiveness, while preserving the mural's visual appeal and safeguarding against moisture. Despite numerous advancements in cultural relic conservation, the application of super-hydrophobic coatings for mural preservation remains a novel approach. The coating consists of acrylic resin (Paraloid B72), nano-silica, and polydimethylsiloxane (PDMS). The optimal amounts of silica and PDMS were 3 g each in a basal solution containing 12 g of acrylic resin dissolved in 88 mL of xylene. The resulting composite coating displayed exceptional water repellency, as indicated by a contact angle of 165.5° and a rolling angle of approx. 7°. As a result, the moisture absorption of the mural decreased significantly from ∼53% to ∼5% after the application of the superhydrophobic coating. The coating had minimal impact on the water vapor permeability of the mural, with a ca. 13% decline rate. The coating is translucent with a visible transmittance of approximately 60%. Therefore, the coated mural maintains its original appearance with minimal changes. Furthermore, the superhydrophobic properties of the coating remain intact even after undergoing five cycles of high-low temperature fatigue tests, 196 hours of ultraviolet irradiation, or seven cycles of sand impacting.

Multipurpose arrowroot starch films with anthocyanin-rich grape pomace extract: Color migration for food simulants and monitoring the freshness of fish meat

Extraction of anthocyanins from grape pomace, is a way of valuing these abundant by-products with low added value. Its integration into films may allow it to be used in bioactive packaging, which creates new color and solubility properties for food and smart food packaging which tracks the freshness of fish. Films of arrowroot starch added with different concentrations of grape pomace extract (GPE) were flexible to handle, reddish and presented a high content of anthocyanins. The water vapor permeability increased by 17 %, while the tensile strength of arrowroot starch film decreased by 79 % with the addition of 40 % GPE. The addition of GPE increased the solubility of the starch film in aqueous and lipid food simulants by 121 and 119 %. The GPE pigment preferentially migrated to the aqueous simulant due to the hydrophilic nature of anthocyanins and starch. The GPE film showed distinguishable color changes in different pH buffer solutions from pink at pH 2 to light blue at pH 7 and slightly yellowish green at pH 10. When the composite films were monitored for fish meat freshness, the change in color of the film from reddish pink to slightly green after 96 h of storage at 25 °C was evident.

Developing a novel, low-cost, antimicrobial, and biodegradable pectin/HEC/ZnO biofilm for edible food packaging applications

AbstractThe purpose of this study was to investigate the potential of pectin extracted from orange waste by acid hydrolysis and prepared Pectin/ hydroxyethyl cellulose (HEC)/ZnO nanoparticles (ZnO-NPs) biofilm for food packaging applications. The pectin/HEC/ZnO biofilms were prepared in an aqueous solution at room temperature using solvent casting method and characterized by different techniques such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscope (SEM). Also, thermal gravimetric analysis (TGA), mechanical properties, and water vapor permeability-WVP were evaluated. Moreover, its antimicrobial activity against Gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Salmonella enterica Typhimiurium) and two Gram positive bacteria (Listeria monocytogenes and Staphylococcus aureus), and also has antifungal activity against Candida albicans was assessed. The obtained results display that the water vapor permeability (WVP) indicated a reduction in permeability with increased ZnO concentration, with WVPs ranging from 2.55 × 10−12 to 4.28 × 10−12 gm/pas.m2, which indicates that our pectin/HEC/ZnO bionanocomposite biofilm could efficiently decrease moisture transfer, thereby potentially extending the shelf-life of packaged food products. Furthermore, the results showed enhanced tensile strength and flexibility in the biofilms with the addition of 1% ZnO nanoparticles from 1.2 to 2.6 MPa and 4.5 to 13 MPa respectively. The WVP indicated a reduction in permeability with increased ZnO concentration, with WVPs ranging from 2.55 × 10−12 to 4.28 × 10−12 gm/pas.m2. The antimicrobial activity against pathogens such as Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica Typhimurium, Listeria monocytogenes, Staphylococcus aureus, and Candida albicans was significant, with a 99.96% reduction in E. coli counts at a biofilm concentration of 200 mg/mL. Furthermore, the current study revealed that the synthesized bionanocomposite biofilms had excellent qualities such as transparency, flexibility, low cost, and being environmentally friendly. The pectin/HEC/ZnO bionanocomposite was found to be an ideal biofilm for food packaging due to its safety and affordability, which is able to prolong food shelf-life.

