Properties Of Gelatin Films Research Articles

Film forming ability of gelatins from splendid squid (Loligo formosana) skin bleached with hydrogen peroxide

Properties of gelatin films from splendid squid (Loligo formosana) skin bleached with hydrogen peroxide (H2O2) at various concentrations (0–8% w/v) were investigated. Tensile strength (TS) and water vapour permeability (WVP) of films decreased, but elongation at break (EAB) increased (p<0.05) as the concentration of H2O2 increased. Among all films, that prepared from gelatin with 2% H2O2 bleaching showed the lowest ΔE∗-value (total colour difference), which was concomitant with the highest L∗-value (lightness). Generally, higher concentration of H2O2 resulted in increased b∗-value (yellowness) of resulting films. Electrophoretic study revealed that α-chains of gelatin in films became lowered with increasing H2O2 concentrations used for bleaching. Thermogravimetric analysis indicated that heat susceptibility and weight loss of different films varied with H2O2 concentrations. Rougher surface was obtained in gelatin films prepared from skin bleached with H2O2 concentrations above 4%. Thus, the concentrations of H2O2 used for bleaching of squid skin prior to gelatin extraction directly affected the properties of corresponding gelatin films.

Mechanical, physico-chemical, and antimicrobial properties of gelatin-based film incorporated with catechin-lysozyme.

BackgroundMicrobial activity is a primary cause of deterioration in many foods and is often responsible for reduced quality and safety. Food-borne illnesses associated with E. coli O157:H7, S. aureus, S. enteritidis and L. monocytogenes are a major public health concern throughout the world. A number of methods have been employed to control or prevent the growth of these microorganisms in food. Antimicrobial packaging is one of the most promising active packaging systems for effectively retarding the growth of food spoilage and pathogenic microorganisms. The aim of this study was to determine the mechanical, physico-chemical properties and inhibitory effects of the fish gelatin films against selected food spoilage microorganisms when incorporated with catechin-lysozyme.ResultsThe effect of the catechin-lysozyme combination addition (CLC: 0, 0.125, 0.25, and 0.5%, w/v) on fish gelatin film properties was monitored. At the level of 0.5% addition, the CLC showed the greatest elongation at break (EAB) at 143.17% with 0.039 mm thickness, and the lowest water vapor permeability (WVP) at 6.5 x 10−8 g·mm·h-1·cm-2·Pa-1, whereas the control showed high tensile strength (TS) and the highest WVP. Regarding color attributes, the gelatin film without CLC addition gave the highest lightness (L* 91.95) but lowest in redness (a*-1.29) and yellowness (b* 2.25) values. The light transmission of the film did not significantly decrease and nor did film transparency (p>0.05) with increased CLC. Incorporating CLC could not affect the film microstructure. The solubility of the gelatin based film incorporated with CLC was not affected, especially at a high level of addition (p>0.05). Inhibitory activity of the fish gelatin film against E.coli, S.aureus, L. innocua and S. cerevisiae was concentration dependent.ConclusionsThese findings suggested that CLC incorporation can improve mechanical, physico-chemical, and antimicrobial properties of the resulting films, thus allowing the films to become more applicable in active food packaging.

Manufacture and characterization of gelatin films derived from beef, pork and fish sources using twin screw extrusion

Gelatin films derived from beef, pork and fish sources were manufactured by twin-screw, co-rotating extrusion. The effect of extrusion processing parameters, namely; screw speed (100–400rpm) and temperature (90, 90, 90, 90°C and 90, 120, 90, 90°C) on the mechanical and barrier properties of gelatin films were studied. Increasing screw speed up to 300rpm improved (P<0.05) tensile strength (TS) and reduced (non-significantly) water vapour permeability (WVP) values for all manufactured gelatin films. However, the WVP of various gelatin film types was reduced (P<0.05) when a screw speed of 400rpm was employed. Increasing the speed of extrusion promoted (P<0.05) increased solubility of films in water. Manufacture of films using a higher temperature profile resulted in films possessing higher puncture strengths (PS), increased water barrier properties with higher water solubility.

