Correlation between the rheological and technological properties of biscuits with different levels of replacement of wheat flour by rice and azuki bean flour

Summary A mixture design was used to evaluate the effect of replacing (0 to 100%) wheat flour (WF) with wholegrain azuki bean (WABF) and rice (RF) flours on the biscuits quality. High proportions of WABF increased diameter and decreased thickness, whereas WF affected inversely and RF intermediate. The WF biscuit specific volume was 17% greater than that of the dough, and the WABF and RF biscuits were 5 and 13% smaller, respectively. The WABF biscuit hardness was 26.25 N, close to WF (28.14 N), and higher than RF (7.6 N). The WABF increased the colour difference (ΔE) values for biscuits by up to 22.19 and the RF by 1.87. Peak viscosity, breakdown and setback of mixture flours showed positive correlations with the dough hardness and L*, a*, b* and Aw of biscuits and negatively with the radial expansion index and ΔE. The highest global desirability was for biscuits without WF, regardless of crust colour. Effect of different proportions of three types of flour on biscuits characteristics using a simplex centroid design.