Effect of pregelatinized corn and rice flour on specific volume of gluten-free traditional Algerian bread KhobzEddar using central composite design

In the present study, the effect of addition of pregelatinized corn and rice flour on specific volume of gluten-free traditional Algerian bread Khobz Eddar was studied. The gluten-free breads were made from corn and rice/field bean formula in ratio 2/1 (w/w) and pregelatinized corn and rice flour were made by adding water to flour on the basis of 5/1 (w/w) and heated until 65°C. Response Surface Methodology (RSM) was used to optimize the gluten-free Khobz Eddar bread with the specific volume as the only response. The effect of hydration and pregelatinized corn and  rice flour on specific volume of the two formula of gluten-free Khobz Eddar bread was studied. The optimum points were characterized by specific volume and image analysis as compared to a control bread based on durum wheat semolina. The optimum formulation for corn/field bean bread contained 115 g/100 g of water and 7.05 g of pregelatinzed corn (dry basic) with a specific volume of 2.39 cm3/g and for rice/field bean bread the optimum was found by addition of 105 g/100 g of water and 6.3 g of pregelatinized rice (dry basic) with a specific volume of 2.24 cm3/g. Specific volume of corn/field bean bread showed a higher value as compared to rice/field bean bread (p<0.05), for both breads, the specific volume was lower (p<0.05) than control wheat bread (3.64 cm3/g). The image analysis  by software Image J showed that the number of cells in both formula was greater than that of Khobz Eddar control bread.   Key words: Gluten-free Khobz Eddar, optimization, pregelatinized flour, rice, corn, specific volume.