Water vapor permeability and solubility of zein/starch hydrophilic films prepared from dry milled corn extract

Zein films containing different levels of starch were prepared from extracts of dry milled corn which had been previously rinsed in a hydrocyclone to improve the extractability of the zein as well as film formation. Zein was isolated from the rinsed dry milled corn by extraction with 70% (v/v) ethanol. Comparison of RP-HPLC profiles indicated the presence of beta- and gamma-zeins in the extracted isolate which were not found in commercial zein. Water vapor barrier properties of the glycerine-plasticized films prepared from extracted zein isolates, containing approximately 8% starch, were comparable to films prepared from commercial zein. Water resistance of zein isolate films decreased with increasing starch content. (C) 1997 Elsevier Science Limited.