Water Vapor Permeability Research Articles

Comparison of Polylactide-Based Active Films Containing Berberine and Quercetin as Systems for Maintaining the Quality and Safety of Blueberries.

Polymeric thin films based on polylactide with an addition of poly(ethylene glycol) as a plasticizer and flavonoids in the form of quercetin and berberine were subjected to tests that were particularly relevant from the point of view of contact with food. A comparative analysis of the effect of individual flavonoids on the antioxidative properties of tested films and blueberry storage was carried out. The influence of active compounds on the water vapor permeability, as well as UV protection, of the obtained materials was investigated. Also, the specific migration of individual flavonoids from obtained materials to food simulants in the form of acetic acid and ethyl alcohol was determined. The crucial point of this study is the storage of blueberries. The obtained results indicate that the selection of packaging, containing individual active compounds, depends on the purpose and requirements that the packaging must meet for particular types of food.

Active Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) Films Containing Phenolic Compounds with Different Molecular Structures.

To obtain more sustainable and active food packaging materials, PHBV films containing 5% wt. of phenolic compounds with different molecular structures (ferulic acid, vanillin, and catechin) and proved antioxidant and antimicrobial properties were obtained by melt blending and compression molding. These were characterized by their structural, mechanical, barrier, and optical properties, as well as the polymer crystallization, thermal stability, and component migration in different food simulants. Phenolic compounds were homogenously integrated within the polymer matrix, affecting the film properties differently. Ferulic acid, and mainly catechin, had an anti-plasticizing effect (increasing the polymer glass transition temperature), decreasing the film extensibility and the resistance to breaking, with slight changes in the elastic modulus. In contrast, vanillin provoked a plasticizing effect, decreasing the elastic modulus without notable changes in the film extensibility while increasing the water vapor permeability. All phenolic compounds, mainly catechin, improved the oxygen barrier capacity of PHBV films and interfered with the polymer crystallization, reducing the melting point and crystallinity degree. The thermal stability of the material was little affected by the incorporation of phenols. The migration of passive components of the different PHBV films was lower than the overall migration limit in every simulant. Phenolic compounds were released to a different extent depending on their thermo-sensitivity, which affected their final content in the film, their bonding forces in the polymer matrix, and the simulant polarity. Their effective release in real foods will determine their active action for food preservation. Catechin was the best preserved, while ferulic acid was the most released.

Characterization of Biodegradable Films from Raw Seaweed (Kappaphycus Alvarezii) and Glycerol

Abstract To reduce the use of plastic, innovation is needed to make packaging materials that are environmentally friendly and easy to be degraded. As the main ingredient of this packaging material should be organic materials that are easily obtained. One of the organic materials is seaweed (Kappaphycus Alvarezii) which can be used as raw material for making biodegradable packaging and combined with glycerol. Biodegradable films with nine combinations of seaweed and glycerol were developed to gain the best composition. The yields of these combinations were tested on their tensile strength, elongation, Modulus Young, Water Vapor Permeability, and biodegradability. The Tensile Strength value of the film with 1 gram seaweed and 1 gram glycerol (S1G1) was the highest (22.366±2.148017 MPa), The elongations values of the films with 1.5 g glycerol and 2 g seaweed (18.99217±2.442663%) were highest significantly. The water vapor permeability (WVP) and the thickness of the composite films increased due to the increase of seaweed and glycerol amounts respectively. The biodegradability increased if the seaweed amounts decreased, but it increased if the glycerol amounts increased as well.

Carrageenan-based functional films hybridized with carbon dots and anthocyanins from rose petals for smart food packaging applications

Multifunctional smart biopolymeric films were fabricated using rose petal anthocyanin (RPA) and carrageenan (CAR) doped with rose petal-derived carbon dots (RP-CDs). Response surface-optimized RPA showed the highest total anthocyanins and radical scavenging ability. Produced RP-CD exhibited UV absorption and high fluorescence with antibacterial/antioxidant abilities. Enrichment with 2 % RP-CD and 5 % RPA in the CAR matrix results in improved physicochemical, i.e., water contact angle, water vapor permeability, and UV-blocking properties of the fabricated material. Results showed that nanocomposite films scavenged radicals better than the neat CAR films. Zeta potential, FTIR, SEM, and XPS suggested improved compatibility/stability and enhanced elemental configuration of RP-CDs/RPA additives in the CAR polymer matrix. Perishable food packaging (minced pork and shrimp) demonstrated that nanocomposite films work efficiently and non-destructively and are promising tools for monitoring real-time freshness through interpretable visual changes from red to yellow. The CAR/RP-CDs/RPA-based nanocomposite indicator films are expected to be applied as various smart packaging materials. These films possess the ability to promptly detect changes in quality, preserve the quality, and prolong the shelf life of packaged foods.

