Gelatin Films Research Articles

Fabrication and Characterization of Intelligent Multi-Layered Biopolymer Film Incorporated with pH-Sensitive Red Cabbage Extract to Indicate Fish Freshness.

This study aimed to fabricate an intelligent monolayer and multi-layered biodegradable films incorporated with red cabbage extract (RCE) to act as a safe and reliable freshness indicator. A film-forming solution (FFS) of gelatin, carboxymethyl cellulose (CMC) and chitosan was prepared and fortified with 0.5% (w/v) of RCE for developing intelligent monolayer films. The intelligent multi-layer film was prepared via layer by layer casting of gelatin, chitosan (added with 0.5% of RCE) and CMC biopolymers. The thickness of the multi-layered film was the highest (0.123 ± 0.001 mm) compared to gelatin-, CMC- and chitosan-based monolayer films (p < 0.05). Chitosan film has the highest tensile strength (p < 0.05), followed by multi-layer, CMC and gelatin films. Elongation at break was slightly higher in CMC (35.67 ± 7.62%) compared to the multi-layer film (33.12 ± 9.88%) and gelatin film (p > 0.05). Water vapor permeability was higher in the multi-layer film (1.244 ± 0.05 × 10-5 g mm h-1cm-2 P-1) than the other monolayer films. Moisture content was highest in chitosan film followed by the multi-layered film (p < 0.05) and then the CMC and gelatin films. CMC film showed the highest solubility compared to multi-layered and chitosan film (p < 0.05). Additionally, transmittance and transparency values in the multi-layered film were the lowest compared to the chitosan-, CMC- and gelatin-based films. L* and a* values were the lowest, while b* values increased in the multi-layered film compared to the other film samples (p < 0.05). pH sensitivity and ammonia gas tests revealed similar color changes in chitosan and multi-layer films. However, FTIR spectra confirmed that dye leaching was not detected for the multi-layered film soaked in ethanol. The biodegradability test showed rapid degradation of multi-layered and chitosan films within 1 month. Based on the optimum results of the multi-layered film, it was applied to monitor the fresh quality of tilapia fish fillets at 4 °C for 10 days. The results of freshness acceptability were noted on day 6 due to the change in color of the multi-layer film with an estimated total volatile basic nitrogen content of 21.23 mg/100 g. Thus, the multi-layered film can be used as an indicator to monitor the quality of the fish freshness without leaching dye onto the food surface.

Multifunctional film based on gelatin with titanium dioxide and thymol@β-cyclodextrins for fresh-keeping packaging

Microbial infection and ethylene accumulation can cause spoilage of fresh fruit and vegetables during postharvest storage. Here, gelatin film incorporated with titanium dioxide (TiO2) nanoparticles and thymol-loaded β-cyclodextrin (THY@β-CD) was prepared by the solution casting method for scavenging ethylene and inhibiting microbial growth. The scanning electron microscope and ethylene scavenging experiment showed that 1% TiO2 nanoparticles did not agglomerate in the gelatin film and achieved 23.1% ethylene degradation efficiency under UV light. Loading rate and thymol release behaviors indicated that thymol encapsulated in the β-CD carrier could be effectively loaded into gelatin film and avoid rapid volatilization. More importantly, TiO2 and thymol exhibited synergistic antimicrobial properties under UV light, achieving a 100% inhibition rate against Escherichia coli, Staphylococcus aureus, and Rhizopus stolonifer. In addition, the THY@β-CD/TiO2/Gel film had good tensile strength, water solubility, and biocompatibility. And they could significantly extend the shelf life of strawberries and tomatoes. Hence, this active packaging film system provided an effective postharvest strategy for delaying ripening and avoiding microbial contamination.

