15D-13 |
Computer-controlled puffing of bread dough containing potato flour |
S. KATNAS1, E. Bilici2, Z. Hicsasmaz1, and S. Gider3. (1) Food, Agricultural and Biological Engineering, Ohio State University, 590 Woody Hayes Dr., Columbus, OH 43210, (2) Chemical Engineering, Gazi University, Faculty of Engineering and Architecture, Maltepe, Ankara, 06460, Turkey, (3) Food Engineering, Middle East Technical University, Inonu Bulvari, Ankara, 06531, Turkey Complex puffing mechanisms involving phase change; moisture removal and structure formation can be monitored indirectly using puffing rate curves provided by computer control. Addition of potato flour to bread dough results in retarded staling accompanied by changes in crumb structure. Main objective is to study the effect of potato flour on the puffing mechanisms of dough in terms of puffing rate curves, and also, to study the effect of potato flour on the structural properties of the puffed product. We used a hot air circulation tunnel where the air temperature and velocity are computer-controlled, and also moisture removal is monitored with respect to time in the form of puffing rate curves. We applied a 3**k factorial experimental design to study the effect of percentage replacement of wheat flour by potato flour (0-6%), hot air temperature (70 - 90°C) and velocity (2-3m/s) on the puffing rate curves and the structural properties of the product. Selected structural properties were bulk density, expansion ratio, pore area and shape distributions of the product, and the percentage closed pores in the product. We applied response surface analysis to optimize puffing conditions. Bulk density of the product increased with increasing replacement of wheat flour by potato flour that resulted in smaller, spherical, closed pores. Increase in air velocity causing convective currents resulted in premature crust formation leading to increase in bulk density and decrease in expansion ratio. Percentage closed pores increased with increasing temperature due to increased puffing rates. The optimum conditions were obtained by maximization of bulk density and expansion ratio, and minimization of percentage-closed pores at 1% potato flour replacement, 80°C and 2.2m/s hot air velocity. Computer-controlled monitoring of puffing rates can be used to enlighten puffing mechanisms in terms of puffing conditions and with respect to the effect of ingredients on these mechanisms.
Session 15D, Food Engineering: Processing Technologies
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