Gelatin-based Films Research Articles

Flavor, antimicrobial activity and physical properties of gelatin film incorporated with of ginger essential oil.

Adding essential oil into the gelatin-based film can enhance the antibacterial activity of the film, but excessive amounts of addition will bring the film an unpleasant flavor and reduce its mechanical performance. Hence, we prepared functional gelatin-based films by incorporating low content of ginger essential oil (GEO). The flavor of GEO was not detected from the films containing less than 1% GEO. The antimicrobial activity of films was found to be proportional to GEO content. As GEO content increased from 0 to 1%, the value of water vapor permeability (WVP) and elongation at break (EAB) increased, whereas the value of tensile strength (TS) of film decreased. The Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy analysis revealed the vibration of gelatin film was affected by adding low content of essential oil. Surface morphologies demonstrated oil droplets and a discontinuous structure, and cross-section morphologies proved the formation of a loose structure as GEO was incorporated in the film through SEM. Sensory evaluation revealed that composite films incorporated with 0.5% GEO exhibited the best performance. The resulting films can be used as antimicrobial packaging materials with good physical properties and sensory performance.

Zinc oxide nanoparticles and periodate oxidation in developing pH-sensitive packaging film based on modified gelatin

Response surface methodology was used to develop pH-sensitive gelatin-based films containing red cabbage extract and zinc oxide nanoparticles (ZnONPs). We also evaluated oxidized sucrose (OS), prepared via the periodate oxidation of sucrose, as a cross-linker to compensate for gelatin solubility. Solubility decreased in films containing higher OS levels. The minimum WVP of the cross-linked gelatin films was obtained at 12.8 % OS and high levels of ZnONPs. Antioxidant activity was reinforced by both ZnONPs and OS. Higher OS concentrations caused decreased opacity, while ZnONPs had the opposite effect. The optimum treatment included 0.043 % ZnONPs and 11.45 % OS. Together, ZnONPs and OS resulted in enhanced strength and decreased flexibility. Greater antimicrobial activity was witnessed against Staphylococcus aureus than Escherichia coli. The optimum film’s color changed from reddish-purple to blue-green between pH 3−12. In summary, we reinforced the gelatin film structure and achieved functional characteristics in a novel, intelligent, and active packaging material.

Multifunctional nanocomposite active packaging materials: Immobilization of quercetin, lactoferrin, and chitosan nanofiber particles in gelatin films

The design and fabrication of multifunctional films from natural materials is a major focus of modern packaging research with the aim of creating smart, active, and/or biodegradable packaging. In this study, multifunctional films were created by embedding different kinds of functional nanoparticles into a gelatin-based film prepared by a casting method. The nanoparticles were prepared by crosslinking cationic chitosan nanofibers using anionic sodium tripolyphosphate ions. In some cases, quercetin, lactoferrin, or both were incorporated into these nanoparticles. The nanoparticles were mixed with the hot gelatin solution prior to casting. The appearance, light-screening, water vapor barrier, thermal, mechanical, antimicrobial, antioxidant, and biodegradability/composting characteristics of the nanoparticle-loaded films were then characterized. Dynamic light scattering showed that the size, polydispersity, and charge of the functional nanoparticles depended on their composition. The spectroscopic analysis identified the importance of electrostatic and hydrogen bonds in film formation. Incorporation of the functional nanoparticles into the gelatin films improved their optical, mechanical, barrier, and preservative properties. For instance, the incorporation of quercetin increased the ability of the films to screen UV-light, whereas the incorporation of both lactoferrin and quercetin increased the antimicrobial and antioxidant properties of the films. Finally, the films were shown to have good biodegradability/composting under environmental conditions, which is important for reducing the negative environmental impacts caused by synthetic packaging.

Analysis of Advanced Glycation End products in ribose-, glucose- and lactose-crosslinked gelatin to correlate the physical changes induced by Maillard reaction in films