Properties enhancement of packaging materials based on gelatin

AbstractThe main disadvantages of plastic materials are that they do not readily break down in the environment and cause harmful effects. For a specific use, biodegradable and/or edible films have been produced to totally replace some typical polymeric packaging materials. Protein and polysaccharides biopolymers have film‐forming properties that are useful for food packaging. Gelatin is an example of a protein that has the ability to form a film, has strong functional qualities, and can be used as an exterior barrier to prevent drying. Gelatin has adverse effects on food packaging application, especially mechanical properties and water vapor permeability. The effect of the incorporation of plasticizers in gelatin films is reviewed and presented. The plasticizer can improve the extensibility, dispensability, flexibility, elasticity, and rigidity of biopolymers and biopolymers composites. The plasticizers reviewed are glycerol, sorbitol, lignin, root essential oils, bergamot oil, lemongrass oil, sucrose, oleic acid, malic acid, and citric acid, and others. These plasticizers have strengthened the film structure by continuity of polymer matrix where the gelatin films become more stretchable and also flexible. This study also discussed the effect of plasticizers on other properties of gelatin film such as water vapor permeability (WVP), thermal properties, water‐solubility, moisture content, oxygen permeability, light transmission, and transparency.

Extruded transglutaminase-modified gelatin–beeswax composite packaging film

Fish gelatin (FG) is a natural biodegradable biopolymer. However, solution casting, which is commonly used to prepare gelatin films, limits large-scale film production. In this study, melt extrusion (ME) commonly used in traditional plastics was successfully applied to the preparation of gelatin composite films. The non-covalent crosslinking between hydrophobic beeswax (BW) and hydrophilic FG not only reduced the film stickiness during rolling but also decreased the water solubility of the film by 45.17% ( p < 0.05). Transglutaminase (TGase) promoted covalent crosslinking between the FG networks, thereby improving the properties of the film. The results of Fourier transform infrared (FTIR) spectroscopy confirmed the crosslinking effect of BW and TGase on the gelatin films, and appropriate crosslinking maintained the forward movement of gelatin in the rotating screw according to a linear mode. The FG–BW–1%TGase film exhibited the lowest water solubility of 36.63% and the highest tensile strength of 6.26 MPa. The co-crosslinking of TGase and BW contributed to the preparation of melt-extruded composite films exhibiting desirable properties and were potential candidates for commercial food packaging. • Fish gelatin (FG) composite films were prepared using melt extrusion. • Beeswax (BW) and transglutaminase (TGase) were added to films. • BW reduced film stickiness during rolling. • TGase crosslinked FG networks, thereby improving film properties. • Composite films show excellent potential for application to food packaging.

Improved properties of gelatin films involving transglutaminase cross-linking and ethanol dehydration: The self-assembly role of chitosan and montmorillonite

In this study, the chitosan and montmorillonite (MMT) were synergistically introduced to improve the properties of the gelatin films through self-assembly. The preparation of gelatin films (G), gelatin + MMT composite films (G + MMT), gelatin-chitosan bilayer films (G-CS), and gelatin + MMT-chitosan composite bilayer films (G + MMT-CS) involved transglutaminase (TG) cross-linking followed by ethanol precipitation and self-assembly process. The water contact angle of the composite bilayer films (G-CS and G + MMT-CS) was higher than 110° due to the formation of surface hydrophobic layer formed by self-assembly via hydrogen bonding and electrostatic interaction between gelatin and chitosan, but the MMT alone cannot improve the hydrophobicity of gelatin films. The water solubility (WS) of G + MMT, G-CS and G + MMT-CS films was significantly lower than that of G films. The mechanical and barrier properties were significantly improved due to the introduction of MMT and the surface deposition of chitosan, attributing to the increase of triple helix content and formation of bilayer structure, respectively. Moreover, MMT caused the decrease of sterilization thermal shrinkage from 49.54% to 34.00%. Interestingly, MMT facilitated the surface deposition of chitosan during self-assembly process. The mold growth of bread wrapped with G + MMT-CS was effectively inhibited during storage, implying potential application as antimicrobial food packaging materials. • Self-assembly of gelatin and chitosan improved hydrophobicity of gelatin (G) films. • Chitosan and montmorillonite improved mechanical and barrier properties of G films. • Sterilization thermal shrinkage of G films was reduced by montmorillonite. • Introducing montmorillonite facilitated the self-assembly deposition of chitosan.

