Water Vapor Permeability Rate Research Articles

PREPARATION, CHARACTERIZATION AND ANALYSIS OF NANOSCALE MORPHOLOGY OF POLY(VINYL ALCOHOL) FILMS ASSOCIATED WITH SILK FIBROIN FUNCTIONALIZED WITH COPAÍBA OLEORESIN

Biodegradable films based on poly(vinyl alcohol) (PVA) and bioactive substances have been receiving great attention in the food industry, as they offer an eco-friendly alternative to conventional packaging. In this context, we synthesized PVA (PVAF) films containing silk fibroin (SF) formulations functionalized with copaiba oleoresin (CO) for use as bioactive packaging. Four different formulations were prepared using the casting method, varying the SF-CO concentrations from 0 to 15% (v/v) in the PVA matrix. The samples were characterized regarding morphology, nanotexture, physicochemical, and barrier properties. SEM images revealed the uniform morphology of the films, and AFM data allowed the quantification of surface characteristics such as uniformity and homogeneity, confirming the uniform distribution of SF-OC in the PVA matrix. All films showed high water absorption power (more than twice their mass weight), and the incorporation of SF-CO did not change the water vapor permeability rate of PVAF. In contrast, the solubility of PVAF decreases with SF-CO content. FTIR and UV-vis spectra confirmed the presence of SF-CO in PVAF and indicated possible intermolecular interactions between PVA and SF-CO. Finally, our findings suggest that the incorporation of SF-CO into the PVA matrix is a viable alternative for producing eco-friendly packaging.

Preparation and characterization of poly(vinyl pyrrolidone)/cellulose nanofiber/Aloe Vera composites as a biocompatible hydrating facial mask.

This study aimed to enhance the properties of polyvinylpyrrolidone (PVP) for use as biocompatible facial masks. To achieve this, nanofibers were developed by blending PVP with cellulose nanofibers (CNFs) and Aloe vera (AV) powder using electrospinning. The results showed that incorporating CNFs and AV into the PVP matrix led to the formation of smooth and uniform nanofibers. In particular, adding 3-6wt% AV powder in PVP/CNF composites improved fiber diameter distribution and uniformity compared to pure PVP. The PVP/CNF/AV nanofibers exhibited desirable properties for facial mask applications. They displayed 86-93% porosity, which allowed for efficient moisture absorption capacity of up to 1829%, and excellent water vapor permeability rate of 3.92g/m2h. The mechanical properties of the electrospun nanofiber composites were evaluated through tensile testing. The results showed that Young's modulus values decreased progressively with the addition of CNFs and AV powder to the PVP polymer matrix, indicating a plasticizing effect that enhances flexibility. The fracture strain remained similar across all composites, suggesting that CNFs and AV did not significantly weaken the PVP matrix. The tensile strength initially increased with CNF addition but decreased with incremental AV loading. Biocompatibility studies revealed that all nanofibers exhibited excellent fibroblast viability, surpassing 98%. This indicates that incorporating CNFs and AV did not compromise cell viability, further highlighting the suitability of the PVP/CNF/AV composites for facial mask applications.

Chitosan based ethanolic Allium Sativum extract hydrogel film: a novel skin tissue regeneration platform for 2nd degree burn wound healing

