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United States Department of Agriculture

Agricultural Research Service

Title: Water Vapor Permeability and Solubility of Zein/starch Hydrophilic Films Prepared from Dry Milled Corn Extract

item Parris, Nicholas
item Dickey, Leland
item Kurantz, Michael
item Moten, Robyn
item Craig Jr, James

Submitted to: Food Technologists Institute
Publication Type: Abstract Only
Publication Acceptance Date: January 10, 1997
Publication Date: N/A
Full Text Available

Technical Abstract: In order to support expansion of the corn ethanol process, profitable markets must be identified for new non-starch coproducts derived from corn. Edible films and coatings have been prepared from grain proteins such as soy, wheat and corn. Wheat gluten and corn zein are alcohol soluble proteins that exhibit hydrophobic properties. Commercially, zein is isolated from corn gluten meal (60%, protein) at 600 C using 88% (v/v) isopropanol contain 0.25 wt% NaOH. In this study, zein films containing different fractions of starch, which did not compromise the physical properties of the film, were prepared by extracting corn previously ground and rinsed using procedures deemed to be practical and economical at large scales. 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. These subunits reportedly contribute to improved antioxidant activity of zein. Water vapor barrier properties of glycerine-plasticized films prepared from extracted zein isolates, containing approximately 8% starch, were comparable to those prepared from commercial zein. Water resistance of zein isolate films decreased with increasing starch content. This research will provide information for the development of biodegradable films having water-proof or grease resistant properties which can be used as alternative packaging to polyolefin wrapping materials.

Last Modified: 4/22/2015
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