Steamed leavened rice cakes made from rice Γour, sugar, water, yeast or baking powder were used to study the e β ects of ingredients on cereal-based cakes. Volume expansion linearly correlates to amylopectin and negatively correlates to amylose content (r2 \ 0Γ84), with an optimum amylose/amylopectin ratio of approximately 1 : 8. Higher amylopectin content resulted in sticky, elastic and unacceptable cake. The optimum water content for volume expansion was in the range of 90 ^5% by weight of rice Γour. Sugar content correlates linearly with volume expansion and tenderness of chemically leavened rice cakes (CLRC) (r2 \ 0Γ99 and 0Γ92, respectively). Sugar content above 50% of rice Γour weight decreased volume and softness of yeast-leavened rice cakes (YLRC). Tenderness of YLRC correlates linearly to fat content (r2 \ 0Γ98), but volume expansions correlates negatively to the square root of fat content (r2 \ 0Γ81 and 0Γ97 for the two rice cakes). Both tenderness (r2 [ 0Γ92) and volume expansion (r2 [ 0Γ93) correlates linearly with emulsiΓer content up to 3% by weight of rice Γour, above which the cake becomes crumbly. A little salt increased hardness, but further increase reduced both volume expansion and hardness of rice cakes. Skimmed milk powder greatly increased the expansion of CLRC. Ovalbumin content correlates linearly to volume expansion of YLRC (r2 \ 0Γ87) but negatively to the expansion of CLRC (r2 \ 0Γ96). The proteins that improved the textures of rice cakes were skimmed milk and egg white with an optimum content of 2Γ4%. Egg yolk, soya protein, whey powder and wheat gluten reduced both tenderness and volume expansion. The e β ects of the various ingredients interacting together were studied and the optimum formulations was determined using a Random Centroid Optimisation Program.
1998 SCI.