This study investigated the potential of ethanolic garlic extract-loaded chitosan hydrogel film for burn wound healing in an animal model. The ethanolic garlic extract was prepared by macerating fresh ground garlic cloves in ethanol for 24 h, followed by filtration and concentration using a rotary evaporator. Hydrogels were then prepared by casting a chitosan solution with garlic extract added at varying concentrations for optimization and, following drying, subjected to various characterization tests, including moisture adsorption (MA), water vapor transmission rate (WVTR), and water vapor permeability rate (WVPR), erosion, swelling, tensile strength, vibrational, and thermal analysis, and surface morphology. The optimized hydrogel (G2) was then analyzed in vivo for its potential for healing 2nd degree burn wounds in rats, and histological examination of skin samples on day 14 of the healing period. Results showed optimized hydrogel (G2; chitosan: 2 g, garlic extract: 1 g) had MA of 56.8% ± 2.7%, WVTR and WVPR of 0.00074 ± 0.0002, and 0.000 498 946 ± 0.0001, eroded up to 11.3% ± 0.05%, 80.7% ± 0.04% of swelling index, and tensile strength of 16.6 ± 0.9 MPa, which could be attributed to the formation of additional linkages between formulation ingredients and garlic extract constituents at OH/NH and C=O, translating into an increase in transition melting temperature and enthalpy (ΔT = 238.83 °C ± 1.2 °C, ΔH = 4.95 ± 0.8 J g−1) of the chitosan moieties compared with blank. Animal testing revealed G2 formulation significantly reduced the wound size within 14 d of the experiment (37.3 ± 6.8–187.5 ± 21.5 mm2) and had significantly higher reepithelization (86.3 ± 6.8–26.8 ± 21.5 and 38.2% ± 15.3%) compared to untreated and blank groups by hastening uniform and compact deposition of collagen fibers at the wound site, cementing developed formulation a promising platform for skin regeneration.

Blends of Carboxymethyl Cellulose and Cottonseed Protein as Biodegradable Films.

With the increasing awareness of plastic pollution in the environment and the accumulation of microplastics in water, a significant amount of research and development is ongoing to replace the synthetic plastics in packaging and coatings. In this work, we explored the blends of carboxymethyl cellulose (CMC) and washed cottonseed meal (CSM, consisting mostly of cottonseed protein) as agro-based, biodegradable, and sustainable alternatives to plastics. Glycerol was found to be a suitable plasticizer for these blends. The blends of CMC/CSM were produced as single-layer films from 50 to 90 μm in thickness, consisting of different proportions of the components and plasticizer. The evaluated properties included opacity, water vapor permeability, mechanical properties, thermogravimetric analysis, moisture sorption analysis, and water swelling test. Higher percentages of CSM in the blend resulted in higher opacity and lower water vapor permeation rates. The mechanical strength waned with lower levels of CMC. Possible applications for these blends include their use as water-soluble food packaging and coatings and as dissolvable bags and pouches for detergents and agrochemicals.

Development of thymol-loaded polymeric films designed as wound dressing materials: Physical, antioxidant, antibacterial, cytocompatibility, and wound healing properties

In the presented study, the potential of thymol-loaded films consisting of pullulan (PUL) and kappa carrageenan (CARR) to be used as wound dressing materials was examined. The films were characterized by FTIR (Fourier transform infrared), TGA (thermogravimetric analysis) and SEM (scanning electron microscopy) analyses. Swelling and hydrolytic degradation behavior, water vapor permeability rate, and mechanical properties, which are important parameters for the films to be evaluated as wound dressing materials, were determined. Antioxidant and antibacterial activities of the films were examined. Additionally, in vitro cytotoxicity and in vitro wound healing activity of the films were evaluated in the L929 fibroblast cell line. The results show that the non-toxic biopolymeric film containing 5 % thymol has the potential to be a promising antioxidant and antibacterial wound dressing, effectively reducing the scratch open area for wound dressing application.

Alginate-coated functional wrapping paper incorporated with sulfur quantum dots and grapefruit seed extract for preservation of potato hash browns