Green silver nanoparticles functionalised gelatin nanocomposite film for wound healing: Construction and characterization

Wound dressings have progressed from simple to advance by the interdisciplinary approaches of chemical, materials and biological fields to engineer the functional materials that can improve wound healing by reducing bacterial infections on wound site. In the present study, Praecitrullus fistulosus extract was used for the preparation of silver nanoparticles (Ag NPs) via a green synthesis method for wound healing. The synthesized Ag NPs were characterized via Ultraviolet–Visible (UV–Vis) spectroscopy, High-Resolution X-ray Diffractometer (HRXRD), and High-Resolution Transmission Electron Microscopy (HRTEM). The gelatin-Neem extract-nanocomposite films were prepared by incorporating green Ag NPs via solvent casting method. The physico-chemical, morphological, structural, thermal, and biological properties of the nanocomposite (NCP) films were determined in order to check their efficacy for wound healing applications. The NCP films were showing significantly higher water absorption capacity, folding endurance, and porosity as compared to the control gelatin (GLT) film. The observed pH of the NCP film was found to be 5.9, which is suitable for human skin. Antibacterial activity of the NCP films against gram-negative bacteria (Escherichia coli) was higher compared to GLT film. The surface roughness was found to be 22.7 nm for the NCP film containing Ag NPs. The thermal stability of the GLT film was improved after the incorporation of Ag NPs. The high antimicrobial activity, porosity and improved surface roughness of NCP films would favour the adherence, growth and proliferation of seeded cells that is pre-requisite for ideal dressing materials.

Cross-linked gelatin film enriched with green carbon quantum dots for bioactive food packaging

Dialdehyde Persian gum (PG) was applied to reinforce the physicomechanical properties of gelatin films through cross-linkage. Carbon dots (CDs) from grape leaves were incorporated into the system to fabricate nanocomposites. Adding oxidized PG to gelatin and CDs up to 5 % improved tensile strength. The solubility of the oxidized PG/gelatin film increased with the addition of CDs. The water vapor transmission of the gelatin film decreased through cross-linking. Adding CDs to the films reduced UV transfer rates but increased the antioxidant activity from 16.66 to 94.08 %. The oxidized PG/gelatin film with CDs showed antibacterial activity against Escherichia coli and Staphylococcus aureus. The fabricated films showed no cell cytotoxicity. Observed decreases in TVB-N and TBARS values, in trout fillets coated with the film containing 30 % CDs, resulted in extended shelf life up to 4 days. Cross-linked gelatin incorporated with CDs offers various applications in the food industry due to its functional properties.

Preparation and characterization of active Cirish fructans-fish gelatin film: Physicochemical, antioxidant, and antimicrobial properties.

This study was aimed to evaluate the film-forming ability and characterization of ultrasonically extracted Cirish fructans (CF) and CF-cold-water fish gelatin (G) composite films. The film-forming solutions were prepared at different levels (CF100-0G, CF75-G25, CF50-G50, CF25-G75, and CF0-G100) and the corresponding data were analyzed based on one-way analysis of variance. The results indicated that CF addition led to an impressive increase in composite films thickness (69.38-86.45 μm), moisture content (16.05%-27.8%), surface hydrophobicity, tensile strength (5.73-17.89 MPa), elongation at break (0.83%-1.66%), Young's modulus (77.12-88.15 MPa), and Tg (38.83-47.4°C) which CF75-G25 had the highest values. Meanwhile, the solubility (77.12%-88.15%), WVP (1.89-2.86 × 10-10gm-1 s-1Pa-1), and oxygen permeability (1.53-3.26 × 1014 cm3m-1s-1Pa-1) of the composite films decreased. The FTIR spectra indicated the protein-polysaccharide interactions and revealed that the secondary structure of gelatin was shifted from triple-helix structure (1661 cm-1) toward α-helix structure (1650-1657 cm-1) when CF was incorporated. The microstructure observations indicated that unlike gelatin film, CF film exhibited the smooth and uniform surface without cracks and phase separation. It was found that CF films had high total phenolic content (6.73 mg GEA g-1) and showed DPPH radical scavenging activity (67.86%). On the other hand, it showed inherent antimicrobial activity against both gram-positive and gram-negative bacteria. The results indicated that CF and CF-cold fish gelatin have great potential as active films with improved physical, mechanical, and barrier properties.

