Production of pregelatinized sweet potato flour and its effect on batter and cake properties

Abstract

Production of pregelatinized sweet potato flour by drum drying and the effect of pregelatinized flour addition on the properties of cake and frozen cake were evaluated. Drum drying temperature was varied at 110, 120, and 130°C. The water absorption index of pregelatinized flour was significantly higher and the water solubility index was lower than native sweet potato flour. Loss of birefringence in starch granules was observed in all pregelatinized flour. The addition of pregelatinized flour to wheat flour at 5%–15% showed a decrease in peak viscosity, breakdown, and setback values. Low enthalpy of gelatinization and retrogradation was observed in wheat flour substituted with pregelatinized flour. Cake batter viscosity and density increased with increasing pregelatinized flour substitution. Volumes of cake made from wheat flour and wheat flour substituted with pregelatinized flour at 5% were similar. The addition of pregelatinized to wheat flour increased hardness and decreased the enthalpy of fresh and frozen cake. Practical applications Enhanced utilization of white flesh sweet potato flour in the baking industry was studied. Pregelatinized sweet potato flour was produced by economical drum drying. Results revealed the addition of pregelatinized sweet potato flour to wheat flour increased the viscosity and density of cake batter and hardness of cakes. The reduction of retrogradation rate was observed in a cake made from wheat flour substituted with pregelatinized sweet potato flour.