This study explores the impact of alginate-based functional coatings incorporating sulfur quantum dots (SQDs) and grapefruit seed extract (GFSE) on the antioxidant and antibacterial properties of kraft paper for food packaging. Applying these coatings effectively fills the porous interfibrillar spaces of the paper, significantly improving oil resistance and mechanical properties. However, the water vapor permeability and moisture absorption rate decreased slightly due to the hydrophilic nature of constituents. In particular, the addition of 5 wt% SQDs to the paper coating formulation resulted in remarkable antioxidant activity, with approximately 100% reduction in ABTS and 60% reduction in DPPH free radicals. The addition of SQDs significantly reduced the bacterial cell viability of E. coli and L. monocytogenes by ∼2 log CFU/mL and ∼4.5 log CFU/mL, respectively. Co-addition of SQDs and GFSE significantly improved antimicrobial activity with ∼3 log CFU/mL reduction of E. coli and complete (100%) eradication of L. monocytogenes even at lower concentrations (2.5 wt% each). The lipid oxidation in the hash brown potato patties wrapped in functional coated paper was reduced by nearly 50% compared to uncoated paper. This effect persisted even after an extended storage period of 15 days, demonstrating the superior ability of the coated paper to improve the shelf life of processed, ready-to-eat foods.

Chrysin loaded polycaprolactone-chitosan electrospun nanofibers as potential antimicrobial wound dressing

In this study, various concentrations of chrysin (chry) were loaded into polycaprolactone-chitosan (PCL-CTS) nanofibers to develop a potential wound dressing materials using electrospinning method. The structural composition and the morphology of the produced PCL-CTS5, PCL-CTS10 and PCL-CTS15 were analyzed by FE-SEM and FTIR, respectively. By increasing the amount of chry, the average diameter of the nanofibres was also increased to 191 ± 65 nm, 203 ± 72 nm, and 313 ± 69 nm for PCL-CTS5, PCL-CTS10, and PCL-CTS15, respectively. Moreover, the physicochemical characteristics and biological properties of synthesized nanofibers such as tensile testing, in-vitro drug release, porosity, decomposition rate, water absorption rate, water vapor permeability rate, cell viability, antioxidant and antibacterial activity were evaluated. By using Korsmeyer-Peppas and Higuchi kinetic models, the chry release mechanism in all nanofibers was studied in PBS solution, which suggested a Fick's diffusion. In-vitro antioxidant experiments by DPPH assay indicated 24, 43, 61 and 78 % free radical scavenging activity for PCL-CTS, PCL-CTS5, PCL-CTS10 and PCL-CTS15. In-vitro antibacterial examination showed that chry-loaded nanofibers had high antibacterial activity in which were comparable with the standard reagents. In-vitro cytotoxicity results obtained by MTT assay indicated a desired cytocompatibility towards fibroblast cells.

Control of mechanical and hydrophobic properties of silylated chitosan-starch films by cross-linking using carboxylic acids

We prepared polysaccharide films from silylated chitosan cross-linked with starch using six kinds of carboxylic acids (oxalic, maleic, citric, succinic, azelaic and sebacic acids) to explore the effects of molecular structures of cross-linkers on the mechanical, hydrophobic and water vapor permeability properties of these hydrophobicity-enhanced films. The films were analyzed by FT-IR, SEM, mechanical tests (stress versus strain, tensile strength and elongation at break curves) as well as the measurements of water contact angle, water solubility and water vapor permeability rate. We observed that the cross-linkers with a long chain provide a large mechanical strength; the tensile strength increases from 6 to 27 MPa with the chain length of dicarboxylates. The hydrophobicity, evaluated by the contact angle (ranging 80° ∼ 120°), increased with the chain length of the cross-linkers and was correlated well with the decreases of the solubility (94 ∼ 17%) and vapor permeability rate of water (14.5 ∼ 1.5 × 10−12 g s−1 m−1 Pa−1). We demonstrate that these mechanical, hydrophobic and water permeability properties are varied considerably only by the choice of the cross-linking acid also in the hydrophobicity-enhanced film by pre-silylation, which may widen the range of potential applications of polysaccharide film such as food packaging.