Physical and antioxidant properties of gelatine film added with sesame, rice bran, and coconut oil

Gelatine is commonly used as packaging in the food industry because it has the proper physical properties. The present work observed that there were no differences in moisture content and solubility of the packaging film after adding 4% of gelatine film with 0.5% of rice bran, sesame, and coconut oil. Meanwhile, water vapour permeability, tensile strength, and elongation of the gelatine films increased when added with the oil. The colour value depended on the colour of the oil added to the gelatine films. The colour value of the gelatine films added with sesame and coconut oil did not differ from the gelatine film without the addition of any oil. The addition of coconut oil to the gelatine film resulted in increased antioxidant activity. Wrapping chicken, pork, and beef with the gelatine films added with all three types of oil showed no differences in pH values for all three types of meat products throughout refrigeration storage for 12 days. Meat wrapped in gelatine film added with coconut oil showed an increase in TBARS, while TBARS were lower in the gelatine film without the addition of any oil or added with rice bran and sesame oil. This indicated that after coconut oil was added to the gelatine film, it decreased oxidation in the meat products during storage.

Development of a biomaterial based on chayotextle starch (Sechium Edule)-gelatin blend. Molecular, mechanical, physical, barrier and structural properties

Films made from a mixture of Chayotextle starch-Gelatin (SG) were prepared in concentrations of SG13, SG22 and SG31 respectively. Two controls were considered; gelatin (G) and starch films (S). Glycerol was added as a plasticizer to all treatments at 2%. G treatment presented higher elasticity, permeability and solubility in comparison to those treatments using starch. FT-IR showed that both ingredients gelatin and starch respected their molecular spaces. However, their contribution was relevant for the formation of the matrix of films. The lowest percentage of crystallinity appeared in S films with 30.8%. This value increased up to 48.5 % in the G treatment. The variation of ratios in the mixture gelatin-starch resulted in different degrees of structural composition and these changes could be configured, adapted and applied to the requirements of the food engineering, pharmaceutical, and biomedical industry.

Tough, antibacterial fish scale gelatin/chitosan film with excellent water vapor and UV-blocking performance comprising liquefied chitin and silica sol

Developing biodegradable, and non-toxic materials to replace petrochemical polymers is important. Herein, the waste fish scale-derived gelatin was chosen to prepare an environmental-friendly film. While the natural product of fish scale gelatin (FSG) films has the weakness of low humidity stability, poor antibacterial activity, poor mechanical strength, and weak UV absorption. Hence, a novel multifunctional and mechanically robust FSG-based composite is proposed using chitosan (CTS) as the crosslinking matrix, liquefied chitin product (LCP), and silica sol as the functional fillers. The thermal decomposition kinetics and pyrolysis analysis show that the functional filling components were compatible with the FSG/CTS-based macromolecule matrix. The incorporation of LCP significantly improved the film's flexibility, antibacterial capacity, and UV absorption. The addition of the silica sol also increased the mechanical strength and water tolerance with decreased water vapor permeability (WVP). The increasing apparent activation energy (Ea) along with pyrolysis reactions could correlate well with the composite film's progressive crosslinks. This study demonstrated a renewable FSG/CTS/LCP/Si composite film with a much-improved property that could have potential applications in film-based packaging.

