Designing new materials from wheat protein.
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.
Woerdeman
Dara L
DL
Metallurgy and Materials Engineering Department and Laboratory of Food Chemistry, Katholieke Universiteit Leuven, B-3001 Heverlee, Belgium.
Veraverbeke
Wim S
WS
Parnas
Richard S
RS
Johnson
Dave
D
Delcour
Jan A
JA
Verpoest
Ignaas
I
Plummer
Christopher J G
CJ
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
D003432:Cross-Linking Reagents; D010940:Plant Proteins; D013438:Sulfhydryl Compounds; D014867:Water; D005983:Glutens