3.1. Phytic acid extraction technique
Table 1, Table 2 and Table 3 present the effects of the variables and the response estimated by the model (Ŷ) for the IRGA 417 rice bran PA extraction. According to the regression coefficients ( Table 2), the variables X2 (concentration of HCl), X3 (temperature) and X4 (time) had a significant effect on the response (Y). These results were similar to those for soya PA extraction reported by Han (1988) and for extruded cotton and rice bran by Fuh and Chiang (2001). According to Kolchev (1978) the important variables for the production of rice bran phytin were a solid/liquid ratio of 1:5, a concentration of 0.1 M HCl and an extraction time of 2 h. There are few descriptions in the literature of the extraction of PA from grains for the purpose of purification, although many studies have been performed on extracting and quantifying the amount of PA.