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United States Department of Agriculture

Agricultural Research Service

2009 Annual Report

1a.Objectives (from AD-416)
1) Develop thermal (50-90 C) and non-thermal (<25 C) extrusion-based processes that alter the structures of whey proteins (texturize), identify the process conditions, and develop models that relate the conditions to the quality attributes of texturized proteins. .
2)Create co-products linking the texturized whey proteins with carbohydrate and protein polymers such as soy proteins to make health-enhancing products. Characterize the rheological and viscoelastic properties of the texturized whey protein co-products as specialized ingredients with improved quality and functionality.

1b.Approach (from AD-416)
Changes in texture of whey protein concentrates and isolates, alone or in combination with starches and polysaccharides, will be induced through thermal and non-thermal processing. Thermal and non-thermal extrusion process parameters that affect structure and function relative to texturization of whey proteins will be determined. The properties of the shear-texturized proteins, such as elasticity, gelling strength, expansion, foaming and porosity will be evaluated, along with the rheology and network structure shear-induced viscosity changes that result from changes in protein structure. The thermal and non-thermal texturized proteins will be used alone or to create co-products which will be linked with other polymers such as soy, carbohydrates and other dairy proteins, to create functionalized foods such as low carbohydrate or low-glycemic index snacks, meat extenders and meat analogs.

3.Progress Report
Scientist used a variety of modern spectroscopic and microscopic techniques to study changes in the molecular structure of texturized whey protein isolate (WPI) as a result of extrusion treatment to gain insight on the observed increase in digestibility in rat and mouse models compared to the non-texturized counterpart. Experiments were conducted on samples produced under varying extrusion conditions, such as temperature and moisture content, and molecular changes were analyzed as a function of these treatments. New knowledge about the effect of extrusion on molecular structure of WPI can be gained. Results are useful in deriving products with optimal functionality including digestibility.

1. Imitation burgers are made from textured soy or plant proteins. Consumers have little choice outside of soy and plant-based proteins for textured nutritious meat-like products. Dairy products are rich in proteins, vitamins and minerals and can be combined with other food proteins to make textured meat-like products. The proteins were combined using a high speed texturing machine called an extruder, but could not form tough stringy structures. The proteins that combined well such as casein and egg albumin were tested individually or mixed with other proteins at 70 deg C in a spinning flow analyzer had diverse bond types of high relative bond strength. Temperature tests of protein solutions at 70 deg C revealed complex network formation. The networks formed by the proteins were viewed using electron microscopes before and after heating, and showed visible changes in the shapes of the proteins. These results show that the different proteins can be combined to create tough protein foods. Tough chewy proteins will become new outlets for dairy protein ingredients.

6.Technology Transfer


Review Publications
Onwulata, C.I., Flora, L.F., Kramer, W.H. 2008. R&D needs and opportunities in food science and technology. Food Technology. 62(11):41-47.

Tunick, M.H. 2008. Whey Protein Production and Utilization. In: Onwulata, C.I., Huth, P.J., editors. Whey Processing, Functionality and Health Benefits. Ames, IA: Blackwell Publishing and IFT Press. p. 169-184.

Onwulata, C.I., Thomas, A.E., Cooke, P.H. 2009. Effects of Biomass in Polyethylene or Polylactic Acid Composites. Journal of Biobased Materials and Bioenergy. 3(2):172-180.

Last Modified: 4/18/2014
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