Monitoring the effect of active packaging films with silver-kaolinite using different packaging systems on the quality of beef meat

Active packaging films based on gelatin with silver-kaolinite (Ag-Kln) were developed and their effects on the quality and microbial growth of beef meat stored in different packaging systems (cling film, vacuum and modified atmosphere packaging) at 4 °C for 13 days were evaluated. The analysis revealed that Ag-Kln packaging films had no adverse effects on the pH and colour of the beef samples irrespective of the packaging system used. Beef meat in packaging with active films lost more weight (P < 0.05) than without active films for meat in the vacuum and modified systems on day 13. In general, these gelatin films with Ag-Kln showed the potential as antibacterial films and could enhance the shelf life of food products, however, further studies are required to establish the release rate of silver from packaging films, as well as test the efficiency of these materials under different storage conditions. In conclusion, this study revealed that gelatin film with silver-kaolinite is a promising antibacterial agent and preservation material for food shelf life extension.

Physical, mechanical and antioxidant properties of chicken skin gelatin films incorporated with virgin coconut oil

This study aimed to determine the physical, mechanical, and antioxidant properties of chicken skin gelatin films incorporated with virgin coconut oil (VCO). Prepared chicken skin gelatin films at different VCO concentrations (0–30%) were characterized for their physical (water vapor permeability and light transmission), mechanical (tensile strength, elongation at break), and antioxidant (DPPH scavenging activity and total phenolic content) properties. The tensile strength and elongation at the film's break showed a decreasing and increasing trend with the increase of VCO concentration. The water vapor permeability of films showed no significant difference as the added oil concentration increased. In addition, the films with VCO added showed a good light barrier with a lower light transmission value at a high oil concentration. The incorporation of oil in gelatin films decreases the glass transition temperature (Tg) with the increasing amount of oil. Furthermore, the film's microstructure became rougher and more discontinuous with the addition of oil percentage. The increasing VCO concentration also enhanced the intensity of the Amide A, Amide I, Amide II, and Amide III functional groups. DPPH scavenging activity and total phenolic content in films also increased with VCO concentration. Thus, these results revealed that VCO could be incorporated with gelatin film to make active film packaging or edible film packaging for some food applications for protein-rich food, such as meat or edible packaging for primary packaging.

Nanoliposomes for Sensing Local Osmolarity of the Tear Film on the Corneal Surface.

Purpose: Local hotspots of elevated tear hyperosmolarity (exceeding 900 mOsM) are predicted in dry eye disease (DED) but have not been measured. This study aims to develop, characterize, and evaluate the suitability of fluorescent nanoliposomes for noninvasive sensing of the local osmolarity of the tear film. Methods: Fluorescent nanoliposomes, loaded with calcein (susceptible to self-quenching; sensor dye) and sulforhodamine 101 (SR101; reference dye), were produced by the thin-film hydration method. Results: Dynamic light scattering measurements and Cryo-TEM showed that liposomes were negatively charged (-23.7 ± 1.5 mV), spherical (diameter = 117.9 ± 6.4 nm), and uniform in size (polydispersity index = 0.15 ± 0.02). These properties were unaffected by cold storage (4°C; 14 days), but dye leakage was significant after 3 days. Swelling and shrinkage of the liposomes by exposure to hypoosmotic and hyperosmotic media led to rapid dequenching and quenching of calcein fluorescence (FGreen), with no effect on SR101 fluorescence (FRed). The ratio FGreen/FRed decreased with increasing osmolarity and vice versa, obeying the Boyle van't Hoff relationship. When liposomes were dispersed in a gelatin film with dynamic radial sucrose gradients, local FGreen/FRed decreased with increasing hyperosmolarity as predicted. When instilled on the hydrophilic surface of contact lenses or ex vivo corneas, nanoliposomes dispersed evenly as thin films. Importantly, the measured FGreen/FRed declined continuously with evaporation and consequent increase in their osmolarities. Conclusions: The study provides proof of principle for noninvasive measurement of local tear film osmolarity based on osmosensitive fluorescent nanoliposomes. The strategy can potentially advance our understanding of the pathophysiology of DED.

Stretchable and Electroactive Crosslinked Gelatin for Biodevice and Cell Culture Applications.

