The Solubility of the Corn Protein Zein in Ionic Liquids Compared to Conventional Solvents

The corn protein zein is a commercially useful biopolymer with practical applications in biodegradeable plastics, inks, coatings, and fabrics. However, zein’s high cost of production makes it difficult to use in a low margin environment. It may be possible to use ionic liquids as solvents and as reaction media to lower the production cost of zein.

This research presents the solubility of zein in 3 protic and 4 aprotic imidazolium-based ionic liquids and the molecular solvents acetic acid and 1-methylimidazole. Our findings show that zein is more soluble in some ionic liquids than the commercially used aqueous ethanol solvent. For example, the protic ionic liquid 1-methylimidaozlium acetate can dissolve up to .262 wt% zein at 60 ºC, compared to 70 vol% aqueous ethanol that can dissolve only .082 wt% zein at 60 ºC. This research will be used to identify ideal properties of potential ionic liquid solvents for zein production.t