The preparation of edible water-soluble films comprising κ-carrageenan/carboxymethyl starch/gum ghatti and their application in instant coffee powder packaging

This study successfully prepared an edible packaging film that rapidly dissolves in water by utilizing a combination of κ-carrageenan, carboxymethyl starch, and gum ghatti. We investigated the influence of these three materials on the microstructure and physical properties of the film, as well as the impact of the film's dissolution on the stability of beverages. SEM, FTIR, and XRD analyses revealed that the κ-carrageenan, carboxymethyl starch, and gum ghatti primarily interacted through hydrogen bonding, resulting in a more uniform and dense film structure. Surface hydrophilicity and swelling tests indicated an increased presence of hydrophilic groups in the composite film. The inclusion of carboxymethyl starch and gum ghatti significantly improves the film's physical properties, resulting in a notable reduction in water solubility time, an increase in elongation at break from 19.5 % to 26.0 %, a rise in the contact angle from 49.1° to 67.0°, and a decrease in water vapor permeability from 7.5 × 10–10 to 6.2 × 10–10 g/m·s·Pa. Furthermore, coffee packaging bags made from this composite film dissolved entirely in hot water in just 40 s. Dissolving these bags significantly improved the stability of instant coffee, reducing centrifugal sedimentation from 3.8 % to 1.7 %. This study highlights the substantial potential of the κ-carrageenan/carboxymethyl starch/gum ghatti composite film as a packaging material for solid beverages.

Unveiling the swelling behavior of κ-carrageenan hydrogels: Influence of composition and physiological environment on drug delivery potential

This study aims to develop a biodegradable hydrogel wound dressing film based on carrageenan and agar loaded with tetracycline (TC), which exhibits high antibacterial properties and accelerates wound healing. The swelling behavior of κ-carrageenan/agar and tetracycline-loaded hydrogel films was examined, with a focus on the hydrogel’s efficacy in various physiological fluids, as well as the effects of polysaccharide ratio, cross-linker concentration, and surfactant concentration. The results revealed that the polysaccharide ratio significantly influenced the hydrogel swelling capacity of hydrogel, and a 1:1 ratio of agar to κ-carrageenan achieved the highest swelling degree of 1386 %. Addition of KCl, as a cross-linker, increased swelling capacity to 1713 %. Furthermore, surfactant concentration also influenced swelling behavior, and higher concentrations resulted in an increase in hydrophilicity and swelling. Hydrogel swelling performance varied across physiological fluids, with the highest and lowest swellings observed in deionized water (DIW) and simulated wound fluid (SWF), respectively. The swelling process in DIW and phosphate buffered saline (PBS) exhibited second-order kinetics, whereas non-Fickian diffusion mechanisms were observed in SWF. The drug release of the κC/AG/TC hydrogel film was controlled by its swelling capacity and the pH of medium. The hydrogels’ mechanical properties, antibacterial activity, and water vapor permeability were also investigated.

Development and characterization of cellulose‐based smart films extracted from coconut waste

AbstractThe increasing demands for safe and quality packaged food have diverted all the intentions toward the enhancement of hazard detection and quantification techniques. The integration of smart functions with the novel biomaterials‐based packaging provides an effective approach to deal with the uplifting concerns of food safety and environmental pollution. In the current study, firstly the cellulose was extracted from coconut waste, then it was subjected to prepare biodegradable films and lastly the films were incorporated with curcumin or quercetin dihydrate. The films were characterized for their mechanical, barrier and smart properties. The incorporation of curcumin or quercetin dihydrate improved the physicochemical properties of the cellulose films, including strength, elongation at break (EAB), water vapor permeability (WVP), biodegradability, antioxidant and antimicrobial activity. However, the moisture content and water solubility decreased. The scanning electron microscopy (SEM) images depicted the rough surface of curcumin incorporated smart films which represents successful application of curcumin, while cracks and pits were observed for the films with the higher concentration of quercetin dihydrate. All the smart films showed effective responses against pH ranging from 2 to 14.

