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United States Department of Agriculture

Agricultural Research Service

2008 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 barley and oats proteins. The modified protein will be used in producing low-fat high-protein spoonable salad dressing and mayonnaise. These products will be introduced as healthy products with a reasonable consumer acceptance.

Different biodegradable composites were prepared using biodegradable poly lactic acid as the principle component mixed with milkweed or wheat gluten. The composites showed promising results and good commercial potential. The viscoelastic behavior of wheat protein isolates and corn protein Zein suspensions has been determined using Multiple-Particle Tracking (MPT) technique. This research addresses NP 306, Component 2.

1. Enzymatic isolation-method was developed for barley and oats proteins.

Barley and oats proteins were isolated using three different enzymes. The method was based on enzymatically-degrading the starch and the other carbohydrates of defatted oats or barley flour. After filtration and drying, the remaining material had about 90% native protein. The analytical testing showed that the protein was not damaged during isolation. This information is very important because native proteins are proven to have broader application and better functional properties. This research addresses NP 306, Component 2, Problem Area 2a.

2. The viscoelastic behavior of defatted soy proteins isolated by ultrafiltration-diafiltration (DUD) was investigated.

Conventional isolation methods of producing grain proteins include treatment of grain flour with acid or alcohol followed by centrifugations and/or filtrations. These methods generally can damage the protein functional properties. Purifying of soy proteins using ultrafiltration-diafiltration can preserve protein functionality. However, information regarding the physicochemical properties of soy proteins isolated via DUD is limited in the literature. This information is required for expanding soy protein utilization. In this work, the effects of concentration and temperature on the linear and non-linear viscoelastic properties of DUD soy proteins were studied. Power law model was used to describe the soy protein shearing behaviors. The results provided more insight about the properties and function relationships of the proteins, which will be helpful for developing new food applications. This research addresses NP 306, Component 2, Problem Area 2a.

3. Develop protein-based polymer blends from renewable resource to expand their utilization.

The newly developed methodology is directed for the production of biodegradable polymer composites, which potentially will replace existing petroleum-based polymers. A composite was developed by processing corn protein (zein) and other agricultural biopolymers. This technique has been successfully applied for the production of a biopolymer-composite from most of the agricultural biomass. A correlation between the strength of the starting material and the mechanical property of the final product was observed. Recently, one of the main components of the developed biopolymer composites, zein, was successfully replaced with a far less expensive protein, gliadin from wheat. It was also found that conducting polymer composites can be produced by the inclusion of conducting fillers, such as graphite and charcoal in the developed biopolymer composites. This research addresses NP 306, Component 2, Problem Area 2a.

6.Technology Transfer

Number of Active CRADAs1
Number of Non-Peer Reviewed Presentations and Proceedings1

Review Publications
Mohamed, A., Hojilla-Evangelista, M.P., Peterson, S.C., Biresaw, G. 2007. Barley protein isolate: thermal, functional, rheological and surface properties. Journal of the American Oil Chemists' Society. 84(3):281-288.

Mohamed, A., Rayas-Duarte, P., Xu, J. 2008. Hard red spring wheat / C-trim 20 bread: formulation, processing and texture analysis. Food Chemistry. 107(1):516-524.

Kim, S. 2008. Processing and properties of gluten/zein composite. Bioresource Technology. 99(4):2032-2036.

Liu, S.X., Kim, J., Kim, S. 2008. Effect of polymer surface modification on polymer-protein interaction via hydrophilic polymer grafting. Journal of Food Science. 73(3):E143-E150.

Last Modified: 4/16/2014
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