Development of a breathable polymeric membrane and process optimization by using a general full factorial design

The aim of this research was to produce a breathable hydrophilic membrane that can be laminated to textile fabrics to enhance their resistance to water penetration without restricting their breathability. For this purpose, aliphatic polyester polyurethane and acrylic ester copolymers were used. Quantities of both chemicals were varied according to three levels each. A general full factorial design was used to analyze responses that were the water vapor permeability index (WVPI (%)) and the absorption rate (Abs rate (%)). The membrane synthesis process was then optimized by using the Minitab response optimizer. The optimum polymeric membrane water vapor permeability and absorption rate were equal to 504.148 g?m-2?day-1 and 50.401%, respectively. Based on obtained results, the developed polymeric membrane was judged breathable. The morphological aspect of the dense membrane was also analyzed. It was noticed that air bubbles with different morphological types appeared in the nonporous membrane structure. Finally, it was concluded that the developed membrane can be thermo-assembled with other textile layers to enhance their resistance to wind and water penetration without affecting their breathability.

Physicochemical properties and pork preservation effects of lotus seed drill core powder starch-based active packaging films

Lotus seed drill core powder starch (LCPS)-based active packaging films incorporated with cellulose nanocrystals (CNC) and grapefruit essential oil-corn nanostarch Pickering emulsion (ECPE) were characterized, and their pork preservation effects were investigated in this study. In contrast with corn, potato and rice starches, LCPS showed higher amylose content, elliptical and circular shape with more uniform size distribution. Furthermore, LCPS film exhibited lower light transmittance, stronger tensile strength, and smaller elongation at break compared to the other starch films. Then, the LCPS film containing 4 % CNC and 9 % ECPE was fabricated which had stronger mechanical properties, lower water vapor permeability and oxygen transmission rate, and denser network structure. FTIR and XRD analyses also confirmed that CNC and ECPE were successfully implanted into the LCPS matrix without damaging the crystalline structure of LCPS. Herein, the LCPS/CNC/ECPE film exerted potential antibacterial activity against Escherichia coli and Staphylococcus aureus. Besides, packaging with this composite film significantly preserved the pork during cold storage via decreasing its juice loss rate, pH value, total number of colonies, total volatile base nitrogen and thiobarbituric acid reactive substance values. The present study will provide a theoretical basis for the application of LCPS as new biodegradable active films.

Evaluating Gelatin-Based Films with Graphene Nanoparticles for Wound Healing Applications

In this study, gelatin-based films containing graphene nanoparticles were obtained. Nanoparticles were taken from four chosen commercial graphene nanoplatelets with different surface areas, such as 150 m2/g, 300 m2/g, 500 m2/g, and 750 m2/g, obtained in different conditions. Their morphology was observed using SEM with STEM mode; porosity, Raman spectra and elemental analysis were checked; and biological properties, such as hemolysis and cytotoxicity, were evaluated. Then, the selected biocompatible nanoparticles were used as the gelatin film modification with 10% concentration. As a result of solvent evaporation, homogeneous thin films were obtained. The surface’s properties, mechanical strength, antioxidant activity, and water vapor permeation rate were examined to select the appropriate film for biomedical applications. We found that the addition of graphene nanoplatelets had a significant effect on the properties of materials, improving surface roughness, surface free energy, antioxidant activity, tensile strength, and Young’s modulus. For the most favorable candidate for wound dressing applications, we chose a gelatin film containing nanoparticles with a surface area of 500 m2/g.

Hyaluronic acid/tannic acid films for wound healing application

In this study, thin films based on hyaluronic acid (HA) with tannic acid (TA) were investigated in three different weight ratios (80HA/20TA, 50HA/50TA, 20HA/80TA) for their application as materials for wound healing. Surface free energy, as well as their roughness, mechanical properties, water vapor permeability rate, and antioxidant activity were determined. Moreover, their compatibility with blood and osteoblast cells was investigated. The irritation effect caused by hyaluronic acid/tannic acid films was also considered with the use of are constructed human epidermis model. The irritation effect for hyaluronic acid/tannic acid films by the in vitro method was also studied. The low surface free energy, surface roughness, and antioxidant activity presented by the obtained films were examined. All the tested compositions of hyaluronic acid/tannic acid films were hemocompatible, but only films based on 50HA/50TA were fully cytocompatible. Regarding the potential implantation, all the films except 80HA/20TA showed appropriate mechanical properties. The specimens did not exert the irritation effect during the studies involving reconstructed human epidermis.

