Submitted to: Cereal Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/17/2004
Publication Date: 1/10/2005
Citation: Biswas, A., Sessa, D.J., Lawton Jr, J.W., Gordon, S.H., Willett, J.L. 2005. Microwave assisted rapid modification of zein by octenyl succinic anhydride[abstract]. Cereal Chemistry. 82(1):1-3. Interpretive Summary: Zein, the major protein in corn, has long been investigated for uses other than food or feed. Applications for zein in the past have included adhesives, coatings, fibers, and plastics. Unfortunately, most of these applications have been lost to synthetic materials from the petroleum industry. Potential exists for zein to be used in some of these applications if it can be modified to meet the existing need. This study investigates using an organic solvent and microwave heating to carry out the modification. Zein was chemically modified with octenyl succinic anhydridge (OSA), a chemical extensively used for starch modification. Using the organic solvent dimethyl formamide allowed for a more efficient reaction than if the reaction was ran in water or alcohol. Fast reaction time of less than five minutes was achieved by heating in a microwave. The anydridge group of OSA reacted with zein and the structure of this modified OSA-zein was confirmed by protein nuclear magnetic resonance and infra-red spectroscopy. New modifications of zein to better meet end uses will increase the likelihood of it being used in both new and old applications.
Technical Abstract: Corn is one of the most important food and industrial crops in the U.S. and zein constitutes about half of its endosperm proteins in corn. Potential applications of zein include use in fiber, adhesive, ink, cosmetic, textile and chewing gum. Recently, attempts have been conducted to utilize zein for food coatings and biodegradable materials. The new applications of zein require it to be resistant to water. Thus, we are on the lookout for new routes of chemical modification of zein (Biswas et al 2003). 2-Octenyl succinic anhydridge (OSA) is extensively used in modifying food starches. Our objective was to take advantage of OSA's hydophobicity, flexibility and compatability with non polar groups and incorporate OSA onto zein. This OSA modified zein would possess the best of both OSA and zein. A zein solution in dimethyl formamide (DMF) was reacted with various levels of OSA to give a modified zein. In a microwave reactor the reactions proceeded tremendously fast and they were over in five minutes. The anhydridge group of OSA reacted with the hydroxyl/amine group of zein to form ester/amide of zein. The structures of OSA modified zein were confirmed by proton NMR and IR spectroscopy. The preliminary evaluation showed that zein and OSA modified zein had comparable mechanical properties.