Use of beef, pork and fish gelatin sources in the manufacture of films and assessment of their composition and mechanical properties

This study investigated the properties of different types of gelatin films from solutions of varying gelatin concentrations (4–8 wt %). Gelatin derived from beef, pork and fish skin sources was used to manufacture films using a casting approach. Mechanical properties of gelatin films, water vapour permeability (WVP), oxygen permeability, oil permeability and aqueous solubility of films were evaluated. FTIR spectroscopy was utilized to assess the composition of various gelatin sources so as to determine differences in composition of these sources and ultimately, in overall functionality. High concentration gelatin films had good mechanical properties with tensile and puncture strengths being particularly improved. Gelatin films manufactured from fish skin had the lowest WVP values for each concentration used. All gelatin films possessed excellent barriers to oxygen and oil. Films derived from pork gelatin exhibited lowest water solubility compared to those formed using beef and fish gelatin sources, regardless of the concentrations used. FTIR spectra showed that plasticizer and gelatin were well mixed and interacted well together. The use of higher concentrations of gelatin had the effect of increasing the wavenumber of amide-A in films due to greater interaction occurring between gelatin functional groups.

Gelatin-assisted fabrication of water-dispersible graphene and its inorganic analogues

Two dimensional nanomaterials are of great significance in a wide range of applications due to their high surface area and novel properties. Here we offer a simple and large-scale method to prepare graphene and its inorganic analogues (MoS2, WS2 and boron nitride) by the sonication of their bulk materials in an aqueous solution of gelatin. The concentrations of the obtained stable dispersions were up to 0.6, 0.8, 0.9 and 1.4 mg mL−1 for graphene, MoS2, WS2 and boron nitride, respectively. Transmission electron microscopy strongly suggests that the materials have been exfoliated into few- or mono-layer thin sheets. Specifically, graphene and MoS2 dispersion have been directly employed to fabricate gelatin–graphene composites. Scanning electron microscope images show that graphene flakes were homogeneously dispersed in the composites. The tensile test results show that the mechanical properties of gelatin films have been remarkably improved by graphene rather than MoS2.

Glyoxal modification of gelatin leads to change in properties of solutions and resulting films

The influence of different pretreated film forming solutions (FFSs) on the physical, chemical and barrier properties of gelatin films was studied. Hydrolyzation with hydrochloric acid and acetylation with acetic acid anhydride at different pHs were performed. Subsequently, gelatin was crosslinked with glyoxal to result in biopolymer films with properties predetermined by the rheological behavior of the respective FFS. Gel time, storage modulus and tan δ of FFSs were obtained from small-strain oscillatory measurements and were correlated with swelling and solubility of the resulting films as well as with chemical analysis of lysine and arginine and the respective amino acid modifications Ne-carboxymethyllysine (CML), glyoxal derived lysine dimer (GOLD) and 5-(2-imino-5-oxo-1-imidazolidinyl)norvaline (imidazolinone). In general, chemical modification reduced the storage modulus whether it was hydrolyzation, acetylation or modification with glyoxal. Treatment by hydrolyzation or acetylation led to differences in gel time and in the ratio between viscous and elastic portion of the different hydrogels, also affecting the relationship between monovalent amino acid modification and bivalent crosslinking after glyoxal addition. Thus, the structural character of FFS hydrogels and of the protein network of films both determined the physical and barrier properties of chemically modified gelatin films.

Role of pH on stability and mechanical properties of gelatin films

The effect of the film-forming solution pH on the triple-helix content, thermal stability, and mechanical properties of gelatin films was investigated. The films were prepared from solutions at different pHs of type A pigskin gelatin, and their mechanical characteristics were determined. At pHs higher than 9 and lower than 5, Young’s modulus, E, and the stress at break, σb, of the films decreased significantly. Cross-linking with genipin reduced deformation at break, ϵb, and increased Young’s modulus. The intensity of the 1.1-nm X-ray diffraction reflection and the denaturation enthalpy decreased at these pHs, indicating that the triple helix reduced. Preliminary in vitro tests on the cross-linked samples indicated good cell proliferation and viability.