POTENTIAL USE OF AN EDIBLE CANDELILLA WAX-BASED COATING TO EXTEND THE SHELF LIFE OF PASSION FRUIT

Passion fruit (Passiflora edulis f. flavicarpa Degener) is not widely traded due to its short shelf life. Edible coatings can be used to extend the postharvest life of fruits. The objective of this study was to develop a candelilla wax-based coating (Euphorbia antisyphilitica Zucc) for the preservation of passion fruit. Three coating formulations (C1, C2, and C3) were made with pectin, glycerol, and candelilla wax and applied by immersion. Weight loss and changes in physical appearance were used to assess shelf life under two storage conditions: room temperature (32 °C/6 days) and refrigeration (6.6 °C/32 days). Uncoated fruit in both storage conditions served as controls. Furthermore, a physicochemical characterization of the coatings was performed. Coated fruit at room temperature showed an improvement in weight retention compared to controls, but no differences in physical appearance were observed. In fruits stored under refrigeration, only C2 had less weight loss compared to the control, while C3 maintained a better physical appearance. In terms of coating characterization, C3 presented the lowest moisture content and thickness. C1 obtained the highest density value, while C1 also had the highest water vapor permeability rate (TPVA) value. The application of the C2 coating was effective in preserving the fruit for a longer period of time, and this coating has the lowest TPVA value, which is related to the decrease in weight loss in the fruit.

Antiseptic Chitosan-Poly(hexamethylene) Biguanide Hydrogel for the Treatment of Infectious Wounds.

Topical wound infections create the ideal conditions for microbial colonization and growth in terms of moisture, temperature, and nutrients. When they are not protected, numerous types of bacteria from the internal microbiota and the external environment may colonize them, creating a polymicrobial population. Treatment of these wounds often necessitates the use of antibiotics that may have systemic harmful effects. Unlike antibiotics, topical antiseptics exhibit a wider range of activity and reduced systemic toxicity and resistance. In order to address this issue, we developed an antiseptic Chitosan-Poly (hexamethylene) Biguanide (CS-PHMB) hydrogel. The prepared hydrogel was characterized using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). SEM images showed the smooth morphology and characteristic FTIR peaks of PHMB and confirmed the incorporation of the antiseptic into the chitosan (CS) hydrogel. A Water Vapor Permeation Rate study confirms the moisture retention ability of the CS-PHMB hydrogel. Rheological studies proved the gel strength and temperature stability. The prepared hydrogel inhibited the growth of S. aureus, P. aeruginosa, E. coli, methicillin-resistant Staphylococcus aureus (MRSA), and K. pneumoniae, which confirms its antibacterial properties. It also inhibited biofilm formation for S. aureus and E. coli. CS-PHMB hydrogel is also found to be hemo- and cytocompatible in nature. Thus, the developed CS-PHMB hydrogel is a very potent candidate to be used for treating infectious topical wounds with low systemic toxicity.

Intelligent double-layer polymers based on carboxymethyl cellulose-cellulose nanocrystals film and poly(lactic acid)-Viola odorata petal anthocyanins nanofibers to monitor food freshness

