Abstract This study aimed to understand how adding whole-banana flour (WBF) affected the physicochemical properties of extrudates intended for the development of breakfast flakes. The parameters: WBF addition (50% to 70%, dry basis), feed moisture (27% to 33%, wet basis), and barrel temperature in the last zone of the extruder (80 ºC to 100 °C) were varied according to a 23 factorial design with augmented center points. The addition of WBF linearly affected all the physical and chemical properties evaluated and showed a synergistic effect with barrel temperature for changes in hardness and carbohydrate content. WBF additions above 64.9%, adjusted to feed moisture between 29.6% to 32.6%, and thermomechanically cooked at barrel temperatures above 87 °C, consumed 216 to 257 kJ/kg of mechanical energy, which produced flakes with a hardness between 160 and 180 N. This work could contribute to the incorporation of WBF for developing more nutritious breakfast cereals, with a fiber content greater than 7.2 g/100 g.