EFFECTS OF INGREDIENTS ON THE CHARACTERISTICS OF RICE CAKES

Steamed leavened rice cakes made from rice flour, sugar, water, yeast or baking powder were used to study the effects of ingredients on cere al-based cakes. Volume expansion linearly correlates to amylopectin an d negatively correlates to amylose content (r(2) = 0.84), with an opti mum amylose/amylopectin ratio of approximately 1:8. Higher amylopectin content resulted in sticky, elastic and unacceptable cake, The optimu m water content for volume expansion was in the range of 90 +/- 5% by weight of rice flour, Sugar content correlates linearly with volume ex pansion and tenderness of chemically leavened rice cakes (CLRC) (r(2) = 0.99 and 0.92, respectively). Sugar content above 50% of rice flour weight decreased volume and softness of yeast-leavened rice cakes (YLR C). Tenderness of YLRC correlates linearly to fat content (r(2) = 0.98 ), but volume expansions correlates negatively to the square root of f at content (r(2) = 0.81 and 0.97 for the two rice cakes). Both tendern ess (r(2) > 0.92) and volume expansion (r(2) > 0.93) correlates linear ly with emulsifier content up to 3% by weight of rice flour, above whi ch the cake becomes crumbly. A little salt increased hardness, but fur ther increase reduced both volume expansion and hardness of rice cakes . Skimmed milk powder greatly increased the expansion of CLRC. Ovalbum in content correlates linearly to volume expansion of YLRC (r(2) = 0.8 7) but negatively to the expansion of CLRC (r(2) = 0.96). The proteins that improved the textures of rice cakes were skimmed milk and egg wh ite with an optimum content of 2-4%. Egg yolk, soya protein, whey powd er and wheat gluten reduced both tenderness and volume expansion. The effects of the various ingredients interacting together were studied a nd the optimum formulations was determined using a Random Centroid Opt imisation Program. (C) 1998 SCI.