Preparation and property analysis of extruded blown Guar gum based PBAT/PLA composite film: Approach towards sustainable packaging

The study on sustainable packaging led to the development of numerous compostable polymer components for ecofriendly packaging applications. As a promising biodegradable packaging material, this study was done to evaluate the manufacture and characteristics of Guar gum/PLA/PBAT composite films via two-step extrusion procedure, Guar gum, polylactic acid (PLA), and polybutylene adipate terephthalate (PBAT) were used as the matrix ingredients to create the composite films. The impact of Guar gum content on the composite films were assessed with the help of physical, mechanical, and barrier characteristics. The findings demonstrated that with incorporation of Guar gum in the composite film increases the tensile strength upto 153.06 % while preserving their biodegradability behaviour. The developed composite films exhibit good hydrophobicity as shown by contact angle of 89.55° also decrease in water vapour permeability 26.49 gm/m2 when PLA content was increased. The composite films also demonstrated improved thermal stability up to 200 °C. The current study suggest that Guar gum/PBAT/PLA composite films have intact its compostability with enhanced mechanical and barrier qualities giving an opportunity to substitute conventional petroleum-based plastic packaging.

Study on poly(butylene adipate‐co‐terephthalate)/thermoplastic starch/poly((R)‐3‐hydroxybutyrate‐co‐(R)‐3‐hydroxyhexanoate) biodegradable films with enhanced gas barrier properties

AbstractBioplastic films with excellent barrier properties were successfully prepared from poly(butylene adipate‐co‐terephthalate) (PBAT), thermoplastic starch (TPS), and poly((R)‐3‐hydroxybutyrate‐co‐(R)‐3‐hydroxyhexanoate) (PHBHHx). The rheological, mechanical, barrier, dynamic mechanical properties, and microstructure of the PBAT/TPS/PHBHHx films were studied. The transition of the continuous phase in the blend significantly affects the properties of the films. The increase in PHBHHx content results in its transition from a dispersed phase to a continuous phase. This phase transition, along with the consequent increase in the crystallinity of PHBHHx, greatly enhances the barrier properties of the film. The percentage crystalline degree of PHBHHx increased from 10.9% to 25.1% with increasing PHBHHx content from 0% to 50%. The film containing 50% PHBHHx showed a significant decrease in both water vapor permeability (WVP) and oxygen permeability (OP) by 75.1% and 69.6%, respectively. It found that the film containing 50% PHBHHx exhibited a decrease of elongation at break from 505% to less than 10% but an unusual increase of tensile strength after a 72‐hour aging test, which is different from PBAT and PBAT/TPS films. However, this indicates that the extensibility of PHBHHx is more susceptible to the effects of aging test, leading to the rearrangement of polymer chains from disordered to ordered morphology.

Effect of improved electric field distribution on jet motion, fiber morphology, and properties of electrospun thermoplastic polyurethane fibrous membrane

AbstractElectric field plays a pivotal role in electrospinning to produce the desired micro and nanofibers, hence, a tricipital‐needle spinneret was developed to improve electric field distribution and productivity in this work. The effects of electric field distribution induced by spinneret configuration on jet motion, fiber morphology, and properties of electrospun TPU fibrous membrane at different applied voltages were investigated by simulation and experiment. The simulation results show that the designed tricipital‐needle spinneret weakens the electric field near the needle tip and strengthens the electric field in the whipping region in comparison to the single‐needle spinneret, exhibiting a relatively uniform electric field distribution. The experimental results demonstrate that the fiber diameter prepared by the tricipital‐needle spinneret at the corresponding voltage is smaller than that of the single‐needle spinneret due to the improved electric field distribution. Moreover, the fibrous membrane prepared by the tricipital‐needle spinneret shows excellent tensile properties (7 MPa tensile stress and 401% breaking elongation), air permeability (85.32 mm s−1) and water vapor permeability (6.7 kg m−2 d−1). Therefore, the electrospinning system with the tricipital‐needle spinneret not only increases the fiber productivity, but also improves the electric field distribution and endows the fibrous membrane with better properties, which can widen the applications of electrospun TPU fibrous membrane and also provides a new approach for the performance design of other electrospun fibers.