Biomimetic substrates that incorporate functionality such as electroactivity and mechanical flexibility, find utility in a variety of biomedical applications. Toward these uses, nature-derived materials such as gelatin offer inherent biocompatibility and sustainable sourcing. However, issues such as high swelling, poor mechanical properties, and lack of stability at biological temperatures limit their use. The enzymatic crosslinking of gelatin via microbial transglutaminase (mTG) yields flexible and robust large area substrates that are stable under physiological conditions. Here, we demonstrate the fabrication and characterization of strong, stretchable, conductive mTG crosslinked gelatin thin films. Incorporation of the conductive polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate in the gel matrix with a bioinspired polydopamine surface coating is used to enable conductivity with enhanced mechanical properties such as extensibility and flexibility, in comparison to plain gelatin or crosslinked gelatin films. The electroconductive substrates are conducive to cell growth, supporting myoblast cell adhesion, viability, and proliferation and could find use in creating active cell culture systems incorporating electrical stimulation. The substrates are responsive to motion such as stretching and bending while being extremely handleable and elastic, making them useful for applications such as electronic skin and flexible bioelectronics. Overall, this work presents facile, yet effective development of bioinspired conductive composites as substrates for bio-integrated devices and functional tissue engineering.

The effect of Klotho protein complexed with nanomaterials on bone mesenchymal stem cell performance in the treatment of diabetic ischaemic ulcer.

A lack of angiogenesis is the key problem in the healing of diabetic foot ulcers. Stem cells have already been proven to have a high potential for angiogenesis. The most important aspects of stem cell therapy are improving the microenvironment, cell homing and continuous factor stimulation. We investigated the effect of Klotho protein to heal wounds by promoting the proliferation and migration of bone mesenchymal stem cells and endothelial cells in vitro. Based on the above study, we produced a compound material by using poly(lactic-co-glycolic acid) (PLGA), chitosan microspheres and gelatin through electro spining technology. The structure of the compound material, just like a sandwich, is that two pieces of PLGA nanofiber films clamped gelatin film which contained chitosan microspheres. In the in vitro release experiment, we could detect the release of Klotho after seven days in the compound material, but the release time was approximately 40 hours for the chitosan microspheres. After seeded bone mesenchymal stem cells (BMSCs) on the surface of the compound material, we observed morphologies of the chitosan microsphere, the PLGA nanofiber and BMSCs by scanning electron microscopy. The nanofiber mesh biological tissue materials could supply an appropriate microenvironment and cell factors for the survival of BMSCs. Compared with the control group, the biological tissue material seeded with BMSCs significantly promoted angiogenesis in the lower limb of diabetic C57BL/6J mice and accelerated diabetic foot wound healing. The compound biomaterial which could continuously stimulate BMSCs through releasing Klotho protein could accelerate wound healing in the diabetic foot and other ischemic ulcers.

Influence of preparation techniques of cellulose II nanocrystals as reinforcement for tannery solid waste-based gelatin composite films.

Tannery waste–based gelatin composite film reinforced with cellulose II nanocrystal (CNC II) extracted from wet wipes using three different hydrolysis techniques is explored for its functional properties and possible utilization as a biodegradable packaging material. CNC II isolated using hydrogen peroxide (PCNC), citric acid (CCNC), and hydrochloric acid (HCNC) differed in morphological and crystalline character as investigated using DLS, FE-SEM, FTIR, and XRD analysis. The crystallinity of PCNC, CCNC, and HCNC was found to be 81.1%, 75.4%, and 86.1%, respectively. The highly crystalline CNC II (PCNC) incorporation improved mechanical stiffness of rawhide trimming waste–based gelatin films by 50% compared to control gelatin film. Maximum thermal decomposition with Tmax of 329 °C was obtained for gelatin films with PCNC nano-reinforcement. Films with CNC II were structurally stable and sufficiently antibacterial against Gram-positive S. aureus microbial strain. Strong interfacial non-covalent and hydrogen bonding interactions between gelatin and cellulose II nanocrystal have likely enhanced the properties of the composite films. Incorporation of CNC II reduced the surface wettability of the films and nanocomposites absorbed UV radiation as evidenced by transmittance value T280 of 0.19%. Nanocomposite films degraded up to 79.9% of initial mass within 7 days of soil burial. Furthermore, based on the optimized system, single-use packaging application of eggplant seeds has been demonstrated.Graphical abstract

