Ethanolic extraction of zein from maize

Zein can be extracted from maize (Zea mays) using ethanol solutions, and re covered from the extract by diluting with water. Dilution to 40% ethanol wi ll precipitate a mixture of zein and maize lipid with similar to 15% lipid. For possible zein applications, such as film production. purer zein is req uired. Most of the lipid can be removed from the precipitate by selective r e-extraction with hexane or ethanol, but this is expensive. A precipitate c ontaining 90% or more of the protein in the extract, with less than 10% lip id. can be obtained by diluting the extract in stages. An initial dilution will precipitate a solid with 75% or more lipid, this precipitate can be ce ntrifuged from the extract and the centrifugate diluted to precipitate a so lid of 70% or more zein. The mass and composition of solid centrifuged from a maize extract that was diluted in several steps to characterize the comp osition of precipitates so formed. The lipid content of a zein product prec ipitated from an extract diluted from 55% ethanol to 50% is significantly l ower than the content of precipitate of an extract diluted in a single step to 40% ethanol. Published by Elsevier Science B.V.