Characterization of biodegradable films obtained from cysteine-mediated polymerized gliadins.
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.
Hernandez-Munoz
Pilar
P
School of Packaging, Michigan State University, East Lansing, Michigan 48824, USA. phernan@iata.csic.es
Kanavouras
Antonis
A
Villalobos
Ricardo
R
Chiralt
Amparo
A
D001673:Biodegradation, Environmental; D003545:Cysteine / Q000737:chemistry*; D004220:Disulfides / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D018857:Food Packaging / Q000295:instrumentation*; D005903:Gliadin / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D013718:Tensile Strength
D004220:Disulfides; D011108:Polymers; D005903:Gliadin; D003545:Cysteine