Linear regression analysis of properties related to moisture management using cotton–polyester knitted fabrics

The complex evaluation of thermo-physiological comfort for a particular garment is still challenging, as it depends on the different structural parameters and individual properties of textiles. Measurement of relevant fabric characteristics requires very specific laboratory equipment, such as an M 290 moisture management tester (SDL ATLAS) or similar. For this reason, it is obvious that there is a great demand to predict the overall moisture management capability ( OMMC) based on the individual properties that are responsible for clothing comfort and testing according to different standards rather than OMMC-specific calculation using the M 290 tester. Therefore, in this research, linear regression analysis was performed using MATLAB software to predict the OMMC for cotton–polyester fabrics knitted in two patterns, namely 1 × 1 rib and half-Milano rib, using four percentages of fibers. Water vapor permeability, water vapor resistance, water absorption capacity, water absorption time, and air permeability were used as input variables for linear regression analysis to predict the OMMC of fabrics. The performed analysis has shown that the OMMC is directly dependent on the relative water vapor permeability and air permeability, and the linear regression equation suggested in this research can predict the suitability of a textile for a particular garment concerning its moisture management behavior.

Development of carboxymethyl cellulose-based nanocomposite incorporated with ZnO nanoparticles synthesized by cress seed mucilage as green surfactant

This study aimed to enhance carboxymethyl cellulose (CMC)-based films by incorporating zinc oxide nanoparticles (ZnO NPs) and cress seed mucilage (CSM), with a view to augmenting the physical, mechanical, and permeability properties of the resulting nanocomposite films. For the first time, CSM was exploited as a green surfactant to synthetize ZnO NPs using hydrothermal method. Seven distinct film samples were meticulously produced and subjected to a comprehensive array of analyses. The findings revealed that the incorporation of CSM/ZnO-5 % improved the physical properties of the films, demonstrating a significant reduction in moisture content and water vapor permeability (WVP). Increasing the concentration of NPs in conjunction with CSM markedly decreased the solubility of the nanocomposites by up to 56 %. The films containing CSM/ZnO showed higher tensile strength and elongation at the break values. The UV absorption of the films exhibited a substantial rise with the addition of ZnO NPs, particularly with an increased content in the presence of CSM. The thermal stability of nanocomposites containing a high concentration of CSM/ZnO exhibited an improvement compared to the control sample. In light of these results, the CMC/CSM/ZnO-5 % film emerges as a promising candidate for a biocompatible packaging material, exhibiting favorable physical characteristics.

Novel films of pectin extracted from ambarella fruit peel and jackfruit seed slimy sheath: Effect of ionic crosslinking on the properties of pectin film

Here, we prepared ionically crosslinked films using pectin extracted from agro-wastes, specifically ambarella peels (AFP) and jackfruit seed slimy sheath (JFS). Physiochemical properties of pectins, including moisture content, molecular weight (Mw), degree of esterification (DE), and galacturonic acid (GA), were analyzed. Optimal extraction was determined, i.e., citric acid concentration 0.3 M, time 60 min, solid/liquid ratio 1:25, and temperature 90 °C for AFP or 85 °C for JFS. Pectin yields under these conditions were 29.67 % ± 0.35 % and 29.93 ± 0.49 %, respectively. AFP pectin revealed Mw, DE, and GA values of 533.20 kDa, 67.08 % ± 0.68 %, and 75.39 ± 0.82 %, while JFS pectin exhibited values of 859.94 kDa, 63.04 % ± 0.47 %, and 78.63 % ± 0.71 %, respectively. The pectin films crosslinked with Ca2+, Cu2+, Fe3+, or Zn2+ exhibited enhanced tensile strength and Young's modulus, along with reduced elongation at break, moisture content, water solubility, water vapor permeability, and oxygen permeability. Structural analyses indicated metal ions were effectively crosslinked with carboxyl groups of pectin. Notably, the Cu2+-crosslinked film demonstrated superior water resistance, mechanical properties, and exhibited the highest antioxidant and antibacterial activities among all tested films. Therefore, the pectin films represent a promising avenue to produce eco-friendly food packaging materials with excellent properties.