Modification of gelatin films using 2-ethylhexyl acrylate by gamma radiation

Gelatin films were prepared from gelatin granules in aqueous medium by casting. Tensile strength, tensile modulus, elongation at break and glass point of the gelatin films were found to be 30 MPa, 450 MPa, 7.1% and 56.5°C, respectively. After irradiation with gamma radiation, the tensile properties increased due to the dense network structure. A series of gelatin solutions was prepared by blending varying percentages (1–10% by wt) of ethylhexyl acrylate and then films were prepared and irradiated with gamma radiation. It was found that the tensile and thermal properties of gelatin films improved significantly. Water uptake of the gelatin films was evaluated.

Physico-mechanical and antimicrobial properties of gelatin film from the skin of unicorn leatherjacket incorporated with essential oils

Gelatin films incorporated with bergamot (BO) and lemongrass oil (LO) at various concentrations as glycerol substitute were prepared and characterised. Incorporation of BO and LO at 5–25% (w/w protein) resulted in the decreases in both tensile strength (TS) and elongation at break (EAB) of the films. Water vapour permeability (WVP) were decreased in LO incorporated films, while it was increased in film added with BO at level higher than 5% (P < 0.05). Film solubility and transparency values decreased, and the films had the lowered light transmission in the visible range when BO and LO were incorporated. Films incorporated with LO showed inhibitory effect in a concentration dependent manner against Escherichia coli, Listeria monocytogenes, Staphylococcus aureus and Salmonella typhimurium, but BO added film inhibited only L. monocytogenes and S. aureus. Films containing both BO and LO did not inhibit Pseudomonas aeruginosa. Significant change of molecular organisation and higher intermolecular interactions among gelatin molecules were found in the film structure as determined by FTIR. Thermo-gravimetric analysis (TGA) demonstrated that films added with BO and LO exhibited enhanced heat stability with higher degradation temperature, compared with control film. Scanning electron microscopic (SEM) images revealed the presence of micro-pores in the essential oil incorporated films, which contributed to physical properties of the resulting films. Thus, gelatin films incorporated with BO and LO can be used as active packaging, but the properties could be modified, depending on essential oil added.

Role of lignosulphonate in properties of fish gelatin films

A commercial low-gelling fish skin gelatin was used to prepare edible films by casting with glycerol and sorbitol added as plasticizers. In order to improve the extremely low water resistance of gelatin films, composite films were prepared with increasing concentrations (wt/wt) of lignosulphonate (LS) from eucalyptus wood (100:0, 85:15, 80:20, 75:25, 70:30 and 65:35, gelatin:LS). How gelatin film properties were affected by the different types of gelatin and LS was determined by comparing bovine gelatin and three different LS (Ca 2+, Mg 2+ and Na +) in a mixture ratio of 80:20. Physical properties of films were characterized in terms of tensile strength, elongation at break, water solubility, water vapour permeability and opacity. Dynamic oscillatory tests of film-forming solutions revealed strong LS interference with the cold-renaturation ability of gelatin. LS ratios equal to or higher than the 80:20 blend interfered with intermolecular aggregation of gelatin helices. Supposedly, LS acted as a filler, inducing mostly nonbonding interactions with gelatin, as deduced from Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR) and Differential Scanning Calorimetry (DSC) studies. Lignosulphonate significantly reduced the elongation at break of fish gelatin films, water solubility being drastically reduced with a mixture ratio of 80:20 or higher. The water solubility of bovine gelatin–LS composite films was significantly lower than that for fish gelatin, regardless of the type of LS employed. For potential food packaging applications, the three LS were characterized in terms of cytotoxicity, radical scavenging capacity (DPPH assay) and antimicrobial capacity. The effective antioxidant levels (IC 50: 83.4–97.5 μg/mL) were noticeably lower than the cytotoxic ones (IC 50: 1480–1745 μg/mL), indicating that these compounds could be used as antioxidants at non-cytotoxic concentrations. No relationship between antioxidant and antimicrobial properties could be observed, the only notable antimicrobial finding being some activity against yeasts.

Proceedings: Mechanical properties of gelatin films.

Proceedings: Mechanical properties of gelatin films.

