【作者】 王晓艳；

【导师】 黄卫宁；

【作者基本信息】 江南大学 ， 食品科学， 2012， 硕士

【摘要】 本论文主要研究了大豆纤维粉(Soybean dietary fiber,SDF)和抗性淀粉(Resistant starch,RS)及其混合物以20%、30%比例部分替代小麦粉在面包中的应用,分析了高膳食纤维对面团特性及面包烘焙特性的影响,并进而对其进行了工艺优化研究。SDF与RS的膳食纤维含量分别为64.59%和60%,是天然、安全的优质膳食纤维来源。两者持水力、糊化温度和糊化焓值高,可作为良好的食品添加剂应用于烘焙食品之中。应用Mixolab混合实验仪、F3流变发酵测定仪、动态流变仪和扫描电镜(SEM),分别分析了高膳食纤维对面团热机械学、发酵流变学、动态流变学特性及面团微观结构的影响。结果表明,用抗性淀粉和大豆纤维粉部分代替小麦粉可提高面团吸水率(分别提高5-7.6%和43.3-63.3%),降低C5-C4值,对淀粉回生具有一定抑制作用。但两者对C1-C2值和面团稳定时间的影响不同,RS的存在会显著增大C1-C2值24.14-27.59%,加大蛋白质弱化度,降低面团稳定时间(为空白组的53.52-66.46%),而SDF对此则具有积极作用。两种纤维粉的加入均会稀释面筋网络结构,降低面团发酵时的Hm、Tx和R值,对面团的发酵特性、持气能力和加工特性等产生消极影响。通过对面包烘焙特性和营养特性分析发现,RS与SDF共用时具有一定的协同作用,制作的高膳食纤维面包不仅膳食纤维与蛋白质含量高,能量显著降低,风味与质构较单独使用SDF有所改善,且提高了RS单独添加时的面包水分含量,提升产率。与市售的全麦面包相比,综合面包营养、色泽与质构而言, 5%SDF-15%RS、10%SDF-10%RS和7.5%SDF-22.5%RS组制作的高膳食纤维面包口感良好,品质最佳。采用质构仪(TA)、核磁共振成像(NMR)和差示扫描量热仪(DSC)分别测定高膳食纤维对面包贮存过程中的硬度、水分迁移和支链淀粉回生变化的影响。面包硬度变化动力学结果显示,SDF与RS可提高面包持水性,与面团中的淀粉结合形成较稳定的复合物,结合水的能力增强,降低面包硬化速率常数k,可有效延缓贮藏期间面包硬度的增加。NMR和DSC结果表明,SDF与RS可降低面包水分活度和面包心水分减少速率,延缓支链淀粉的回生进程,降低面包陈化速率,进而延长面包的保鲜期。根据引入膳食纤维对面团与面包体系的影响研究,选用谷朊粉、转谷氨酰胺酶(TG)、戊聚糖酶和α-淀粉酶对高膳食纤维面包面团体系(10%SDF-10%RS组)进行响应面优化改良。通过各因素对高纤维面包比容和硬度影响的整体分析,确定四因素的最优添加量为谷朊粉2.89%、TG 0.25%、戊聚糖酶34.76 mg/kg和α-淀粉酶20 mg/kg,此条件下面包比容为5.10 mL/g,硬度为410.91 g。通过上述实验发现,将SDF与RS复合添加制作的高膳食纤维面包具有较高的感官整体接受性和良好的质构保持性,可以良好地满足消费者对于高品质食品(高膳食纤维含量、柔软、面包心白、较低淀粉水解速率及低热量等)的要求。更多还原

【Abstract】 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)更多还原