Flexible cellulose nanofibers/MXene composite films for UV-shielding packaging

Cellulose nanofibers (CNF) based films are promising packaging materials, but the lack of special functions (especially UV-shielding property) usually restrict their further applications. In this work, MXene was incorporated into the CNF film by a direct solvent volatilization induced film forming method to study its UV-shielding property for the first time, which avoided the using of a vacuum filtration equipment. The composite films containing glycerin could be folded repeatedly without breaking, showing good flexibility. The structure and properties of MXene/CNF composite films (CMF) were characterized systematically. The results showed that MXene distributed uniformly in the CNF film matrix and there was strong hydrogen bonding interaction between CNF and MXene. The tensile strength and Young's modulus of the composite films could reach 117.5 MPa and 2.23 GPa, which was 54.1 % and 59.2 % higher than those of pure CNF film, respectively. With the increase of MXene content, both the UVA and UVB shielding percentages increased significantly from 17.2 % and 25.5 % to 100.0 %, showing excellent UV-shielding property. Moreover, CMF exhibited a low oxygen permeability (OP) value of 0.39 cc μm d−1 m−2 kPa−1, a low water vapor permeability (WVP) value of 5.13 × 10−11 g−1s−1Pa−1 and a high antibacterial rate against E. coli (94.1 % at 24 h), showing potential application in the packaging field.

Sodium-alginate-based indicator film containing a hydrophobic nanosilica layer for monitoring fish freshness

In this study, hydrophobic sodium alginate/anthocyanin/cellulose nanocrystal indicator films were fabricated by incorporating nanosilica (NS) as a waterproofing layer. The concentrations and formation methods (spraying (S), coating (C), and impregnation (I)) of the NS layer (denoted as NSS, NSC, NSI, respectively) were optimized. The results indicated that the optimum concentration of the NS layer was 5 % at a water contact angle (WCA) 110.5°. Further, Fourier transform infrared spectra showed the presence of SiOSi and SiCH3 groups in the NSS, NSC, and NSI films, and X-ray diffraction spectra indicated that original structures of these films were disordered. Moreover, the surface morphology, mechanical properties, and light transmission were affected by the NS layer, and the optimal layer was found to be NSI. After 10 days of storage at 100 % humidity, the NSI film exhibited low water vapor adsorption (37.22 g) and permeability (0.1484 g/m·s·Pa·10−11) and a high WCA (110.2°). In addition, the NSI film exhibited a visible color shift with an increasing pH of the buffer solution. A monitoring test of fish freshness showed that the NSI film displayed a distinctive color change corresponding to fish spoilage during 14 days of storage. This indicates that NSI has high potential in indicator film applications.

Green and facile fabrication of multifunctional cellulose nanocrystal and carvacrol together reinforced chitosan bio-nanocomposite coatings for fruit preservation

The continuous development of sustainable food-active packaging materials and practices with high performance is a response to the increasing challenges posed by microbial food safety and environmental contamination. In this study, a multifunctional bio-nanocomposite composed primarily of chitosan, cellulose nanomaterials and carvacrol was proposed as a conformal coating for fruit preservation. The coating exhibits excellent antioxidant and antibacterial activities owing to the incorporation of the carvacrol. The inhibition rate of the coating on E. coli and S. aureus is enhanced by 57.13 % and 62.18 %, respectively. And its antioxidant activities is also improved by 77.45 %. In addition, the oxygen permeability (OP) and water vapor permeability (WVP) of this CS/CNC coating are significantly lowered by 67 % and 46 %, respectively, comparing with the CS coating. The coating exhibited excellent biosafety and cytocompatibility because of over 90 % of the HepG2 cells remained alive in each concentration of the coating after 24 h incubation. Additionally, the efficacy of the coating in prolonging the freshness and visual appeal of perishable fruits is substantiated by the experiment involving two fruit specimens. Furthermore, the coating's ease of production, ingestibility, washability, and utilization of cost-effective and easily accessible biomaterials, including renewable waste materials, indicate its potential as a viable economic substitute for commercially accessible fruit coatings.

Investigation of physio-mechanical, antioxidant and antimicrobial properties of starch–zinc oxide nanoparticles active films reinforced with Ferula gummosa Boiss essential oil

The production of surface compounds coated with active substances has gained significant attention in recent years. This study investigated the physical, mechanical, antioxidant, and antimicrobial properties of a composite made of starch and zinc oxide nanoparticles (ZnO NPs) containing various concentrations of Ferula gummosa essential oil (0.5%, 1%, and 1.5%). The addition of ZnO NPs improved the thickness, mechanical and microbial properties, and reduced the water vapor permeability of the starch active film. The addition of F. gummosa essential oil to the starch nanocomposite decreased the water vapor permeability from 6.25 to 5.63 g mm−2 d−1 kPa−1, but this decrease was significant only at the concentration of 1.5% of essential oils (p < 0.05). Adding 1.5% of F. gummosa essential oil to starch nanocomposite led to a decrease in Tensile Strength value, while an increase in Elongation at Break values was observed. The results of the antimicrobial activity of the nanocomposite revealed that the pure starch film did not show any lack of growth zone. The addition of ZnO NPs to the starch matrix resulted in antimicrobial activity on both studied bacteria (Staphylococcus aureus and Escherichia coli). The highest antimicrobial activity was observed in the starch/ZnO NPs film containing 1.5% essential oil with an inhibition zone of 340 mm2 on S. aureus. Antioxidant activity increased significantly with increasing concentration of F. gummosa essential oil (P < 0.05). The film containing 1.5% essential oil had the highest (50.5%) antioxidant activity. Coating also improved the chemical characteristics of fish fillet. In conclusion, the starch nanocomposite containing ZnO NPs and F. gummosa essential oil has the potential to be used in the aquatic packaging industry.