The Maillard reaction (MR), a condensation reaction between carbonyl-containing and free amino-containing compounds, has attracted the interest of scientists within the food industry, nutrition & health, and materials science. However, due to the complexity of the reaction much remains to be clarified regarding the nature of the reaction products and their effect on the properties of protein/saccharide-containing products. In this work, gelatin-based films with various saccharides (glucose, lactose & ribose) and thermally crosslinked (105 °C) for different times (0, 2, 6, 24 h), were analysed to deliver deeper insight into the molecular transformations induced by MR and their effect on the physical properties of films, considered as complex systems. Coloured, ultraviolet–visible (UV–Vis) light-absorbing, crosslinked, and fluorescent compounds were analysed by colourimetry, UV–Vis spectrophotometry, solubility, as well as fluorescence spectroscopy. The colour of the films turned pale yellow and dark brown, the solubility decreased, while the UV–Vis light absorption capacity of the films significantly increased as the heating time increased. Rapid and simultaneous separation of Advanced Glycation End products (AGEs) on a silica hydride column, and their detection using high resolution mass spectrometry (MS) showed an increment in high molecular weight (HMW) compounds and gelatin crosslinking, which was related to the formation of AGEs. Of these, pentosidine, vesperlysine, GOLD and MOLD were quantified, while crossline and glucosepane were also detected. More noticeable physical and molecular changes were observed as the saccharide reactivity increased, which was indirectly related to the molecular size of the added saccharides: pentoses > hexoses > disaccharides.

Gelatin Films Activated by Cinnamon Essential Oil and Reinforced with 1D, 2D and 3D Nanomaterials: Physical and Release Controlling Properties

The aim of this study was to assess the effect of sodium montmorillonite (MMT), cellulose nanofibers (CNF) and titanium dioxide nanoparticles (TiO2NPs) on the physicochemical properties and release profile of the gelatin-based film activated with cinnamon essential oil (CEO). The results of FT-IR, XRD, FE-SEM and tensile analysis showed that the incorporation of nanofillers caused to different changes in the morphology, crystalline structure, and mechanical properties of gelatin films that were correlated with their morphology. The water barrier properties of films significantly increased by incorporation of nanofillers and MMT had the highest improving effect. As results of release profile study, MMT incorporated active film exhibited the slowest release rate with the lowest diffusion coefficient (8.67 ± 0.52 × 10−8cm2 s−1 at 25 °C), and highest activation energy (14.87 ± 1.11 kJ mol−1). In conclusion, nanolayers such as MMT were suggested as the best candidate to use as simultaneous reinforcement and release controlling agent in the activated biopolymer-based films.

Novel drug-loaded film forming patch based on gelatin and snail slime

Gelatin-based films enriched with snail slime are proposed as novel biodegradable and naturally bioadhesive patches for cutaneous drug delivery. Films (thickness range 163–248 μm) were stretchable and they adhered firmly onto the wetted skin, especially those with high amount (70% V/V) of snail slime extract. Fluconazole was selected as model drug and added to films containing the highest amount of snail slime. The presence of Fluconazole (4.53 ± 0.07% w/w) did not modify significantly the mechanical properties, the swelling degree and the bioadhesive performances of the films. Structural investigations demonstrated that the crystalline form III of the drug changed to the amorphous one, forming an amorphous solid dispersion. Moreover, snail slime prevented the drug recrystallization over time. In vitro permeation studies showed that film exhibited a cumulative drug concentration (over 60% in 24 h) similar to that of the control solution containing 20% w/V of ethanol. Fluconazole-loaded gelatin films proved to be effective towards clinical isolates of Candida spp. indicating that the drug maintained its remarkable antifungal activity once formulated into gelatin and snail slime-based films. In conclusion, snail slime, thanks to its peculiar composition, has proved to be responsible of optimal skin adhesion, film flexibility and of the formation of a supersaturating drug delivery system able to increase skin permeation.

The effects of agar addition and ultrasound treatment on thermomechanical and physical properties of smooth hound (Mustellus mustellus) skin gelatin film

This study investigates the effect of agar addition and ultrasound treatment on the properties of edible films made from smooth hound (Mustellus mustellus) skin gelatin. The FTIR spectra showed the classic profile of gelatin spectrum presenting three characteristic absorption peaks related to amide I (1620–1690 cm−1), amide II (1540–1580 cm−1) and amide III (1230–1280 cm−1). The agar addition or ultrasound treatment did not cause important influence on FTIR spectra. Agar addition resulted in an improvement of the film rigidity, since blended films of gelatin:agar (25:75) showed important increase of the film tensile strength (12.3 MPa) and a decrease in elongation at break (135%), as compared to the 100% gelatin-based films. All the films were colorless (∆E < 6.8 and opacity < 2.5) and agar addition resulted in a slight increase of the L* values of the blended films that become more transparent. The ultrasound treatment had no significant effect on the mechanical and color properties. The water contact angle was increased for the blended films, which imply the increase of their hydrophobicity. At 120 s the increase in water contact angle was 11.5 and 36.6% for the gelatin:agar (50:50) and (25:75) films, respectively, as compared to the 100% gelatin-based film that suggested a decrease in surface hydrophilicity of the blended films. Agar addition (gelatin:agar; 25:75) decreased the film water solubility by 34%, which suggested that agar could improve their water resistance. Overall, agar addition improved barrier properties of smooth hound gelatin films encouraging their use as a food packaging material.