Effect of glycerol on water sorption of bovine gelatin films in the glassy state

The addition of low molecular weight compounds to a biopolymer in the glassy state can generate changes in macrostructural properties of the matrix. This work studied the effect of glycerol on water sorption properties of gelatin films in the glassy state. Bovine gelatin-glycerol (0-10% dry basis, db) films were equilibrated to moisture contents (MC) in the range of 5 - 30% (db). Results show that the addition of glycerol generated differences in sorption behaviour by the decreasing of sorption parameters (GAB, BET and Freundlich), indicating complex glycerol-matrix interactions. Gas pycnometry showed a densification of the matrix suggesting a reduction in sorption site availability when glycerol content increased.

Study on the Water-Aging Properties of Gelatin-Glucose and Gelatin-Urea Films: The Effect of Gamma Radiation

Thin gelatin films (about 0.25 mm thickness) were prepared from granular gelatin via casting. The mechanical properties of gelatin films such as tensile strength (TS), elongation at break (Eb%), water uptake and water aging properties were investigated. To improve the water aging properties of gelatin films, gelatin-glucose and gelatin–urea films were prepared. Effect of gamma radiation on the tensile properties, water uptake and water aging properties of gelatin-glucose and gelatin-urea films were also studied. The results of the investigation show that both glucose and urea can improve the water stability of the gelatin films.

PENGARUH KELEMBABAN TERHADAP SIFAT OPTIK FILM GELATIN

Humidity Dependence of Optical Properties of Gelatin Films. Humidity dependence of optical properties of gelatin films prepared by casting technique has been investigated. Gelatin films was investigated its optical properties to varied humidity condition. Optical responses investigated are optical transmission and absorption at visible light spectrum measured utilizing a UV-Vis (Ultraviolet – Visible) spectrophotometer. The results of optical transmittance and absorbance obtained shows an optical response of gelatin films in widely visible light spectrum within range 530 – 680 nm, with most clearly response in a spectrum band in 580 – 650 nm. Different humidity treatment cause a significantly change of optical characteristics, that is the transmittance and absorbance change in to humidity. Transmittance of gelatin films increase with increasing humidity in a range 580 – 650 nm, in contrast with absorbance that is decrease with increasing humidity. Plot of transmission and absorption intensity with varied humidity from 37%RH to 99%RH at 610 nm exhibited a good linearity. Two samples showed same characteristics.

Influence of crosslinkers and crosslinking method on the properties of gelatin films extracted from leather solid waste

AbstractGelatin was extracted from chrome tanned leather waste with the aim to produce a durable coating or film. Crosslinking has shown to improve the physical performance of a film/coating. The effect of the method of crosslinking and the use of different crosslinking agents were studied. The extracted gelatin was crosslinked either by immersion of preformed films into a crosslinker solution (Method A) or by the addition of the crosslinking reagent to the gelatin solution prior to film formation (Method B). The different results obtained between both methods may be due to: the relative concentration of crosslinking reagent, the introduction of crosslinks within different regions of gelatin (triple helical regions and random coil regions), and the reaction rate. Method A of crosslinking is more likely to form crosslinks outside but close to the triple helical regions, disrupting the order and stability of the helical structure. Crosslinks may form preferentially within the random coil regions when Method B of crosslinking is used. Both methods led to the formation of chemical crosslinks in the extracted gelatin films, as demonstrated by the reduction of the degree of aqueous swelling and the proportion of low molecular weight fractions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Properties of gelatin films from giant catfish skin and bovine bone: a comparative study

Edible films were prepared from the gelatin of farmed giant catfish skin (GC) (Pangasianodon gigas), bovine bone gelatin (BB) and their combination. The physical, mechanical, thermal and chemical properties of the resulting films were characterized and compared. The molecular weight distributions of the giant catfish skin gelatin-containing samples had high quantities of α-chains, β-components and high molecular weight cross-links. The bovine bone gelatin-containing samples showed low contents of major bands with high degradation band components. The GC films had higher water activity (0.45) and mechanical properties [tensile strength: TS 41 MPa and elongation at break: EAB 34 (%)] but lower thickness (38 μm) and water vapor permeability than those of BB films. The lowest light transmission (200–800 nm) and film transparency (3.34) were found in the GC films. However, the color attribute (L, a and b) of BB films was closer to the low-density polyethylene commercial film (ΔE 1.2). The highest value of film and protein solubility (100%) was found in BB film, while the lowest value (41–56%) was found in GC film. The GC films showed the most compact, smooth and continuous surface without porous structures, which corresponds to the greater properties of films.

