The impact of restricted substitution of wheat flour with tannia flour on the physico-chemical and sensory properties of cookies

The feasibility of wheat flour substitution with tannia flour in the production of cookies was investigated. The tannia flour studied were native tannia flour (NTF) and pregelatinized tannia flour (PTF). NTF was made by drying the sliced tannia tuber at 70 oC and then milled and sieved through a 60 mesh sieve. PTF was made using a hydro-thermal technique that was by boiling sliced tannia tuber in hot water (95 oC) for 10 minutes before drying. Partial substitution of wheat flour with NTF or PTF was done at the level of 50%. The physical, chemical, sensory, and microstructural properties of the cookies produced were evaluated. Microstructural studies were performed using a scanning electron microscope (SEM). The results showed that substitution of wheat flour with tannia flour had a significant effect on sensory properties (texture); physical properties (hardness, color, and microstructure); and chemical properties (protein, carbohydrate, ash, and curd fiber content). Replacement of 50% wheat flour with PTF produced cookies that compete well with 100% wheat flour cookies (control) in term of sensory, physical, and chemical aspects. The PTF substituted cookies had lower protein level compared to the control cookies, but it had higher crude fiber content. Moreover, the PTF substituted cookies contained 5.94% protein, 24.52% fat, 63.10% carbohydrate, and 1.92% crude fiber, and it was a low-gluten and fiber-rich cookie.