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United States Department of Agriculture

Agricultural Research Service

2009 Annual Report

1a.Objectives (from AD-416)
Use starch-lipid composites produced by steam jet cooking to create new products from bio-based resources. Determine the effect of process variables and mechanisms of interactions that influence the properties of starch-lipid composites. Cooperate with licensees and CRADA partners to investigate specific combinations of ingredients designed to provide new applications.

1b.Approach (from AD-416)
Investigate the properties of starch-lipid composites prepared using cereal flour instead of starch, mixtures of starch and polysaccharide gums, and dairy sources of lipids. Vary the starch/lipid ratio and determine the maximum lipid content possible. Vary process variables such as steam pressure, steam and slurry flow rates, temperature, and high-shear mixing before or after jet cooking and determine the effects on composite properties. Cooperate with CRADA partners to develop products based on starch/lipid composites in the areas of food products (meats, dairy products, baked good, etc.), water-based lubricants, cosmetics and drug delivery products, and industrial or environmental microbial delivery systems.

3.Progress Report
Basic studies of the chemical interactions in jet-cooked starch-lipid composites and numerous product development investigations were accomplished. (1) A method was developed for applying thin polyethylene coatings to starch films, using the same mechanism by which jet-cooked starch forms coatings on oil droplets. The effects of solvent type and the structure of polyethylene deposits were determined. This method affords protection from water exposure for some starch film applications. (2) A new potential platform technology was developed by preparing dispersions of amylose helical inclusion complexes with sodium palmitate by steam jet cooking. The consistency of dispersions could be readily varied from thin liquid to firm gel by adjusting the pH, salinity, or solids content. Variations of this technique will be used to develop a wide variety of new food and industrial applications in a future research project. (3) Carbon black, a lipophilic solid, was jet-cooked with starch to form stable dispersions, and the observed aggregates of carbon black particles could be further reduced in size by sonication. Coalescence of smaller particles with time after sonication was found to be a very loose association which could be redispersed with minimal shear. Freeze-dried starch-carbon black composites instantly dispersed in water to yield a smooth, inky liquid. These starch-carbon black composites will provide a new, bio-based medium for water-miscible ink products. (4) High-oil flour composites were developed as a fat delivery ingredient for dry cake mixes. Cakes made with composites retained their softness and moisture better than control cakes made with equivalent flour and oil. Low-fat cake frostings were prepared from composites, made with high amylose starch jet-cooked with oleic acid, into which shortening was blended. Texture, melting behavior, extrudability, and stability were similar to commercial frostings. These two studies demonstrate the potential for using starch-lipid composite technology for improving the quality and nutritional profile of foods. (5) A new method of elastomeric composite preparation using helical inclusion complexes from jet-cooked high-amylose starch was shown to yield significant reinforcement properties in styrene-butadiene rubber. Acid precipitation of the complexes is believed to form small particles which provide the improved reinforcement. This study provides a new bio-based alternative material for reinforced rubber products with different color and biodegradability properties. (6) Octadecyl acrylate was shown to form helical inclusion complexes with amylose. The physical properties of the complexes were examined in order to determine their suitability as an agent for synthesizing starch graft copolymers more easily than established chemical methods. The overall impact of these studies includes the realization that amylose-lipid helical inclusion complexes provide an important new platform technology for biobased products, and the demonstration of specific, new product classes for the original jet-cooked starch-lipid composite technology.

1. Preparation of amylose helical inclusion complexes by excess steam jet cooking: This method of producing such complexes uses water and steam, and is more environmentally benign than other techniques for producing these complexes which use solvents or chemical reagents. The ability of excess steam jet cooking to substantially solubilize starch provided an opportunity to supplement the starch with fatty acids, fatty acid salts, and various lipophilic materials specifically to form helical inclusion complexes. The physical characteristics of jet-cooked amylose complexes made with sodium salts of fatty acids could be readily manipulated by changes in pH, salinity, or solids content to provide a wide range of textures and viscosities. Networks of spherulites obtained by jet-cooking amylose-containing starch with oleic acid provided a medium in which to suspend high volume fractions of oil in aqueous preparations without droplet coalescence. These findings will allow the development of a new platform technology based on thermomechanically produced helical inclusion complexes that will enable the delivery of host molecules and spherulite suspensions for a wide variety of food and industrial products. The technology is the subject of a new patent application.

2. Polyethylene coatings on dried starch films: The utilization of dried starch films is limited by their water absorption and wettability in many circumstances. Ways to make the surface of starch films more hydrophobic are needed. The stability of aqueous starch-oil composites is based on the formation of starch coatings on oil droplets. It was previously shown that similar starch coatings could be applied to polyethylene (PE) films. By inverting the phases of this system, it was possible to use hot organic solvent solutions of PE to form PE deposits on starch films that were dried on a teflon surface. The effects of temperature, cooling rate, and PE concentration were determined. The orientation of hydrophobic portions of starch molecules on the side of starch films in contact with teflon caused a much higher amount of PE to be deposited on that side. This technique could allow the application of a water-resistant layer to protect starch film products from water absorption, which would increase the range of applications for starch films.

3. Food applications for starch-lipid composites: Commercial utilization of jet-cooked starch lipid composites in food applications by manufacturers has been shown to proceed more quickly when the initial demonstration of a given food product has been validated by a laboratory study which establishes the efficacy and advantage of the technique. Jet-cooked composites containing wheat flour and canola oil were drum dried and used to replace oil and part of the flour in low-fat cake mix formulations. Cakes made with the composites were softer and had more spring as measured by texture analysis. The cakes made with composites retained their softness and moisture better than control cakes made with equivalent flour and oil. Starch-shortening composites were prepared by jet-cooking starch and oleic acid, then blending in shortening. Composites were used to substitute for shortening in the low-fat butter cream cake frostings. Rheology, texture and storage studies indicate that amylose composites can be used to prepare low-fat frostings with good properties. In addition to these laboratory studies, composites were evaluated by CRADA partners and licensees for use in low-fat muffin mixes and ground beef patties Adding only fat-soluble flavors as the lipid phase allowed the flavor delivery benefits with minimal fat content. These studies will provide baseline formulations which manufacturers can customize to adapt them to their established production systems and provide the desired product qualities.

6.Technology Transfer

Number of Active CRADAs1
Number of New Patent Applications Filed1

Review Publications
Singh, M., Byars, J.A. 2009. Starch-Lipid Composites in Plain Set Yogurt. International Journal of Food Science and Technology. 44(1):106-110.

Byars, J.A., Fanta, G.F., Felker, F.C. 2009. Rheological Properties of Dispersions of Spherulites from Jet-Cooked High-Amylose Corn Starch and Fatty Acids. Cereal Chemistry. 86(1):76-81.

Singh, M., Kim, S. 2009. Yogurt Fermentation in the Presence of Starch-Lipid Composite. Journal of Food Science. 74(2):C85-C89.

Kim, D., Bae, I., Inglett, G.E., Lee, S. 2009. Effect of Hydrothermal Treatment on the Physicochemical, Rheological, and Oil-Resistant Properties of Rice Flour. Journal of Texture Studies. 40(2):192-207.

Fanta, G.F., Salch, J., Felker, F.C., Shogren, R.L. 2009. Adsorption of Polyethylene from Solution onto Starch Film Surfaces. Journal of Applied Polymer Science. 114(3):1840-1847.

Last Modified: 4/18/2014
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