The Use of Aqueous Urea as Chemical Denaturant in Processing CGM into a Biodegradable Polymer Material

Corn gluten meal (CGM) has potential as a bioderived polymer for use in composite materials. Previous work to improve the processability of CGM has focused on the use of plasticisers including water, polyethylene glycol, glycerol and octanoic acid, however, a common problem is that these leach from the material subsequent to processing [1]. It has been raised that a certain degree of denaturation must occur in order to make proteins processable [2]. The current work explores the use of aqueous urea as chemical denaturant in processing CGM into a biodegradable polymer material. Consolidated materials were obtained which showed increased resistance to cracking with higher urea concentration. FTIR analysis revealed that processing CGM with increased concentrations of aqueous urea resulted in the progressive transformation of the protein secondary structure from an ordered, clustered conformation to that of extended chains. Aqueous urea is assumed to promote protein-solvent interactions which stabilise the extended chain conformations.