Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/15/2011
Publication Date: 4/16/2011
Citation: Byars, J.A., Fanta, G.F., Felker, F.C. 2011. Rheological properties of starch-oil composites with high oil:starch ratios. Cereal Chemistry. 88(3):260-263. Interpretive Summary: Excess steam jet cooking is a process that has been used at NCAUR to develop a number of important products. One way to expand the range of applications would be to increase the oil-holding capacity of starch-oil composites with this technology. This work shows that if high amylose corn starch is jet cooked with oleic acid and soybean oil, high amounts of oil can be trapped in starch aggregates. The flow properties, viscosity, texture, and microstructure of these high-oil composites was determined and described. These materials can be used in applications such as spray lubricants, lotions and foods. Consumers and producers of these product types will benefit as specific product formulations and large scale manufacturing techniques are developed.
Technical Abstract: Many applications have been developed for aqueous dispersions of jet-cooked starch-oil composites prepared by excess steam jet cooking. Previous formulations have typically contained between 20% and 50% oil by weight based on the weight of starch. In order to expand the range of potential applications, new preparation methods were investigated to increase the oil content to as high as four times the weight of starch. High amylose corn starch was cooked in an excess-steam jet cooker in the presence of oleic acid, and soybean oil was added to form the starch-oil composites. Amylose is removed from solution by forming helical inclusion complexes with the oleic acid, and if the materials are cooled sufficiently quickly the helical inclusion complexes only form small aggregates and shells around the oil droplets, and not a firm gel. Depending on the composition and preparation method, a wide range of stable, high-oil materials from low-viscosity liquids to smooth pastes can be formed. The flow, textural and structural properties of these materials are shown. The materials can be used in a wide range of applications, including spray lubricants, lotions, and for fat delivery in cake mixes.