The objectives of this work were to study the influence of sugar, starch and Hydroxypropylmethylcellulose (HPMC) concentrations on Porosity and textural properties of sponge cakes for optimization of formulation for low-sugar cake. Response surface methodology (RSM) was performed to examine the effects of independent variables on porosity and firmness and to determine the optimum level of ingredients . Independent variables selected for the study were: sugar concentration (0, 10 and 20 % w/w), HPMC concentration (0, 0.5 and 1 %w/w) and starch concentration (0, 5 and 10 %w/w). For each response, second order polynomial models were developed using multiple linear regression analysis. Analysis of variance was performed to check the adequacy and accuracy of the fitted models. The optimum values for sugar, HPMC and starch concentrations were found to be 10, 0.5, and 5 %, respectively. These levels of ingredients led to porosity and firmness values of 76.56 % and 13.00 N respectively. The microstructures of samples were also analyzed using scanning electron microscopy and it was found that SEM pictures confirmed the RSM results about the effects of ingredients on porosity. [ABSTRACT FROM AUTHOR]