Fabrication and characterization of composite film based on gelatin and electrospun cellulose acetate fibers incorporating essential oil

In this research, Oliveria decumbens Vent essential oil (OEO) at 0–45% w/w was encapsulated in cellulose acetate (CA) electrospun fibers and then incorporated in gelatin-based films. Scanning Electron Microscope (SEM) showed more uniform and compact surface in the neat gelatin film in comparison to the CA fiber loaded composite ones and microfibers were perpendicular to the fracture surface. The composites showed higher tensile strength (1.3–2.6 MPa) and lower elongation (less than 1%) than the pure gelatin film. Water solubility of the composites were significantly lower than the gelatin film (81% VS. ≈50%). The water vapor permeability (WVP) of composites was higher than the gelatin film probably due to microscopic pinholes induced by fibers, however WVP slightly decreased by increasing OEO. The contact angle values from 79.9 to 101.5° indicating increase of hydrophobicity by incorporating the CA fibers. Inhibition zones against E. coli and S. aureus (13.33 mm) confirmed the antibacterial activity of composites. It can be concluded that the composite gelatin films incorporating EO-loaded electrospun fibers could enhance the mechanical and antimicrobial properties of the composites despite increasing WVP, thus they could be potentially used for food active packaging purposes.

Evaluation of Citrus reticulata essential oil: Chemical composition and antibacterial effectiveness incorporated gelatin on E. coli and S. aureus

ABSTRACT In the present study, we evaluated the antibacterial activity of Citrus reticulata (C. reticulata) essential oil-incorporated gelatin film solution against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The minimum inhibitory concentration (MIC) of C. reticulata essential oil (CrEO) on E. coli and S. aureus were found to be 10.1 and 9.1 mg mL−1, respectively, using spectrophotometric microdilution technique. The antimicrobial effect of CrEO alone and incorporated gelatin-based film solutions (CrEO-F) against these pathogens were determined by the disc diffusion method. While the inhibition zones of CrEO were 2.4 mm and 10.05 mm, CrEO-F was reported as 1.5 and 7.8 mm against E. coli and S. aureus, respectively. These findings demonstrated that the CrEO can compete with coating agents with antimicrobial additives and it can find a place in the application areas. Besides, the chemical composition of the CrEO was determined by GC-MS.

Incorporation of Poly(Itaconic Acid) with Quaternized Thiazole Groups on Gelatin-Based Films for Antimicrobial-Active Food Packaging.

Poly(itaconic acid) (PIA) was synthesized via conventional radical polymerization. Then, functionalization of PIA was carried out by an esterification reaction with the heterocyclic groups of 1,3-thiazole and posterior quaternization by N-alkylation reaction with iodomethane. The modifications were confirmed by Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H-NMR), as well as ζ-potential measurements. Their antimicrobial activity was tested against different Gram-negative and Gram-positive bacteria. After characterization, the resulting polymers were incorporated into gelatin with oxidized starch and glycerol as film adjuvants, and dopamine as crosslinking agent, to develop antimicrobial-active films. The addition of quaternized polymers not only improved the mechanical properties of gelatin formulations, but also decreased the solution absorption capacity during the swelling process. However, the incorporation of synthesized polymers increased the deformation at break values and the water vapor permeability of films. The antioxidant capacity of films was confirmed by radical scavenging ability and, additionally, those films exhibited antimicrobial activity. Therefore, these films can be considered as good candidates for active packaging, ensuring a constant concentration of the active compound on the surface of the food, increasing products’ shelf-life and reducing the environmental impact generated by plastics of petrochemical origin.

Transglutaminase Crosslinked Gelatin Films Extracted from Tanned Leather Waste

The production of biodegradable polymers has proved to be a promising alternative, since these materials have accelerated degradation, contributing to the reduction of residues and the reduction of environmental pollution. The tannery wastes contain considerable collagen and can be used for gelatin extraction and film production for use in agriculture. Gelatin-based films, however, present some challenges for practical application, such as permeability and solubility in water, parameters that can be improved through the crosslinking process by employing enzymes, promoting the union of polymeric gelatin chains. In this context, the action of the enzyme transglutaminase was investigated to improve the properties of gelatin films recovered from leather and chitosan residues, which were evaluated according to thickness, solubility, permeability, mechanical properties, and soil degradation. The results indicated that the enzyme concentration in the films had a significant effect on the properties of water permeability and solubility and strain to rupture. The evaluation of soil degradation showed that films with higher enzyme addition took longer to be degraded.

