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Characterization of biodegradable films obtained from cysteine-mediated polymerized gliadins
- Hernandez-Munoz, P., Kanavouras, A., Villalobos, R., Chiralt, A.
- Journal of agricultural and food chemistry 2004 v.52 no.26 pp. 7897-7904
- gliadin, polymerization, crosslinking, cysteine, biodegradable products, films (materials), disulfide bonds, packaging materials, mechanical properties, glass transition temperature, tensile strength, ethanol, solubility, thermal properties
- This study focuses on the effect exerted by interchain disulfide bonds on the functional properties of films made from gliadins when cross-linked with cysteine. Gliadins were extracted from commercial wheat gluten with 70% aqueous ethanol, and cysteine was added to the film-forming solution to promote cross-linking between protein chains. The formation of interchain disulfide bonds was assessed by SDS-PAGE analysis. Gliadin films treated with cysteine maintain their integrity in water and become less extensible while their tensile strength increases as a consequence of the development of a more rigid network. The glass transition temperature of cross-linked films shifts to slightly higher values. The plasticizing effects of glycerol and moisture are also demonstrated. The mechanical behavior of cysteine-cross-linked gliadin films was compared to that of polymeric glutenins. Cross-linked gliadins displayed tensile strength values similar to those of glutenin films but achieved slightly lower elongation values. Cysteine-cross-linked gliadin films present the advantage that they are ethanol soluble, facilitating film fabrication or their application as a coating for food or for any other film or surface.