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Effect of soluble, insoluble and gel forming fibers on extensional properties of dough
H. DOGAN (1), M. Fajardo-Perez (1), Y. Zhao (1) (1) Kansas State University, Manhattan, KS, U.S.A..

A low intake of dietary fiber has been linked with health problems including diverticular disease, diabetes, obesity, coronary heart disease, and colorectal cancer. By incorporating fiber into baked products, consumers would be able to meet the recommended daily fiber intake; however, the addition of fiber into dough systems changes the rheological properties which in turn affect the final quality. The purpose of this study was to understand the effects of soluble and insoluble fibers on dough development and functionality. Dough samples containing one of six different fibers (oat, inulin, dextrin, resistant starch, pectin, fiber gel) at 2, 5, or 10% replacement levels were tested. The MixoLab (Chopin) and Kieffer Dough Extensibility Rig (Texture Technologies) were used to assess the mixing and pasting behavior, and the extensional properties, respectively. Results indicated that insoluble fibers minimally affect water absorption, while soluble fibers decrease the water absorption, and gel forming fibers increase the water absorption. Both insoluble and gel forming fibers increased the peak viscosity while soluble fibers decreased it. The soluble fibers provided longer stability during mixing; however, they caused a decrease in the peak viscosity and delayed the point of gelatinization. The insoluble fibers caused a slightly early onset of gelatinization while the gel forming fibers caused a delay in gelatinization. Insoluble and soluble fibers displayed a wide extent of changes in their resistance (Rmax) and extensibility (Ext). Gel forming fibers caused development of short dough as indicated by low Ext values, while presence of soluble fibers created soft (low Rmax) and highly extensible (high Ext) dough.