Innovative edible film for fresh fruit packaging: Formulation and characterization

Edible packaging films are gaining attention as an innovative and sustainable solution for food preservation, providing a protective barrier against physical damage, microbial contamination, and environmental factors. This study aimed to develop an advanced edible packaging film by incorporating galactooligosaccharides (GOS) to strengthen intermolecular interactions and improve film integrity. The composite film, consisting of chitosan (CS), zein, and GOS, was carefully optimized and thoroughly characterized for its physicochemical properties. The impact of GOS incorporation on the film's mechanical strength, barrier properties, and performance in food preservation was systematically investigated. The resulting CS-Zein-GOS film, fabricated with a 1 % (w/v) concentration using the solvent casting technique, exhibited enhanced light-blocking capabilities, improved hydrophobicity, and significantly improved barrier properties against water vapor and oxygen permeability compared to the CS counterpart. Moreover, the composite film displayed thermal stability up to 303.91 °C and superior flexibility, as indicated by elongation at break and tensile strength values. Application tests showed that the CS-Zein-GOS coating effectively extended the shelf life of strawberries and cherries at room temperature by up to three days. Analytical techniques revealed the interaction between the components and confirmed the potential of this novel water-soluble, edible film in food packaging applications, particularly for fresh produce, to extend shelf life and reduce plastic waste. These findings highlight the promising prospects of edible packaging films in addressing sustainability challenges in the food industry.

Caffeic Acid Encapsulated Centrifugally Spun Antioxidant Fibers: Characterization and Incorporation in Cakes

AbstractThe primary aim of this study was to formulate a cake with high antioxidant activity through the incorporation of centrifugally spun gelatin-based fiber which was enriched with caffeic acid. Characterization analyses were conducted to evaluate fibers with different concentrations of caffeic acid (2% and 4%), while simultaneously the effects of thermal and citric acid crosslinking on the physical and functional properties of the encapsulated fibers were investigated. The study revealed varying encapsulation efficiencies of caffeic acid in gelatin fibers (56.34–94.55%), markedly affected by substantial reduction of thermal crosslinking, contrasting with citric acid’s minimal impact. Additionally, citric acid increased total phenolic content (TPC), but thermal treatment notably decreased antioxidant activity (AOA) due to its impact on radical scavenging and phenolic group dissociation. The addition of citric acid significantly reduced water vapor permeability by 22% suggesting an induced crosslinking in both thermal-treated caffeic acid and citric acid samples. The study highlighted reduced AOA and phenolic content in thermally treated fibers (thermally treated gelatin with 2% caffeic acid vs thermally treated gelatin with 4% caffeic acid), suggesting lower water solubility and improved thermal stability with approximately 24% remaining weight after thermogravimetric analysis. Despite this, cakes with thermally treated fibers had higher AOA due to improved heat resistance of fibers. Generally, adding fibers to cakes decreased hardness and pH while increasing TPC, AOA, and volume index, showing a novel approach using centrifugally spun fibers to enrich foods with antioxidants.

Improving the antioxidant ability of gelatin-chitosan film by incorporating an oil-in-water (O/W) Pickering emulsion emulsified by betanin-loaded quaternary ammonium-functionalized mesoporous silica nanoparticles

Active food packaging films with biological activities are a promising food technology, and antioxidant ability is one of the most important biological activities. In this study, an antioxidant active packaging film was prepared by directly blending gelatin, chitosan and a novel O/W Pickering emulsion and then drying. The emulsion was prepared from two antioxidant compounds, Mesona Chinensis essential oils (MCB-EO) and betanin-loaded quaternary ammonium-functionalized mesoporous silica nanoparticles (betanin-QAMSNPs), which provide this emulsion with high antioxidant activity. After adding the emulsion, the water content (26.63 %), water solubility (28.3 %), and water contact angle (86.2°) of the film are lower than those of the gelatin-chitosan film. The thickness and water vapour permeabilities of the betanin-Pickering emulsion film are 275.25 µm and 4.802 × 10−10 g·s−1·m−1·Pa−1, respectively, which are higher than those of gelatin-chitosan films. Adding betanin-Pickering emulsions can decrease the roughness of the surface, which is observed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The DPPH and ABTs+ free radical scavenging capacities of the betanin-Pickering emulsion films are 21.77 % and 91.87 %, respectively, which are higher than those of the gelatin-chitosan films (4.64 % and 61.15 %), indicating that adding the betanin-Pickering emulsion can enhance the antioxidant ability of the gelatin-chitosan films. The betanin-Pickering emulsion films can inhibit the oxidation of soybean oil. In conclusion, in this study, a novel food packaging film was successfully prepared and has potential application as an antioxidant food packaging material.

