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Sihan Li

Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)


Agricultural and Biosystems Engineering

First Advisor

Zhengrong Gu


Zein is the main storage protein of corn gluten meal.Due to its water resisting property, oxygenation barrier and the easiness in the fabrication of large films, zein is widely used in food,papermaking,printing,textile, medical, health and so on. Current studies mainly focused on the extraction of zein from gluten meal. However, the yellow color and bad odor of zein has limited its application, especially in fruit and vegetable packaging.Although AC has been used as an adsorbent to decolor and deodorize zein, recovery of corn zein and the decolorization efficiency were low. Thus, in this research, a new effective adsorbent was investigated to decolor and deodorize corn zein. Three single factor experiments were conducted using temperature, time and liquid/solid ratio as factors on the extraction rate of zein. Based on the result of the single factor experiments, an orthogonal experiment was developed to evaluate the effectiveness of time, temperature and liquid/solid ratio on the yield. The most significant factor that affected the yield was temperature. The liquid-solid ratio was the second significant factor and time was the third significant factor. The optimal condition of extraction of zein was extraction time 1.5 h, liquid-solid ratio 15:1, and extraction temperature 50 °C. Under this condition the yield of zein was 48.65 %. Four single factor experiments were conducted to investigate the optimal condition for decolorization using AC. The optimal decolorization condition was ethanol concentration 85%, decolor time 2 hrs, decolor temperature 50 °C and solid/liquid 1.5:100. Under this condition the discolorations reached to 76.7%. Silica-carbon composite was proved to be an effective adsorbent by which 80-90% color and bad odor were removed with a 20-40% protein lost. Although using AC (H2O-CO2 pretreated AC) derived almost the same result of decolorization with the silica-carbon composite, the protein lost was double.

Library of Congress Subject Headings

Corn -- Processing
Extraction (Chemistry)
Carbon, Activated -- Absorption and adsorption
Silica -- Absorption and adsorption


Includes bibliographical references (pages 80-91)



Number of Pages



South Dakota State University


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