Wettability of gelatin-based films: The effects of hydrophilic or hydrophobic plasticizers and nanoparticle loads

Abstract The effects on surface properties of films with compositions based on gelatin plasticized with glycerol, without or with montmorillonite (MMT), and plasticized with acetyl tributyl citrate (ATC) was investigated. The water contact angle (WCA), wettability and free surface energy were determined by measuring the WCA using the sessile drop method. The surface topography was measured by AFM. The film plasticized by glycerol presented the smoothest surface, while the film loaded with MMT presented the greatest surface roughness followed by that plasticized by ATC. All films showed a hydrophobic character (WCA>65°), and the same trend was observed for wettability. It is worth mentioning that there was no significant correlation between the values of WAC and roughness. The films showed low polar component values, which corroborate the high WCA values obtained. In conclusion, the MMT load or the use of ATC did not expressively improve the humidity resistance of films based on gelatin.

Effects of bovine gelatin viscosity on gelatin-based edible film mechanical, physical and morphological properties

This study was conducted to determine the effect of gelatin reology on mechanical, physical and morphological properties of gelatin-based edible films. The aim of this study was to better understand the variation of viscosity on the structural behaviour of gelatin-based films in the presence of glycerol and sorbitol plasticizers. Gelatin-based films were casted by using gelatins of different viscosities as 2.5, 3.0 and 3.5 centipoise with plasticisers as glycerol and sorbitol. Finally, the physical, mechanical and morphological properties of the films were investigated via pH, thickness, tensile strength and elongation, fourier transform infrared spectroscopy and scanning electron microscopy. As a result of the study, it was observed that a durable film structure could be obtained with gelatin viscosity at 3 centipoise. Furthermore 5.5% gelatin, 0.1% glycerol and 0.4% sorbitol concentration were found as the most suitable formulation for gelatin based film structure with Tukey Test. The results suggest that gelatin-plastisizer combinations can be an excellent source of biobased packaging material with further investigations.

Bi-layer Gelatin Film: Activating Film by Incorporation of “Pitanga” Leaf Hydroethanolic Extract and/or Nisin in the Second Layer

Active films have gained increasing interest because of their potential to reduce the amount of additives into foods. The aim of this work was to produce and characterize bi-layer films based on gelatin in both layers, in which the nisin and/or “pitanga” leaf hydroethanolic extract was loaded in the second layer. The bi-layer gelatin-based films were characterized regarding humidity and solubility in water, color, microstructure, mechanical properties, water contact angle, water vapor permeability, UV/Vis barrier, X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, and antimicrobial and antioxidant activities. The addition of active compounds on the second layer of the films was sufficient to produce active films. The presence of additives in the films’ second layer did not affect film humidity, water vapor permeability, or the molecular interactions of the polymer matrix as assessed by FTIR. Although some mechanical properties and the water contact angle were affected, it was not necessarily deleterious to the films’ functionality. All active films presented activity against Staphylococcus aureus and Listeria monocytogenes even with the additive being present only in a thin layer. And, as it could be expected, only films containing PLHE presented antioxidant activity. This study concluded that the bi-layer technique permits the production of active films while employing only one third of the amount of additives when compared to similar monolayer films of the same thickness, as produced in a previous work.

Fish Gelatin-based Films for Gas Sensing.

Electronic noses (e-noses) mimic the complex biological olfactory system, usually including an array of gas sensors to act as the olfactory receptors and a trained computer with signal-processing and pattern recognition tools as the brain. In this work, a new stimuli-responsive material is shown, consisting of self-assembled droplets of liquid crystal and ionic liquid stabilised within a fish gelatin matrix. These materials change their opto/electrical properties upon contact with volatile organic compounds (VOCs). By using an in-house developed e-nose, these new gas-sensing films yield characteristic optical signals for VOCs from different chemical classes. A support vector machine classifier was implemented based on 12 features of the signals. The results show that the films are excellent identifying hydrocarbon VOCs (toluene, heptane and hexane) (95% accuracy) but lower performance was found to other VOCs, resulting in an overall 60.4% accuracy. Even though they are not reusable, these sustainable gas-sensing films are stable throughout time and reproducible, opening several opportunities for future optoelectronic devices and artificial olfaction systems.