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.

Investigation of polypropylene yarns containing silver nanoparticles: Fiber characteristics, yarn properties, and fabric performance analysis

AbstractThis study focuses on the development of antimicrobial technical textiles using silver‐infused polypropylene fibers to meet the escalating demand for enhanced protection against pathogens in medical settings. Various polypropylene‐based fibers with different silver concentrations and cross‐sections were produced through spinning experiments, resulting in six distinct fiber types. Comprehensive analyses, including differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X‐Ray diffraction (XRD), were conducted to evaluate thermal and structural properties. Physical strength and morphological characteristics were examined to determine optimal compositions. Subsequently, selected fibers were spun into yarns and knitted to create textile surfaces. Evaluation encompassed physical attributes, color, morphology, water vapor permeability, and antimicrobial efficacy against Gram‐negative bacteria, particularly E.coli. The results demonstrated over 99% antibacterial activity across all samples, highlighting their potential utility in medical textiles and other applications. Additionally, the study revealed that the water vapor permeability values were higher in fabric samples without silver nanoparticle additives, with a negligible decrease observed in samples with higher silver nanoparticle concentrations. The antibacterial activity was found to increase with higher silver concentrations in trilobal cross‐section samples. Round cross‐section samples exhibited higher antibacterial activity at the same silver concentration. These findings provide valuable insights for future antibacterial‐based fiber production studies and literature.

Nanohybrids with potential barrier property and antimicrobial activity for application in sustainable polymer food packaging: A mini‐review

AbstractPackaging has important functions for products, contributing to their protection and presenting information. Recognizing that food loss and waste affect all countries, it is necessary to search for alternatives that change this scenario, such as active packaging. Particles with sizes between 1 and 100 nanometers (nanoparticles) are incorporated into polymeric materials because they are capable of improving or even providing properties that the film formed by the pure polymer does not have, due to its surface area being greater than that of macro‐sized particles. If two nanoparticles are previously combined to form a nanohybrid before being dispersed in a polymeric matrix, in addition to having this purpose, they can provide even better results when incorporated, due to the synergistic effects that can be attributed to the nanoparticles used. The utilization of active packaging composed of nano‐hybrids within biodegradable polymers holds significant potential for reducing solid plastic waste and the generation of persistent microplastics, thereby positively impacting human health. In this literature review, the effects of nanohybrid on antibacterial and barrier properties for application in food packaging in polymeric matrices were investigated using materials such as: nickel nanoparticles, zinc oxide nanoparticles, silver nanoparticles, copper oxide nanoparticles, cellulose nanowhiskers, Cloisite 30B, sodium alginate, poly(ethylene oxide), starch, poly(vinyl alcohol), chitosan and gelatin. The results were found to show the efficiency of nanohybrids in polymeric matrices, decreasing the water vapor and oxygen permeability and also increasing the antibacterial activity, which can prevent illnesses stemming from contaminated food occurs.

Augmenting barrier efficiency in clay‐based starch composite films for enhanced packaging sustainability

AbstractThe pervasive utilization of plastic as a cost‐effective packaging material for food has led to environmental concerns, primarily due to its non‐biodegradable nature and the ensuing release of carbon dioxide gas that contributes to global warming. In response to these challenges, researchers have shifted their focus toward biopolymers to develop eco‐friendly packaging solutions. The present study introduces a novel approach to study the release of micronutrient (Fe) from clay free starch‐glycerol film and clay‐starch‐glycerol composite film. The structural composition and characteristics of the synthesized film are meticulously examined using x‐ray diffraction (XRD), ATR, scanning electron microscopy and transmission electron microscopy analytical techniques. Notably, XRD analysis reveals a significant interaction between the starch chains and Mt through hydrogen bonding, indicative of starch and glycerol intercalation within the nanoclay gallery—a phenomenon further corroborated by IR spectra analysis. The nanoclay‐infused starch/glycerol composite film exhibits a noteworthy 2.22‐fold increase in water vapor permeability compared to clay free film, attributed to the formation of a convoluted diffusion path indicating the enhancement of the barrier performance of starch‐based films. Comparative evaluations against earlier studies are undertaken to elucidate the advancements in barrier properties, subsequently elucidating the underlying mechanisms through analytical interpretations. From the release study, the release of Fe2+ from the film with clay was observed to be more prolonged compared to a film without clay. As a result, the Montmorillonite clay–polymer composite film was selected for coating rice seeds using the dip‐coating method.

