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United States Department of Agriculture

Agricultural Research Service

2010 Annual Report

1a.Objectives (from AD-416)
Improve the functional properties of wheat, oat, and barley seed proteins by investigating isolation techniques, protein modification, and protein blends. Specific objectives include: (1) Develop cereal protein materials having specific and desirable characteristics, and determine the origin of the alterations occurring during the currently employed grain protein isolation methods. Initiate new protein materials with maximum functional properties. Determine the effect of commercially existing isolation methods on the functional properties of wheat, barley, and oat proteins; (2) Establish new and fundamental information on the physical, rheological, and mechanical properties of seed proteins that is of vital importance in developing new uses and new markets for seed proteins; and (3) Develop protein-based polymer blends from renewable resources to expand their utilization. The newly developed products will serve as alternatives to petroleum-based polymers.

1b.Approach (from AD-416)
Functional properties of isolated seed proteins will be evaluated and enhanced by chemical and enzymatic modification. Proteins will be characterized by field-flow fractionation, high performance liquid chromatography, capillary electrophoresis, thermal analysis, and ultracentrifugation. Rheological characterization of native and processed proteins will be made using a stress-controlled rheometer, a Diffusing Wave Spectrometer, and a newly developed Multiple Particle Tracking System. Blends of proteins with other polymers will be formulated for specific applications and their phase behavior, aggregation, and mechanical properties characterized.

3.Progress Report
Significant progress has been made on the isolation and modification of wheat, lupin, and oats proteins. Food products development and formulations from different grain proteins is the focus of this project. One of the main components of National Program 306 is to develop value added products from generally undervalued agricultural commodities. Therefore, this project is consistent with the functions of NP 306. The thermo-rheological properties of the isolated/modified proteins were determined in addition to both linear and non-linear viscoelastic properties for wheat and oats proteins. The thermo-rheological information of the isolated/modified proteins was used in developing high potassium/high protein bread formulations. The modified proteins will also be used in low-fat type products. These products will be introduced as healthy/ nutritious specialty products with good consumer acceptance. Overall, these products will reduce the daily fat intake and increase the nutritional value of bread and salad dressing due to the high protein content. In the non-food objectives of this project, various biodegradable composites with promising characteristics were developed. Different biodegradable composites were prepared using biodegradable polylactic acid, polycaprolactone, and wheat gluten blends. The developed composites showed promising results and potential for commercialization. Due to the presence of gluten, polylactic acid lost some of its mechanical properties. This problem was addressed by adding a compatibilizer (polymeric diphenylmethane diisocyanate) to the composites in order to maintain properties of the principal polymer, polylactic acid or polycaprolactone. The possibility of intermolecular interactions in crosslinked polyester/gluten blends was explored by infrared analysis and the data was correlated with the thermal properties of the composites. The use of proteins will reduce the overall cost of the expensive biodegradable plastics, improve biodegradability, and reduce the need for synthetic polymers. In addition, this project is planning to improve the properties of these composites by adding nanoparticles (nanoclays). This will be one of the focuses of the next five year project plan.

1. The viscoelastic behaviors of wheat gluten and protease treated gluten. Wheat gluten is one of the most important components of wheat flour and it has been widely used in food and non-food applications. The rheological properties of gluten are the least understood, due to its complicated molecular structure, causing delay in its application. To circumvent this problem, gluten was chemically modified and enzymatically-manipulated. The enzyme treated gluten exhibited different functional properties. Such modification will expand its utilization. The chemical modification was done to change the surface properties of gluten and render it compatible with different synthetic polymers. In order to study the effect of enzymes on the functionality of gluten, thermal and viscoelastic property experiments were designed for gluten treated with different types and levels of enzymes. The information obtained from this work will be helpful for developing new applications in food and non-food products. Since vital gluten is mostly used as an ingredient for improving the baking quality of different wheat flours, this modified gluten application can potentially expand to other applications such as spray-dried flavor encapsulators, confectionary products, and as filler for biodegradable plastics being researched by Plant Polymer Unit scientists at the National Center for Agricultural Utilization Research in Peoria, IL.

2. Protein-enriched and potassium or soluble fiber supplemented bread. High soluble-fiber bread is often rejected by consumers due to dense texture and short shelf life, and eating two bananas a day to meet the daily intake of potassium is too much for some women. Therefore, we have developed bread formulations to address both problems by adding banana powder and vital gluten to wheat flour. Banana powder contains both soluble fiber and high potassium, but to get the daily potassium intake we needed to replace 25% of the flour with banana powder. Consequently, the bread was dense and that may cause consumer rejection regardless of its nutritional value. Plant Polymer Unit scientists at the National Center for Agricultural Utilization Research in Peoria, IL, adjusted the formulation by adding vital gluten thus increasing the overall protein content of the bread. This formulation will allow women to get their daily potassium intake by consuming one slice of bread a day. These formulations can be commercialized by any business, small or large.

Review Publications
Mohamed, A., Finkenstadt, V.L., Palmquist, D.E., Rayas-Duarte, P. 2009. Thermal Properties of Extruded Injection-Molded Poly (lactic acid) and Milkweed Composites: Degradation Kinetics and Enthalpic Relaxation. Journal of Applied Polymer Science. 111:175-184.

Mohamed, A., Xu, J., Singh, M. 2010. Yeast leavened banana-bread: formulation, processing, color and texture analysis. Food Chemistry. 118:620-626.

Last Modified: 4/18/2014
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