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United States Department of Agriculture

Agricultural Research Service


Location: Plant Polymer Research

2006 Annual Report

1.What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? Why does it matter?
This project is part of National Program 306 "Quality and Utilization of Agricultural Products". The goals of this project are to develop new chemistries and processes to enhance the utilization of co-products produced by industrial agricultural processing, thereby generating new markets for these co-products. New industrial markets need to be found for the co-products produced from the corn and soybean refining and bioethanol industries. These co-products have traditionally found outlets in the livestock feeding industry. The increasing supply of co-products is becoming available at the same time that traditional consumption in livestock feed is diminishing. Co-products from other industries, such as fisheries are also adding to the economic pressure of the co-products of corn and soybean refiners. New technology that allows for the conversion of these co-products into new products would not only decrease the chances of these materials being in surplus, but also add an economic benefit to the overall refining process. New uses for the co-products derived from bioethanol fuel production are critical for the success of that industry. Research will center on developing technologies and processes which will impart unique and acceptable properties to plant proteins. The research involves two main objectives: 1)Characterize the physical and chemical properties of the proteins in co-products from cereal and soy processing, and bioethanol production to find unique properties; 2)Utilize their unique properties to produce value added materials such as adhesives, fiber, films, and plastics, as a result of processing and chemical modification.

2.List by year the currently approved milestones (indicators of research progress)
FY 2005 1a. Extract and purify zein samples. 1b. Develop and evaluate protocols for extraction of germ protein. 1c. Evaluate fluorescent probes to monitor zein reactions. 2a. Demonstrate the functional properties and mixing performance of protein extenders for plywood glue. 2b. Produce protein fractions from soybean meal by UF/DF (ultrafiltration/diafiltration) and traditional methods. 2c. Evaluate the melts of zein, CGM (corn gluten meal), and DDG (distillers dry grain) in a torque rheometer. 2d. Define classes of compounds that improve zein processiblity.

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.

4a.List the single most significant research accomplishment during FY 2006.
DEVELOPMENT OF NEW USES OF PROTEIN CO-PRODUCTS. This research contributes to solving problems in support of ARS National Program 306, Quality and Utilization of Agricultural Products and addresses Problem Statement 2b, New Uses for Agricultural By-Products. New uses of the protein co-product at bio-ethanol manufacturing facilities are needed to keep these materials from being in surplus and to help the overall economics. Research was conducted that showed that corn gluten meal (CGM) could be compounded in a twin screw extruder and injected molded into articles. The tensile strength of the CGM samples is sufficient to be useful in a one time use item such as planter pots. Planter pots made from CGM would not only be bio-degradable, but have the added benefit of being a nitrogen source and a herbicide if planted with the plant.

4b.List other significant research accomplishment(s), if any.
IMPROVING ECONOMICS OF BIO-ETHANOL CO-PRODUCTS. This research contributes to ARS National Program 306, Quality and Utilization of Agricultural Products and addresses Problem Statement 2b, New Uses for Agricultural By-Products. One such co-product "zein" can easily be extracted at a bio-ethanol facility, but needs new uses to prove economic. We have found that zein can be electrospun into non-woven sheets using a varity of solvents. Acetic acid produces zein fibers with round morphology while alcoholic solvents product flat ribbons. Zein electrospun fibers are birefringent with the magnitude of biofringence increasing as fiber diameter decreases.

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.

4c.List significant activities that support special target populations.

4d.Progress report.
Research progress in FY2006 & FY2007 is documented in Questions 4a and 4b.

5.Describe the major accomplishments to date and their predicted or actual impact.
Research accomplishments for this project support Component 2, New Processes, New Uses, and Value-added Foods and Biobased Products, of National Program 306, and specifically address Problem Area 2a, New Uses for Agricultural By-products.

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.

6.What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end-user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products?
Zein extraction methods and technologies to produce odorless and tasteless zein have been passed on to bio-ethanol producers through a CRADA with the Illinois Corn Marketing Board (ICMB). An additional CRADA with ICMB is in place to study and improve the properties of zein.

7.List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below).

Review Publications
Selling, G.W., Sessa, D.J., Lawton Jr, J.W. 2005. Routes to improved physical properties and processing of zein [abstract]. CD-ROM. International Chemical Congress of Pacific Basin.

Lawton Jr, J.W. 2006. Corn gluten meal as a plastic for agricultural applications [abstract]. American Oil Chemists Society. p.107.

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.

Last Modified: 4/19/2014
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