The present study was conducted with the aim of fabricating smart bilayer polymers based on carboxymethyl cellulose-cellulose nanocrystals film and poly(lactic acid)-Viola odorata extract nanofibers (CMC-CNC and PLA-VOE) for freshness monitoring of Pacific white shrimps, minced lamb meat, chicken fillets, and rainbow trout fillets, during refrigerated storage conditions. The fabricated indicators based on CMC-PLA-VOE 5%, CMC-CNC 1%-PLA-VOE 5%, and CMC-CNC 3%-PLA-VOE 5% presented remarkable color changes in pH 1–12 buffer solutions, including red at pH 1–6, violet at pH 7–8, green at pH 9–10, and brown at pH 11–12. Significantly lower water vapor permeability and oxygen transmission rate of prepared polymers were found in comparison with the control groups (P < 0.05). Regarding the monitoring of food samples in real-time, the samples spoiled after 3 days, evidenced by total viable count, psychrotrophic bacterial count, total volatile basic nitrogen, and pH values of 7.17–7.54 log CFU/g, 5.68–6.23 log CFU/g, 25.14–28.12 mg N/100 g, and 7.10–7.66, respectively. Meanwhile, the noticeable color change of prepared indicators from white to violet (day 3) and finally dark violet (day 7) was observed, indicating a potential application in intelligent packaging for real-time control of the freshness of perishable food samples.

Use of antibacterial effective food packaging of crosslinked polyvinyl alcohol/sodium caseinate/silver nanoparticle composite films

AbstractIn this study, composite films were produced with the solution casting method from prepared solutions by adding 1%, 3%, 5%, and 7% silver nanoparticles (Ag NPs) to blends 60/40 (w/w) ratio of polyvinyl alcohol and sodium caseinate (NCS). Afterward, the films were crosslinked by dipped in a glutaraldehyde bath. This crosslinking method applied to the films did not cause any adverse effects on the surface views of the films. The occurred aldehyde groups confirmed crosslinking. The thermal stability increased with crosslinking and increasing Ag NPs amount. The 1% Ag NP added film showed the highest tensile strength compared with the crosslinked raw film. The lowest moisture content was observed in 5% and 7% AgNP‐added films. The used crosslinking method increased the crosslinking efficiency compared with the crosslinking method in solution, ensuring a decrease in the total soluble matter (TSM) amount of the films. In addition, the TSM value continued to decrease proportionally with the increasing amount of Ag NP compared with the raw crosslinked film. Through the lowest swelling rate, the 3% AgNP‐added film exhibited the highest crosslinking density. While the water vapor permeability rate of the crosslinked raw film increased, a proportional decrease was observed by increasing Ag NPs. The 7% Ag NP added film exhibited the best barrier property. All films showed antibacterial activity against Escherichia coli and Staphylococcus aureus. It is suggested that the produced composite films can be used as food packaging with an antibacterial effect.Highlights PVA/NCS/Ag NPs blended composite films were obtained. The composite films were crosslinked in the glutaraldehyde bath. The crosslinked films exhibited high antibacterial activity. Low water vapor permeability and low swelling behavior were observed on films. Crosslinked PVA/NCS/Ag NPs films were suggested to be used as food packaging.

Effect of hydroxypropyl-β-cyclodextrin and lecithin co-stabilized nanoemulsions on the konjac glucomannan/pullulan film

In this study, the various ratio of hydroxypropyl-β-cyclodextrin (HPCD) to lecithin (LEC) was 0:1, 0.5:1, 1:1, 1.5:1 and 2:1 (w/w) co-stabilized cinnamon essential oil (CEO) nanoemulsions were prepared. These nanoemulsions were successfully incorporated in the konjac glucomannan/pullulan polysaccharides-based film matrix. The composition of nanoemulsions and the effect of various nanoemulsions on rheological, mechanical, Water vapor permeability, optical, color, morphology properties, and CEO retention rate of the composite films were characterized. The results demonstrated that HPCD and LEC nanoemulsions had small particle size under 120 nm and high stability during 21 days storage, the incorporation of nanoemulsions reduced the viscosity of film-solution, transmittance, Water vapor permeability and mechanical properties of films, but an appropriate HPCD content 1:1 w/w of nanoemulsions could restored the mechanical properties of the films. Otherwise, 1:1 w/w of nanoemulsion film also exhibited a more compact and uniform structure, Furthermore, 2:1 w/w of nanoemulsion films with high retention rate of CEO, and the antioxidant and better antibacterial activities against E. coli and S. aureus. The nanoemulsion films utilized in this study also prolonged the shelf life of Agaricus bisporus mushrooms and cherries while maintaining their commercial value.

