title: Designing new materials from wheat protein.
abstract: We recently discovered that wheat gluten could be formed into a tough, plasticlike substance when thiol-terminated, star-branched molecules are incorporated directly into the protein structure. This discovery offers the exciting possibility of developing biodegradable high-performance engineering plastics and composites from renewable resources that are competitive with their synthetic counterparts. Wheat gluten powder is available at a cost of less than dollars 0.5/lb, so if processing costs can be controlled, an inexpensive alternative to synthetic polymers may be possible. In the present work, we demonstrate the ability to toughen an otherwise brittle protein-based material by increasing the yield stress and strain-to-failure, without compromising stiffness. Water absorption results suggest that the cross-link density of the polymer is increased by the presence of the thiol-terminated, star-branched additive in the protein. Size-exclusion high performance liquid chromatography data of molded tri-thiol-modified gluten are consistent with that of a polymer that has been further cross-linked when compared directly with unmodified gluten, handled under identical conditions. Remarkably, the mechanical properties of our gluten formulations stored in ambient conditions were found to improve with time.
authors.affiliation: Metallurgy and Materials Engineering Department and Laboratory of Food Chemistry, Katholieke Universiteit Leuven, B-3001 Heverlee, Belgium.
authors.forename: Dara L
authors.initials: DL
authors.lastname: Woerdeman
authors.forename: Wim S
authors.initials: WS
authors.lastname: Veraverbeke
authors.forename: Richard S
authors.initials: RS
authors.lastname: Parnas
authors.forename: Dave
authors.initials: D
authors.lastname: Johnson
authors.forename: Jan A
authors.initials: JA
authors.lastname: Delcour
authors.forename: Ignaas
authors.initials: I
authors.lastname: Verpoest
authors.forename: Christopher J G
authors.initials: CJ
authors.lastname: Plummer
mesh_terms: D000042:Absorption; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003432:Cross-Linking Reagents / Q000737:chemistry; D005983:Glutens / Q000737:chemistry*; D008422:Materials Testing; D015394:Molecular Structure; D008970:Molecular Weight; D010940:Plant Proteins / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013718:Tensile Strength; D013997:Time Factors; D014908:Triticum / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D003432:Cross-Linking Reagents; D010940:Plant Proteins; D013438:Sulfhydryl Compounds; D014867:Water; D005983:Glutens