Location: Plant Polymer Research
2006 Annual Report
FY 2006 & 2007 1a. Determine factors that cause gelation and aggregation in zein solutions. 1b. Optimize for extracting germ protein and characterize functional properties of recovered proteins. 1c. Establish process to enzymatic cross-link zein to itself or other proteins. 2a. Formulation studies of glue mix: evaluation of plywood processing and adhesive strength. 2b. Characterization of the chemical and functional properties of proteins fractionated by UF/DF. 2c. Evaluate tensile properties of zein, CGM, and DDG produced by extrusion processing and compression molding. 2d. Determine the impact of various chemical modification on zein structure and their impact on rheological properties.
FY 2008 & 2009 1a. Establish process to keep zein from gelling or aggregating while in solution. 1b. Evaluate properties of zein gels and determine value added markets for the gels. 1c. Modification of germ proteins for food and nonfood uses. 2a. Optimization of formulations for protein extenders in plywood glue and economic analysis. 2b. Process modification or optimization of UF/DF method for protein fractionation. 2c. Optimize compounded zein and CGM for injection molder and analyze materials. 2d. Develop processing model to relate processing conditions with zein properties. Modify zein through living radical polymerization to olefins.
To improve the economics of bio-ethanol new value added co-products are needed from the process. Corn germ is removed during corn processing and its protein can be recovered. We determined that protein extraction at 40 deg C increase the yields substantially compared with the previous extractions done at ambient conditions. These proteins can be useful at meat binder/extender, thickener, nutritional supplement, or adhesive.
The development of new applications for zein which involve solvent processing requires knowledge of its solution behavior. Different laboratory extraction methods were used to prepare zein samples. The viscosities of dilute solutions of these zein samples in aqueous alcohol solvents were measured over several weeks. It was found that the intrinsic viscosity, a measure of the molecular size of zein in solution, was dependent on the source of zein, and for a given source was relatively stable over a period of several weeks. The intrinsic viscosity was also dependent on solvent, and attempts to correlate intrinsic viscosity results with spectroscopic data obtained in the same solvent were begun. These results provide insight into the stability of zein solutions, and provide baseline data for approaches to solving the gelation problem often encountered with zein solutions.
Demonstrated a pilot-scale production of a decolorized, deodorized zein protein isolate (>90% protein) from ground corn meal. Zein protein isolate was extracted from corn meal using 70% aqueous ethanol and purified by using ultrafiltration/diafiltration and activated carbon. Zein isolation as the first step in a bio-ethanol plant will improve the overall economics of fuel ethanol by providing a value added co-product for the process. An international company has evaluated this protein isolate which was found to meet their rigid qualifications. A CRADA with Illinois Corn Marketing Board (ICMB) entitled "Flavor and Color Removal from Corn Zein Products" ended in 2005. Currently the technology is being evaluated at The National Corn-to-Ethanol Research Center and plans are underway to implement the technology in a new bio-ethanol facility.
Determined that grinding soybean meal to mesh 40-mesh particle size was a beneficial step in preparing soybean meal prior to mixing with other ingredients in the plywood glue formulation (solubility and dispersion markedly improved). This step will allow soybean meal to be used as an extender in plywood adhesives and thereby provide an additional market for soybean meal.
Demonstrated that zein can be extracted in 100% ethanol at temperatures above 90 deg C. This method has the advantage over traditional zein extraction methods of easier zein recovery. When the zein ethanol solution is cooled below 70 deg C, the zein precipitate can be recovered through centrifugation or screening. Traditional methods require drying techniques such as spray drying to drive off the solvent or cryogenic cooling to precipitate zein. This new extraction method has the potential to lower the isolation cost of producing zein, and thereby lowering the price of zein.
In an effort to understand fundamental aspects of zein gelation in aqueous ethanol, the flow properties of dilute zein solutions were characterized. Over the temperature range studied, no significant effect of temperature was observed. Ageing the solutions for up to six weeks had no significant effect for laboratory-extracted zein samples, while commercial zein samples slightly increased in viscosity. There were significant differences between lots of commercial zein. These results provide insight into the fundamental solution properties of zein and will be useful to others in zein research.
Hojillaevangelist, M.P., Evangelista, R.L. 2006. Functional properties of proteins in lesquerella seed and press cake from oil processing [abstract]. American Oil Chemists' Society Meeting. p.108.
Lawton Jr, J.W. 2005. Isolation of zein using 100% ethanol [abstract]. AACC Meeting. p.1.
Sessa, D.J., Byars, J.A., Selling, G.W. 2006. Mechanical properties of films from zein reacted with glutaraldehyde [abstract]. Corn Utilization and Technology Conference. p. 43.
Momany, F.A., Sessa, D.J., Lawton Jr, J.W., Selling, G.W., Hamaker, S.A., Willett, J.L. 2005. Structural characterization of a-zein. Journal of Agriculture and Food Chemistry. 54:p.543-547.