Study On The Influences Of High Dietary Fiber On Fermentation And Baking Properties And Storage Characteristic Of Bread Dough

The study focused on partial replacement of wheat flour in breads with soybean dietary fiber (SDF), resistant starch (RS) and their mixtures at 20% and 30% levels. The influences of high-fiber on dough and baking performances of bread were investigated, and the process optimization was also studied in this paper.SDF and RS, whose dietary fiber content are 64.59% and 60% respectively, are natural, safe and high quality DF resources. Both of them, with high water holding capacity, gelatinization temperature and enthalpy, can be used as good food additive in bakery foods.Mixolab, F3 rheofermentometer, dynamic rheometer, and scanning electron microscope (SEM) were used to analyze the effects of high dietary fiber on the thermomechanical, rheofermented and dynamic rheological properties and microstructure of doughs. The addition of SDF and RS increased water absorption (increasing 43.3-63.3% and 5-7.6%, respectively), decreased C5-C4, inhibited the retrogradation of starch. SDF and RS had different influences on C1-C2 and stabilization time of dough. RS increased C1-C2 by 24.14-27.59% and decreased the stabilization time (53.52-66.46% of control), while SDF played active roles. Supplement with SDF and RS diluted the gluten network and reduced the values of Hm, Tx and R, having negative effects on gas holding ability and processing characteristics.Based on the baking performances and nutritive peculiarity analysis, it was found that SDF acted in synergy with RS, which not only increased dietary fiber and protein content, improved the effects of SDF alone on bread texture and flavor, but also enhanced the moisture content of breads only containing RS, and improved the bread yield. Compared with the commercial whole wheat bread, when bread nutrition, colour, and texture were all together concerned, the favorable products of high-fiber breads could be obtained under conditions of 5%SDF-15%RS, 10%SDF-10%RS and 7.5%SDF-22.5%RS, with higher quality and better mouthfeel.The effects of high dietary fiber on the changes of firmness, moisture migration and retrogradation of amylopectin of breads during storage were investigated by using texture analyzer, nuclear magnetic resonance (NMR) and differential scanning calorimetry (DSC) in this paper. The firming kinetic changes of bread showed that SDF and RS could improve the water binding capacity of bread, combine with starch of dough to form more stable compounds which enhanced the moisture retention capacity and lower the value of k (rate constant of bread aging), effectly delaying the increase of bread hardness during storage. The results of NMR and DSC indicated that SDF and RS reduced water activity and the rate of water loss, slowed amylopectin retrogradation process and bread aging, thus prolonged the shelf life of bread.According to the impacts of SDF and RS on the dough and bread system, choosed wheat gluten, transglutaminase (TG), pentosanase andα-amylase to improve the high dietary fiber dough (10%SDF-10%RS) by response surface method. The optimal dosage of four factorswere: wheat gluten 2.89%, TG 0.25%, pentosanase 34.76 mg/kg andα-amylase 20 mg/kg, under this condition, the specific volume and hardness of bread were 5.10 mL/g and 410.91 g.Through above experiments found that the bread supplemented with SDF and RS in combination had a high overall sensory acceptability and good texture retention, could well meet consumer requirements for high quality food (high dietary fiber, soft, white crumb, lower starch hydrolysis rate and low-calorie, etc)...