Surface modification of dehydrothermal crosslinked gelatin film using a 50 Hz oxygen glow discharge

In this work, an oxygen glow discharge using AC 50 Hz is used for the treatment of type A gelatin film crosslinked by dehydrothermal (DHT) process. The effects of plasma on the properties of gelatin films are investigated. The operating discharge power, pressure and gas flow rate are varied in the range of 3–12 W, 0.4–2 mbar and 3–10 sccm, respectively. The effects of ageing time and temperature on the surface properties of plasma-treated gelatin are also investigated. The results show that the water contact angle of crosslinked gelatin treated by oxygen plasma is lower than that of untreated crosslinked gelatin film. This implies that the oxygen plasma is able to introduce hydrophilic groups onto the surface of the crosslinked gelatin. The efficiency of the surface treatment is increased by increasing the discharge power, increasing the pressure and decreasing the oxygen gas flow rate. The results on atomic force microscopy (AFM) reveal that the surface roughness of the plasma-treated gelatin film is enhanced by increasing the treatment period. The results on ageing tests indicate that at low ageing temperature, the surface properties of plasma-treated gelatin films can be maintained for a longer period as compared to those stored at higher temperature. The change in hydrophilicity during the ageing process is mainly due to the recovery of surface chemistry, not surface roughness. It may be concluded that the AC 50 Hz plasma system can be used effectively to manipulate the surface properties of crosslinked gelatin films.

Effect of Gamma Radiation on the Physico- and Thermo-Mechanical Properties of Gelatin-Based Films Using 2-Hydroxyethyl Methacrylate (HEMA)

Gelatin films were prepared from gelatin granules in aqueous medium by casting. Tensile strength, tensile modulus, elongation at break and the glass point of the gelatin films were found to be 27 MPa, 100 MPa, 4% and 51.7°C, respectively. After irradiated with gamma radiation tensile properties were increased due to denser network structure. Gelatin films were soaked in five different formulations containing 2-hydroxyethyl methacrylate (HEMA) (10–50%, by wt), methanol and photoinitiator and then irradiated under gamma radiation. Again, a series of gelatin solutions was prepared by blending varying percentages (10–50% by wt) of HEMA and then films were prepared and irradiated under gamma radiation. It was found that tensile and thermal properties of gelatin films improved significantly.

Preparation and Mechanical Characterization of Gelatin-Based Films Using 2-Hydroxyethyl Methacrylate Cured by UV Radiation

Gelatin films were prepared from gelatin granules in aqueous medium by casting. Tensile strength, tensile modulus and elongation at break of the gelatin films were found to be 27 MPa, 100 MPa and 4%, respectively. Gelatin films were soaked in five different formulations containing 2-hydroxyethyl methacrylate (HEMA) (10–50%, by wt), methanol and photoinitiator and then cured under UV radiation. Again, a series of gelatin solutions was prepared by blending varying percentages (10–50% by wt) of HEMA and then films were prepared and UV cured. It was found that tensile properties of gelatin films improved significantly.

Effect of Urea on the Mechanical Properties of Gelatin Films Photocured with 2-Ethylhexyl Acrylate

Thin films of gelatin were prepared by casting. Then the films were photocured and the mechanical properties were studied. The tensile strength of UV cured gelatin films showed about 10% enhancement than that of raw gelatin films. Minor amount of urea (1–5%) was used as additive in aqueous gelatin solution and films were prepared using same technique. Four formulations were prepared in methanol with 2-ethylhexyl acrylate in the presence of photoinitiator (darocur-1664). The films were soaked in the prepared formulations and then cured under UV radiation at different intensities (5–25 passes). Percentage of urea, monomer concentration, soaking time and radiation intensities were optimized with the extent of polymer loading, TS and elongation at break of the photocured film. The films containing 2% urea, cured with 3% EHA for 3 min at 15th UV pass showed the highest mechanical properties. A significant improvement of TS (31%) occurred when EHA (3%) was incorporated.