Preservation of chilled beef using active films based on bacterial cellulose and polyvinyl alcohol with the incorporation of Perilla essential oil Pickering emulsion

In this study, Perilla essential oil (PEO) Pickering emulsions, prepared using soybean protein isolate-chitosan nanoparticles (SPI-CSNPs) as emulsifiers (SCEO), were used to improve the performance of bacterial cellulose/polyvinyl alcohol (BC/PVA) films for application in chilled beef preservation. The SCEO has a smaller particle size (185 nm), higher viscosity, a more uniform dispersion and was more stable at an oil phase volume fraction of 80 %. An increase in the films' surface roughness and in the hydrogen bonding between SCEO and the films' matrix was also observed, resulting in a lower tensile strength (TS, 94.75–62.02 MPa) and higher elongation at break (EAB, 26.78–55.62 %). Moreover, the thermal stability, water vapor permeability, antioxidant and antibacterial properties of the composite films improved as the SCEO content increased. Furthermore, the Pickering emulsion method was effective in preventing the loss of PEO during storage. Overall, one particular composite film, BP/SCEO3, could prolong the shelf life of chilled beef by up to 14 days, and hence was promising for food preservation.

Physicochemical Properties of a Bioactive Polysaccharide Film from Cassia grandis with Immobilized Collagenase from Streptomyces parvulus (DPUA/1573)

(1) Background: Polysaccharide films are promising vehicles for the delivery of bioactive agents such as collagenases, as they provide controlled release at the wound site, facilitating tissue regeneration. This study aimed to investigate the physicochemical properties of Cassia grandis polysaccharide films with immobilized collagenase from Streptomyces parvulus (DPUA/1573). (2) Methods: Galactomannan was extracted from Cassia grandis seeds for film production with 0.8% (w/v) galactomannan and 0.2% (v/v) glycerol with or without collagenases. The films underwent physical-chemical analyses: Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), color and opacity (luminosity-L*, green to red-a*, yellow to blue-b*, opacity-Y%), moisture content, water vapor permeability (WVP), thickness, contact angle, and mechanical properties. (3) Results: The results showed similar FTIR spectra to the literature, indicating carbonyl functional groups. Immobilizing bioactive compounds increased surface roughness observed in SEM. TGA indicated a better viability for films with immobilized S. parvulus enzymes. Both collagenase-containing and control films exhibited a bright-yellowish color with slight opacity (Y%). Mechanical tests revealed decreased rigidity in PCF (−25%) and SCF (−41%) and increased deformability in films with the immobilized bioactive compounds, PCF (234%) and SCF (295%). (4) Conclusions: Polysaccharide-based films are promising biomaterials for controlled composition, biocompatibility, biodegradability, and wound healing, with a potential in pharmacological applications.

Utilization of Pickering emulsion stabilized by chitin nanofibers for improving water and oxygen resistance of gelatin films

The hydrophilicity of gelatin films obviously limits their application. In this work, novel protonated chitin nanofiber was prepared with green methods, surficial deacetylation combined with acidic and mechanical treatment. Composite films with excellent water and oxygen barrier properties were successfully prepared by blending O/W Pickering emulsions stabilized by chitin nanofibers with gelatin substrates. The films were characterized by Fourier-transform infrared, X-ray diffraction, mechanical properties, water and oxygen permeability, moisture content, water solubility, water contact angle and optical properties. The results demonstrated that the amino groups of chitin nanofibers bound to the carboxyl groups of gelatin via electrostatic interactions, which contributing to the excellent mechanical and barrier properties of composite films. The elongation at break of composite film (the concentration of chitin nanofiber was 0.2 wt%) was 2.66 times of gelatin film. And the water vapor and oxygen permeability of composite films lowered to 65.9 % and 52.9 %, respectively. The introduction of O/W Pickering emulsion significantly enhanced the hydrophobicity of gelatin-based film and the chitin nanofibers played a positive role in stabilizing the gelatin chains to a certain extent. This study expands the application fields of gelatin-based films and provides valuable technical route for the preparation of barrier films.