Fabrication and characterization of chitosan/anthocyanin intelligent packaging film fortified by cellulose nanocrystal for shrimp preservation and visual freshness monitoring

In this study, a multi-functional packaging film was fabricated, utilizing the natural polysaccharide chitosan (CS) as the base material, integrating natural blueberry anthocyanin (AN) as pH-responsive indicator, and reinforced with cellulose nanocrystals (CNCs). The implications of addition levels of CNCs on the characteristics of the films were systematically investigated, resulting in that CS-AN-CNCs 9 % film exhibited optimal performance. Specifically, the film showed a substantial enhancement in maximum tensile strength from 15 MPa to 35 MPa; On the other hand, the swelling degree properties, the oxygen permeability and water vapor permeability decreased from 159.2 % to 92.0 %, from 51.7 g/(m2d) to 12.2 g/(m2d), from 31.6 × 10−12 g/(m·s·Pa) to 1.6 × 10−12 g/(m·s·Pa), respectively. Moreover, the CS-AN-CNCs 9 % film exhibited antioxidant, antibacterial, coupled with a color metrically responsive to pH variations, displaying great potential in indicating the shrimp freshness and delaying spoilage. Another notable advantage of the-prepared packaging material lies in its completely biodegradability, therefore meeting the requirement of environmental protection. Therefore, the prepared CS-AN-CNCs film as an intelligent packaging solution with potential applications in food preservation and freshness monitoring applications.

Engineered composite dressing with exudate management capabilities for the process of entire wound healing

A timely antibacterial dressing that can adapt to dynamic wound environments poses a significant challenge in burn research and management. Herein, a four-layered composite dressing is reported. At its core, it features a modified micropore arrayed Janus membrane with a super-hydrophobic polyurethane layer on one side and a super-hydrophilic hydrogel on the other. This unique design enables the dressing to maintain stable and durable self-pumping capabilities, effectively transferring wound exudate to the upper foam layer. The self-pumping rate exceeds that of traditional foam dressings, being approximately 1.39 times more efficient in absorbing excess wound exudate. The composite dressing demonstrates an impressive water donation capacity when tested on 45% gelatin-simulated skin, achieving a water donation rate of (59.20 ± 2.66)%. Furthermore, the water vapor permeability of the composite dressing outperforms hydrocolloids by approximately 3.66 times. Additionally, the composite dressing, when loaded with super-hydrophilic nanometer zinc oxide, exhibits a potent antibacterial effect. The dressing's surface reduces cellular, platelet, fibrinogen, and bovine serum albumin adhesion, reducing the risk of tissue adhesion. During a 20-day trial covering deep II-degree burn wounds, the dressing demonstrated excellent biocompatibility. It effectively compresses the inflammatory phase, promotes vascularization, and significantly accelerates the regeneration of skin accessory organs. This innovative dressing exhibits great potential for use throughout the entire wound-healing process in future burn treatments.

Characterization of extruded films based on poly (butylene succinate) blends to utilize a partially degraded poly (butylene adipate‐co‐terephthalate)

AbstractPolymer blends can improve material processability and can be used to extrude partially degraded materials, such as expired poly (butylene adipate‐co‐terephthalate) (PBAT), which cannot be normally extruded. Therefore, in this study, the extrudability of PBAT that has passed its expiration date was restored by blending it with poly (butylene succinate) (PBS). Various polymer blends were extruded and characterized to achieve high‐efficiency extrusion. The carbonyl indices in partially degraded PBAT and the corresponding control sample detailed the effects of 98 months of aging on molecular properties. The semicrystalline structure consisted of a mixed ordered arrangement of PBS and PBAT chains dispersed in an amorphous matrix. The microscopic images of the surfaces of the polymer films revealed defects and roughness, followed by an increase in the PBAT concentration in blends. Changes in mechanical properties and water vapor permeability correlated with the PBAT concentration in the blends. To avoid polymer loss, we reported a simple method for using PBAT that has passed its expiration date and cannot be extruded. The results revealed that the polymer films could be used in the packaging industry, especially in food and agricultural sectors.

