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Gelatin Films (gelatin + film)

Distribution by Scientific Domains

Chemistry	100%

Selected Abstracts

Water Vapor Permeability of Mammalian and Fish Gelatin Films

JOURNAL OF FOOD SCIENCE, Issue 4 2006
R.J. Avena-Bustillos
ABSTRACT:, Water vapor permeability of cold- and warm-water fish skin gelatins films was evaluated and compared with different types of mammalian gelatins. Alaskan pollock and salmon gelatins were extracted from frozen skins, others were obtained from commercial sources. Water vapor permeability of gelatin films was determined considering differences on percent relative humidity (%RH) at the film underside. Molecular weight distribution, amino acid composition, gel strength, viscoelastic properties, pH, and clarity were also determined for each gelatin. Water vapor permeability of cold-water fish gelatin films (0.93 gmm/m2hkPa) was significantly lower than warm-water fish and mammalian gelatin films (1.31 and 1.88 gmm/m2hkPa, respectively) at 25 °C, 0/80 %RH through 0.05-mm thickness films. This was related to increased hydrophobicity due to reduced amounts of proline and hydroxyproline in cold-water fish gelatins. As expected, gel strength and gel setting temperatures were lower for cold-water fish gelatin than either warm-water fish gelatins or mammalian gelatins. This study demonstrated significant differences in physical, chemical, and rheological properties between mammalian and fish gelatins. Lower water vapor permeability of fish gelatin films can be useful particularly for applications related to reducing water loss from encapsulated drugs and refrigerated or frozen food systems. [source]

Study on Glucose Biofuel Cells Using an Electrochemical Noise Device

ELECTROANALYSIS, Issue 14 2008
Yueming Tan
Abstract An electrochemical noise (ECN) device was utilized for the first time to study and characterize a glucose/O2 membraneless biofuel cell (BFC) and a monopolar glucose BFC. In the glucose/O2 membraneless BFC, ferrocene (Fc) and glucose oxidase (GOD) were immobilized on a multiwalled carbon nanotubes (MWCNTs)/Au electrode with a gelatin film at the anode; and laccase (Lac) and an electron mediator, 2,2,-azinobis (3-ethylbenzothiazoline-6-sulfonate) diammonium salt (ABTS), were immobilized on a MWCNTs/Au electrode with polypyrrole at the cathode. This BFC was performed in a stirred acetate buffer solution (pH,5.0) containing 40,mmol/L glucose in air, with a maximum power density of 8,,W/cm2, an open-circuit cell voltage of 0.29,V, and a short-circuit current density of 85,,A/cm2, respectively. The cell current at the load of 100,k, retained 78.9% of the initial value after continuous discharging for 15,h in a stirred acetate buffer solution (pH,5.0) containing 40,mmol/L glucose in air. The performance decrease of the BFC resulted mainly from the leakage of the ABTS mediator immobilized at the cathode, as revealed by the two-channel quartz crystal microbalance technique. In addition, a monopolar glucose BFC was performed with the same anode as that in the glucose/O2 membraneless BFC in a stirred phosphate buffer solution (pH,7.0) containing 40,mmol/L glucose, and a carbon cathode in Nafion-membrane-isolated acidic KMnO4, with a maximum power density of 115,,W/cm2, an open-circuit cell voltage of 1.24,V, and a short-circuit current density of 202,,A/cm2, respectively, which are superior to those of the glucose/O2 membraneless BFC. A modification of the anode with MWCNTs for the monopolar glucose BFC increased the maximum power density by a factor of 1.8. The ECN device is highly recommended as a convenient, real-time and sensitive technique for BFC studies. [source]

Characterization of Fish-Skin Gelatin Gels and Films Containing the Antimicrobial Enzyme Lysozyme

JOURNAL OF FOOD SCIENCE, Issue 5 2006
C.K. Bower
ABSTRACT:, Fish skins are rich in collagen and can be used to produce food-grade gelatin. Films cast from fish-skin gelatins are stable at room temperature and can act as a barrier when applied to foods. Lysozyme is a food-safe, antimicrobial enzyme that can also produce gels and films. When cold-water, fish-skin gelatin is enhanced with lysozyme, the resulting film has antimicrobial properties. The objective of this study was to characterize the effect on strength and barrier properties of lysozyme-enhanced fish-skin gelatin gels and films, and evaluate their activity against potential spoilage bacteria. Solutions containing 6.67% fish-skin gelatin were formulated to contain varying levels of hen-egg-white lysozyme. Gels were evaluated for strength, clarity, and viscoelastic properties. Films were evaluated for water activity, water vapor permeability, and antimicrobial barrier capabilities. Fish-skin gels containing 0.1% and 0.01% lysozyme had pH (4.8) and gelling-temperatures (2.1 °C) similar to lysozyme-free fish-skin gelatin controls. However, gel strength decreased (up to 20%). Turbidities of gels, with or without lysozyme, were comparable at all concentrations. Films cast with gelatin containing lysozyme demonstrated similar water vapor permeabilities and water activities. Lysozyme was still detectable in most fish gelatin films. More antimicrobial activity was retained in films cast with higher lysozyme concentrations and in films where lysozyme was added after the gelatin had been initially heated. These results suggest that fish-skin gelatin gels and films, when formulated with lysozyme, may provide a unique, functional barrier to increase the shelf life of food products. [source]