Effect of soy milk powder addition on staling of soy bread

► The effect of each soy milk component on breads physicochemical properties was studied. ► Soymilk powder addition reduced firmness and amylopectin retrogradation at the end of storage. ► Synergistic effect of soluble fibre, partly denatured soy proteins and lipid was observed. Effect of soy milk components (soluble fibre (SF), insoluble fibre (ISF), soy protein) on physicochemical properties (crust and crumb colour, water activity, total moisture content, “freezable” water (FW), “unfreezable” water (UFW), amylopectin recrystallisation (ARC), stiffness and firmness) of soy breads stored for 7days was studied. By the end of storage ISF additions significantly increased ARC (from 0.01 to 0.57W/g), whereas SF additions (0.30W/g) retarded staling with respect to soy flour bread (0.39W/g). Principal Component Analysis (PCA) of all the different treatments and formulations indicated that SMP addition resulted in the lowest firmness and least amylopectin retrogradation at the end of storage, likely due to the synergistic effect of soluble fibre, partly denatured soy proteins and lipid content of this ingredient.