Effect of Proteolytic Enzymes on The Biological Degradability of Gelatin-Based Films

Effect of Proteolytic Enzymes on The Biological Degradability of Gelatin-Based Films

Gelatin-based films activated with red propolis ethanolic extract and essential oils

Red propolis ethanolic extract (RPEE) and essential oils are well-known for their antimicrobial and antioxidant activities. The aim of this study was to develop gelatin-based active films loaded with RPEE in combinations with clove essential oil and/or basil essential oil and to study the effects of these components on the antioxidant, antimicrobial and physical properties of films. The active films were produced by a spreading technique, with RPEE and essential oils in different concentrations. These compounds were evaluated for antioxidant and antimicrobial activities, as well as for their minimal inhibitory concentration and minimal bactericidal concentration. The films were characterized through physical, antimicrobial and antioxidant properties. RPEE and essential oils both presented high antioxidant activity. All essential oils showed antimicrobial activity against all evaluated bacteria, while the RPEE presented activity only against the Gram(+) bacteria. All films showed antioxidant activity. Films with clove essential oil presented the highest total contents of phenol and antioxidant activity. The RPEE in films increased their UV/visible light barrier and modified their thermal properties. Changes in infrared spectra suggested possible interactions between phenols of the active compounds and the gelatin peptides. Overall, physical properties of active films were typical of biopolymer-based films.

Bioactive edible films: Development and characterization of gelatin edible films incorporated with casein phosphopeptides

This study aimed to investigate the effects of bioactive casein phosphopeptides (CPPS) (0, 0.1, 0.2, 0.3 and 0.5% (w/v)) on physico-mechanical, structural, antimicrobial and antioxidant characteristics of gelatin-based films. The results demonstrated that the addition of CPPs to gelatin films significantly decreased solubility and water vapor permeability (WVP) of the treatments G-CPP0.1, G-CPP0.2 and G-CPP0.3, but the optimal treatment was achieved in treatment G-CPP0.1 (4.46 × 10−12 g (m s Pa)−1 of WVP and 43.5% of solubility). The light transmittance decreased with increasing CPPs concentration in the films, achieving the lowest transmittance (0–11.2%) of UV light in the 200–350 nm range. Treatment G-CPP0.1 showed improved mechanical properties such as the highest TS (18.14 MPa) and EAB (84.1%). FTIR and DSC analysis indicated suitable interactions between gelatin and CPPS functional groups in the sample G-CPP0.1. Gelatin-CPPS films showed good inhibitory effects against the tested Gram-positive microorganisms (Staphylococcus aureus and Bacillus cereus) by increasing the concentration of CPP in the composite film. In addition, they presented effective antioxidant activity by DPPH test (2,2-diphenyl-1-picryl hydrazide). In general, the results showed that the gelatin-CPPS edible films with lower CPP concentrations (0.1–0.2% of CPP) could be potentially used in food packaging to ensure the quality of food products, due to their suitable physico-mechanical properties and enhanced bioactive characteristics.

Structural, thermal, and mechanical properties of gelatin-based films integrated with tara gum

Films with different morphology can be obtained by mixing fish gelatin, Tara gum and glycerol in different ratio and by subjecting the Tara gum to a ball milling treatment before its use. The amount of the plasticizer glycerol, as well as the type of Tara gum employed (as received or milled) resulted, from SEM and AFM analyses, to strong influencing the morphology of the films and their density. Also, the morphological differences determine different thermal and mechanical behaviours. In particular, the employment of milled Tara gum allows to improve the thermal stability, as well as the mechanical properties of the polymers. A similar outcome can be obtained by increasing the glycerol content, which can be used up to 20 wt%. Glycerol amounts exceeding that percentage, are detrimental for the quality of the films and reduce their thermal and mechanical performances.

Preparation and characterization of gelatin/β-glucan nanocomposite film incorporated with ZnO nanoparticles as an active food packaging system

In this study, nanocomposite film as biodegradable active packaging was fabricated by incorporation of gelatin and β-glucan (0, 10, and 20% w/w) in the presence of ZnO nanoparticles (0, 2.5, and 5% w/w); further, it was characterized by XRD, DSC, SEM, and FT-IR analyses. The obtained results exhibited that the incorporation of ZnONPs and β-glucan had no adverse effect on the morphological and thermal properties and the crystallinity of gelatin-based films, indicating appropriate interaction and good compatibility between gelatin matrix, ZnONPs, and β-glucan. Moreover, the increasing concentrations of β-glucan and ZnONPs increased strain to break and the ultimate tensile strength of film samples. The film samples containing a high concentration of ZnONPs showed higher water barrier properties (moisture absorption and water vapor permeability) and surface hydrophobicity. Additionally, the incorporation of ZnONPs in the film samples provided high antibacterial activity against foodborne pathogenic bacteria. In conclusion, the ZnONPs and β-glucan incorporated gelatin-based nanocomposite film could be applied as an active food-packaging system due to its unique features.