Fabrication and characterization of a pH-sensitive indicator film by purple basil leaves extract to monitor the freshness of chicken fillets

This research aimed to fabricate an intelligent film using bovine gelatin and purple basil leaf extract (PBLE). Then the application of the film was investigated to monitor the freshness of chicken fillets. The films were prepared by casting the bovine gelatin solution (75 g/L) with glycerol (30% of dried gelatin) on glass plates and were dried under controlled conditions. PBLE was incorporated into gelatin films (0, 100, 200, and 300 mg anthocyanin from PBLE/kg dried gelatin), and the film characteristics, including physicochemical, antioxidant, antimicrobial, anthocyanin release, and color variations due to pH change, were investigated. The results indicated that the films containing PBLE had a higher thickness, solubility, total phenol content, and antioxidant activity than the control film. The addition of extract improved the antibacterial activity of gelatin films. The release kinetics study showed that the release of anthocyanin from the film was slow, and after 200 min, about 26% of the total anthocyanin content was released from the film. The fabricated films indicated significant color changes from purple to green as pH changed from 4 to 9. The pH-sensitive indicator film also changed from purple to green with TVB-N development (from 8 to 38 mg/100 g) during the storage period of chicken fillets. Therefore, the bovine gelatin-based film containing PBLE can be used as a freshness indicator of chicken fillets.

Chitosan and gelatine biopolymer‐based active/biodegradable packaging for the preservation of fish and fishery products

SummaryFish and fishery products (FFP) are considered nutraceutical foods that are believed to improve human health. FFP are highly prone to deterioration due to microorganisms, oxidation and enzymatic spoilage. Hence, packaging FFP in appropriate material has a pivotal role in shelf‐life extension. Considering the non‐degradable nature and toxicity issues associated with synthetic material, alternatives originating from natural sources have become popular. Chitosan and gelatine are known to exhibit a wide range of bioactivity making them suitable for individual and combined applications for preservation. Chitosan and gelatine films are used for the inclusion of other materials (antimicrobial and antioxidant) to form active packaging with improved properties. The active film formed using chitosan and gelatine exhibits inactivation of microorganisms and inhibits oxidation activity. This review describes the recent knowledge on the development and characterisation of active packaging material by using chitosan and gelatine as well as the application of chitosan and gelatine‐based active films for the preservation of FFP to extend the shelf‐life.

Chitosan-Gelatin Films: Plasticizers/Nanofillers Affect Chain Interactions and Material Properties in Different Ways.

Biopolymers, which are biodegradable and inherently functional, have high potential for specialized applications (e.g., disposable and transient systems and biomedical treatment). For this, it is important to create composite materials with precisely defined chain interactions and tailored properties. This work shows that for a chitosan–gelatin material, both glycerol and isosorbide are effective plasticizers, but isosorbide could additionally disrupt the polyelectrolyte complexation (PEC) between the two biopolymers, which greatly impacts the glass transition temperature (Tg), mechanical properties, and water absorption. While glycerol-plasticized samples without nanofiller or with graphene oxide (GO) showed minimal water uptake, the addition of isosorbide and/or montmorillonite (MMT) made the materials hydrolytically unstable, likely due to disrupted PEC. However, these samples showed an opposite trend in surface hydrophilicity, which means surface chemistry is controlled differently from chain structure. This work highlights different mechanisms that control the different properties of dual-biopolymer systems and provides an updated definition of biopolymer plasticization, and thus could provide important knowledge for the future design of biopolymer composite materials with tailored surface hydrophilicity, overall hygroscopicity, and mechanical properties that meet specific application needs.