43-7 |
A novel starch derived from oats |
E. VIRTANEN1, R. Bost2, and A. J. Del Vecchio2. (1) Oat Ingredients Business, Avena Group, Kansakoulukatu 1 B, Helsinki, FIN-00100, Finland, (2) Capstone Ingredients, Inc., 368 Front Street, P.O. Box 65, Marion, MA 02738 Of all cereal starches, high-purity oat starch has not been commercially available until recently. Oat starch can be isolated from oat groats or oat flour using conventional wet milling techniques. Oat starch consists of small (3-10 microns) polygonal granules, which typically form agglomerates. Depending on the process and drying conditioins, the agglomerates may partially or completely break down to individual granules. The amylose/amylopectin ratio of oat starch is ca. 30/70, and the amylose bonds a significant amount of phospholipids. Due to this binding, the solubilization of oat starch granules is different from other starches: amylose co-leaches with amylopectin. Although the enthalpy peak of oat starch, when heated, already occurs at 60-65 degrees C, the solubilization requires considerably higher temperatures, >90 deg. C. While the viscosity formation of oat starch at lower temperatures is inferior to many other starches, at high temperatures it swells and forms more viscosity than other native cereal starches so far studied. At moderate shear rate (160 rpm), oat starch gels (10%) formed 56 and 69% more peak and final viscosity than native corn starch. Although shear thinning was somewhat higher, the viscosity of 10% oat starch at 480 rpm was still 20% higher than corn starch. Acid thining was not seen at pH 4; at pH 2.8, the viscosity of oat starch was similar to that of corn starch. Oat starch forms are opaque, short, cuttable gels. Based on its characteristics, oat starch has been tested in spoonable dairy products and extruded cereals and snacks. When compared with modified cornstarch, yoghurt samples with oat starch showed similar viscosity at a 20% lower inclusion rate, similar gel stability and improved aroma and flavor release, especially after 30-day storage. Oat starch produces good swelling and uniform cell structure in extruded applications.
Session 43, New Products & Technologies: Ingredients
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