| In sponge dough bread processing, the sponge fermentation stage plays an important role in determining dough and final bread quality. Sponges were fermented for varying length of time with different amounts of malt and yeast, and doughs made from these sponges were studied for rheological properties by using the farinograph, mixograph, extensigraph, spread test and falling number. These sponges and doughs were also studied for pH, TTA and gassing power.;Yeasted sponge samples and unyeasted dough samples showed higher spread ratios in sponge and dough series. Tightening effect due to yeast and slackening effect due to malt were more evident when longer sponge fermentation times were used.;Response surface methodology technique was used to find the effect of sponge fermentation time, yeast concentration, water absorption, mixing time and potassium bromate on bread quality in terms of specific volume and grain score. These results gave us different combinations of the above 5 variables to obtain better quality bread. In short, we found that to get high SV, we need low water absorption, high yeast concentration, medium level of bromate, and long sponge fermentation time. But when higher water absorption is used, we need lower levels of bromate, higher yeast concentration, and shorter sponge fermentation times. Grain score is another important quality factor in bread, RSM studies showed that to get high GS at low water absorption we need high levels of bromate, high yeast concentration and shorter sponge fermentation time.;Farinograph and mixograph data showed longer sponge fermentation lowered the mixing time and viscosity. Effects of malt and yeast in lowering mixing time and viscosity were more noticeable when shorter sponge fermentation times were used. Extensigraph data showed resistance to extension decreased with increase in yeast, malt and sponge fermentation time. Unyeasted doughs showed higher extensibility values with longer sponge fermentation times. Sponge fermentation was found to be better correlated with extensigraph resistance to extension than to extensibility. Gasograph results showed that the amount of gas produced was dependent on sponge fermentation time, yeast concentration and malt content. All these factors were interrelated in determining the final gas production in bread. |
