title: Enhancing water repellence and mechanical properties of gelatin films by tannin addition.
abstract: In order to reduce pollution caused by traditional non-biodegradable plastic films, renewable raw materials from plants and wastes of meat industries have been employed in this work. A hydrolysable chestnut-tree tannin was used for gelatin modification. Films of gelatin and gelatin-tannin were obtained by casting at room conditions. Transition temperatures of both gelatin and gelatin-tannin systems were determined by differential scanning calorimetry (DSC). Glass transition temperatures of modified gelatin occurred at higher temperatures than for neat gelatin. Enthalpy and temperature of helix-coil transition decreased when tannin content increased due to variations in the helical structure of gelatin as a consequence of tannin presence in agreement with X-ray analysis. Mechanical and thermal behaviour varied as a function of the content of tannin, showing optimum values for films modified with 10 wt% tannin. The transparency of films was maintained after modification with tannin. Solubility and swelling tests of the films revealed that the presence of tannin reduced the water affinity of gelatin.
authors.affiliation: Materials+Technologies' Group, Department of Chemical and Environmental Engineering, Polytechnic School, University of the Basque Country, Pza. Europa, 1, 20018 Donostia-San Sebastián, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Peña
authors.forename: Koro
authors.initials: K
authors.lastname: de la Caba
authors.forename: Arantxa
authors.initials: A
authors.lastname: Eceiza
authors.forename: Roxana
authors.initials: R
authors.lastname: Ruseckaite
authors.forename: Iñaki
authors.initials: I
authors.lastname: Mondragon
mesh_terms: D002152:Calorimetry, Differential Scanning; D005780:Gelatin / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013634:Tannins / Q000737:chemistry*; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*; D014965:X-Rays
chemical_list: D013634:Tannins; D014867:Water; D005780:Gelatin