Author
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Lawton Jr, John |
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Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 4/30/2005 Publication Date: 9/11/2005 Citation: Lawton Jr, J.W. 2005. Isolation of zein using 100% ethanol [abstract]. AACC Meeting. p.1. Interpretive Summary: Technical Abstract: Traditionally zein is isolated and recovered from corn gluten meal using aqueous alcohol as the extractant. Aqueous isopropanol is used in commercial isolation of zein, but aqueous ethanol has also been used. Recovery of zein from these solvents is inconvenient. In the laboratory, dialysis against water is often used. Commercially, cryogenics is used, where the extractant is cooled and the zein is precipitated. Zein is soluble in absolute ethanol at 120 deg C. The advantage of using absolute ethanol at high temperatures is that zein is not soluble in this solvent at room temperature and as the extractant cools the zein precipitates and can easily be recovered and dried. Corn gluten meal was extracted with absolute ethanol in a high pressure reactor at 130 deg C. After extracting at 130 deg C for 45 min., the solution was pumped out of the extractor and allowed to cool. The precipitate was removed from the solution and air dried, resulting in 22 to 26% recovery of the starting material. The recovered precipitate had an average protein content of 85% giving a theoretical recovery of about 50% of the zein. The disadvantage of this method is the time needed to extract at high temperatures causes some browning of the zein. Currently, a flow through extraction device is being used to minimize the time zein is at high temperature. |