Polycaprolactone nanofiber-alginate hydrogel interpenetrated skin substitute for regulation of wound-substitute interface

The management of the interface between the wound microenvironment and the skin substitute (SSS) is fundamental to wound repair and is an important factor in the regeneration of damaged tissue. Current biomaterials result in unideal repair effect of defective tissue due to limited management of early wound exudate and inability to respond positively to endogenous growth factors. Based on a refined electrospinning process, polycaprolactone fiber - alginate hydrogel interpenetrated network scaffold and subsequent multifunctional modifications serving as SSS was developed. The SSS exhibits excellent water absorption, water vapor permeability rate > 6000 g/m2/day and stretching properties. The amino-terminated hyperbranched polyamide enables the scaffold with both rapid antibacterial and reactive oxygen scavenging properties. Furthermore, fibroblast cells can be proliferated in the scaffold by 3D infiltration (>100 μm). Thus, the scaffolds are expected to be ideal candidates for the repair of different defective skin, especially those with excessive exudate.

Correlation between chain structures of corn starch and properties of its film prepared at different degrees of disorganization

This study investigated the relationship between the chain structure of corn starch and the properties of corn starch-based films formed with starch pastes with different degrees of disorganization (70, 80, and 90 °C). The degree of gelatinization, chain length distribution, amylose content, and molecular weight of the corn starch were determined by the water absorption index, ion chromatography, spectrophotometry, and gel chromatography, respectively. The thickness, surface roughness, solubility, water content, water vapor permeability, mechanical properties, and maximum thermal degradation rate of corn starch-based films formed with starch pastes with different degrees of disorganization were evaluated. The moisture content, thickness and surface roughness of films formed with the starch pastes decreased. At the same time, the solubility, elongation at break, water vapor permeability, and molecular weight distribution increased with increasing heat treatment temperature. The maximum thermal degradation rate and tensile strength of the corn starch-based films formed with the starch pastes decreased with increasing heat treatment temperature. The gradual decrease in the amylose content of corn starch-based films formed with starch paste with increasing heat treatment temperature led to a change in the performance of the corn starch-based films.

Improvement of the barrier and mechanical properties of environmentally friendly mango kernel flour/glycerol films by varying the particle size of mango kernel flour

The development of environmentally friendly films based on glycerol and different sizes of mango kernel flour particles (MKF), ranging from 100 to 600 µm, is reported. The casting solution method was used to produce the films, using distilled water as the solvent. The mechanical, morphological, barrier, surface, optical, wettability and biodegradability properties of the films were assessed. The mechanical analysis revealed that smaller particles lead to superior mechanical performance in terms of tensile strength, elastic modulus and elongation at break, achieving an elongation at break of 18.1 % for the films with the smallest particle size (100 µm). These results were confirmed by field emission scanning electron microscopy (FESEM) images of the films, where the gap between the mango kernel particles and the glycerol matrix is practically non-existent in films with the smallest particle size (100 µm). On the other hand, it was observed that as the particle size decreased, the barrier properties improved, showing a decrease in water vapor permeability rate (WVPR). With respect to antioxidant properties, it was observed that the films showed strong antioxidant activity, as assessed by 2,2–diphenyl–1–picrylhydrazyl (DPPH) inhibition above 90 % for all films after 1 week. Finally, MKF films proved to be completely biodegradable, with a 100 % of disintegration after 4 weeks of incubation time in compost soil, with the smallest MKF particle size films exhibiting the highest disintegration rate. • Smaller MKF particle size in the films leads to superior mechanical, barrier, antioxidant and biodegradability properties. • MKF/glycerol films possess strong antioxidant capabilities based on DPPH inhibition tests. • MKF/glycerol films present complete disintegration at 21 days of incubation in compost soil.