OPTIMIZATION OF SOLUBLE DIETARY FIBER EXTRACTION FROM DEFATTED RICE BRAN USING RESPONSE SURFACE METHODOLOGY

Optimum extraction conditions for extraction of soluble rice bran fiber (SRBF) from defatted rice bran (DRB) were determined using response surface methodology (RSM). The three independent variables for extracting SRBF, including ratio of Ca(OH)(2) solution to DRB, concentration of Ca(OH)(2) and extraction temperature on the yield of SRBF were determined on the basis of single factor experiments. A Box-Behnken design (BBD) was used to investigate the effects of the three independent variables, and the BBD consisted of 15 experimental points with three replications at the center point. The experimental study examined the effect of the independent variables within the following ranges: Ca(OH)(2) solution to DRB ratio range of 25:1-30:1, Ca(OH)(2) concentration in the range of 2-3% and the temperature in the range of 20-100C The optimum experimental yield of SRBF (7.86 +/- 0.04%) was obtained at the extraction condition of 3% Ca(OH)(2) solution with a ratio of solution to DRB of 29.75:1 (mL/g) stirred for 1 h at 84C. The experimental yield percentage was in agreement with predicted yield percentage of SRBF by RSM at the optimum extraction conditions.