Barrier, Mechanical, Thermal, and Rheological Properties of Plasticized Biopolymeric Films Manufactured by Co-Extrusion

The thermal, rheological, mechanical, and barrier properties of flat biopolymeric films processed by extrusion with different proportions of plasticizer and surfactant were evaluated. In the first stage, pellets were developed through twin-screw extrusion using a temperature profile in the ascending step process. These samples were analyzed using rotational rheology analysis to understand the viscoelastic transitions through the behavior of the storage and loss modulus, as well as the incidence of complex viscosity concerning concentration. The interaction among the components was analyzed under infrared spectroscopy after the two processing stages, revealing the miscibility of the mixture due to the action of the surfactant. The degradation temperatures increased by more than 20 °C, generating thermal stability, and the temperatures related to polymer transitions were determined. In the second stage, co-extrusion was carried out using pellets from the blend with a melt flow index (MFI) suitable for this process. The samples TPS50-PLA50-T5 and TPS75-PLA25-T5-A10 presented MFI values of 2.27 and 1.72 g/10 min, respectively. These samples were co-extruded for the production of films, impacting the physical properties. The resistance to traction, Young’s modulus, and elongation showed limited effectiveness of plasticizer and surfactant, with high resistance and elongation values (4.276 MPa and 2.63%) in the TPS50-PLA50-T5 film. Additionally, morphological analysis showed the detailed action of the plasticizer on the regular shapes of threads as a product of deformation during material processing. The barrel properties exhibited limited biopolymer–plastic–tensile miscibility, resulting in different water vapor permeability for the TPS75-PLA25-T5-A10 film on each side (a difference of two orders of magnitude). The contact angle corroborated the effect, with values in each case ranging from 103.7° to 30.3°. In conclusion, we assert that biopolymeric films, when modified with plasticizers and surfactants, can be tailored for various applications within the packaging sector while maintaining control over each film.

Safe and sustainable food packaging: Argemone albiflora mediated green synthesized silver-carrageenan nanocomposite films

Silver-Carrageenan (Ag/Carr) nanocomposite film for food packing application by the green method using Argemone albiflora leaf extract has been developed in this study. Different plant parts of Argemone albiflora (blue stem prickly poppy) are used all over the world for the treatment of microbial infections, jaundice, skin diseases etc. GC–MS analysis was used to examine the phytochemical found in the Argemone albiflora leaf extract which reduces the metal ions to nanoscale. The biopolymer employed in the synthesis of nanocomposite film was carrageenan, a natural carbohydrate (polysaccharide) extracted from edible red seaweeds. We developed a food packing that is biodegradable, eco-friendly, economical and free from harmful chemicals. These films possess better UV barrier and mechanical and antimicrobial properties with 1 mM AgNO3 solution. The presence of silver nanoparticles in the carrageenan matrix was evident from FESEM. The mechanical properties were analysed by a Universal testing machine (UTM) and different properties like water vapour permeability (WVP), moisture content (MC) and total soluble matter (TSM) important for food packing applications were also analysed. The antimicrobial properties of the synthesized film samples were studied against E. coli and S. aureus pathogenic bacteria. These films were employed for the storage of cottage cheese (dairy product) and strawberries (fruit). This packing increased the shelf life of the packed food effectively. Ag/Carr films are biodegradable within four weeks.

Biodegradable films from the lignocellulosic fibers of wheat straw biomass and the effect of calcium ions

Plastics are hazardous to human health, and plastic waste results in environmental pollution and ecological catastrophe. Biobased polymers from renewable sources have recently become promising for developing biodegradable packaging films. Among them, lignocellulosic residue from agricultural biomass is inexpensive, renewable, and biodegradable. This study aims to develop biodegradable films using lignocellulosic residue from wheat straw biomass. The methodology is a green process that solubilizes lignocellulosic chains using Zn2+ ions and crosslinks with Ca2+ ions of different concentrations (200–800 mM). The results reveal that the increase of Ca2+ ions significantly decreases moisture content, water solubility, water vapor permeability, transparency, and elongation of films. The tensile strength is recorded as 6.61 ± 0.07 MPa with the addition of 800 mM of CaCl2, which is approximately 2.5 times higher than commercial polyethylene films. Around 90 % of films biodegrade within a month in soil containing 20 % moisture content. Overall, lignocellulosic residue from wheat straw biomass could be an excellent replacement for synthetic polymer to fabricate strong, transparent, and biodegradable plastic films.