Evaluation of functional properties of millet flour ready for use in gluten-free cookie formulations based on rice flour.

Cookies and biscuit  might be included in the list of gluten-free products for patients with celiac disease However, most gluten-free bakery products are commercially based on pure starch, blend of maize starch and gluten-free flour, and protein which lead to dryness and sandy state of the final product. In this regard, there is a strong need to develop gluten-free cookies that are technologically complete as well as economical. The main purpose of this study was to investigate the functional properties of flours and different ratios of millet flour and rice flour (50:50, 25:75, 15:85, 0: 100) in the preparation of gluten-free cookies. Physicochemical properties of millet grain (moisture, fat, protein, ash, and fiber), flour (water absorption, oil absorption), and cookies (diameter, thickness, degree of expansion, color, and stiffness) were also investigated. The results showed that replacing rice flour with higher levels of millet flour led to an increase in water holding capacity (WHC) and decrease in  oil absorption capacity (OAC), significantly (p<0.05). Higher amounts of millet flour showed a significant linear relation with degree of expansion in the cookies (p<0.05) and lightness (L*) of the samples decreased due to increased protein content and Millard reaction. Moreover, higher replacement of rice flour with millet flour in the cookies resulted in higher hardness and cooking loss but lower water activity and lightness(L*). The highest overall accessibility rate was for a cookie containing 15% millet flour