Investigations into the properties of emulsifiers in yeast-leavened dough by means of infrared spectroscopy II. Experiments on the interaction of emulsifiers with starch and flour and in dough

High-resolution infrared (IR) spectra of emulsifiers for yeast-leavened bread were measured together with those of the individual components of wheat flour. Using the IR reflection technique, the entire dough was also investigated to give an insight into the development of structures in dough. The emulsifiers react with different components of wheat flour in a specific way. Using IR spectroscopy exact data for the strength of bonding and the kind of bonding between emulsifier and dough component can be obtained.

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Infrarotspektroskopische Untersuchungen zur Wirkung von Emulgatoren in Hefebackwaren. II. Versuche zur Wirkung von Emulgatoren auf Stärke, Mehl und im Teig

Zusammenfassung Emulgatoren, Weizenmehlinhaltsstoffe und Hefeteig wurden mit FT-IR-Spektroskopie in Transmission bzw. Reflexion gemessen. Es konnte anhand der Verschiebung der Carbonylabsorption gezeigt werden, wie verschiedene Emulgatoren mit unterschiedlichen Substraten in Wechselwirkung treten, so daß ihre Wirkung spezifisch ist. Die Wirksamkeit einzelner Emulgatoren kann mittels IR-Spektroskopie parametrisiert werden.

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Part I: Ref. [4]     

不同特性乳化剂对面团流变学性质的影响

对添加硬脂酰乳酸钠(SSL)、甘油单硬脂酸酯(DMG)、聚氧乙烯(20)失水山梨醇单硬脂酸酯(polysorbate60)的面团流变学特性进行研究,结果显示,虽然基本脂肪酸组成相同,但3种乳化剂对面团形成时间、面团稳定性、面团弱化度、抗拉伸强度等基本性质的影响有很大差异.高质量分数的DMG对面团有弱化倾向,添加polysorbate60可以得到面团形成的时间最长和最好的面团稳定性;添加SSL和polysorbate60对面团抗拉伸强度有不同程度的提高,而且SSL在较长的面团混揉时间能起到最好作用.不同剂量的乳化剂对面团流变学性质的影响也不相同.     

EFFECT OF EMULSIFIERS AND FUNGAL α-AMYLASE ON RHEOLOGICAL CHARACTERISTICS OF WHEAT DOUGH AND QUALITY OF FLAT BREAD

Teftoon, a flat bread made of whole wheat flour, is prepared by hand sheeting of dough, followed by baking. Different emulsifiers, like lecithin, E471 (distilled monoglyceride) and E472 (diacetylated tartaric acid esters of mono- and digelycerid of fatty acids), were added to the flour at various levels ranging between 0.25 and 1.0% w/w, and it was observed that they improved the dough characteristics. Improvement in bread quality parameters, such as force to tear and sensory acceptability, were monitored. Fungal α -amylase was also incorporated into the flour at 5–20 g/100 kg flour basis alone and in combination with the emulsifier. The force required to tear the fresh bread was decreased with emulsifier and enzyme addition; however, E472 addition at 0.75% w/w of whole wheat flour gave the softest bread. The tear force of stored bread significantly increased with storage; however, bread containing E472 showed a less increase in tear force up to a period of 3 days. The sensory acceptability was found to be higher than that of the control bread for emulsifiers, and lower for enzyme at a concentration higher than 10 g/kg flour.

PRACTICAL APPLICATIONS

Flat bread is normally consumed fresh, but the staling phenomenon starts immediately after baking this kind of bread. Today, large-scale production and increased consumer demands for high-quality bread with long shelf life have created the need for functional food additives such as emulsifiers and α -amylase enzyme. Incorporation of emulsifiers and enzyme decreased the hardness of Taftoon bread. Emulsifiers and α -amylase enzyme enhanced the flat bread dough quality. The sensory acceptability also improved with the addition of emulsifiers. Optimizing the amount of emulsifiers and enzyme required for reduction of bread hardness is vital because the quality and price of the final product depend on this parameter.     

小麦粉组成对面团水分迁移及制品品质影响的研究进展（网络首发、推荐阅读）

水分作为小麦粉面团中的主要组成部分,其含量、分布、存在状态对面团的加工特性、保藏性及制品品质稳定性具有重要影响。小麦粉由蛋白质、淀粉、脂肪、戊聚糖、矿物质等多种组分构成。小麦粉与水混合形成面团,在这一过程中面团会发生复杂的物理化学变化。面团中各种组分的成分结构和物理化学特性对这些变化产生较大影响,间接决定了制品的品质。因此了解面团混合过程中的不同组分与水结合后的变化,对制品的品质控制和质量提升具有重要意义。对近年来相关领域的研究成果进行了归类梳理,系统分析了小麦粉中不同组分之间以及与水分子的相互影响机制,讨论了小麦粉不同组分的吸水持水特性,解析了小麦粉的不同组分对水分分布迁移的影响,总结了决定面团水分迁移和影响制品品质的关键成分即蛋白质、淀粉、破损淀粉、戊聚糖等,并剖析它们决定产品质量的关键因素,以期进一步指导小麦粉制品的生产。     

几种乳化剂对小麦粉品质特性影响的研究

通过对乳化剂添加前后面团中蛋白质、淀粉性质、质构特性、微观结构等性质的比较,研究了乳化剂对小麦粉品质特性的影响.结果表明:乳化剂使得淀粉溶液碘蓝值、淀粉的溶解度和膨润力、静态提取麦胶蛋白和酸溶性麦谷蛋白含量、面皮的硬度和回复性降低,除单甘酯外,咀嚼性和凝胶性也降低,面筋交联度、弹性和黏着力增加;通过微观结构可以看出,乳化剂可与蛋白质相互结合形成大分子基团,使蛋白质的网络结构变得较为致密,并具有较好的立体感.     

基于主成分小米-小麦混合粉面团流变学特性综合评价

选择13个品种小米粉按照0~35%比例与小麦粉混合,通过对小米-小麦混合粉面团粉质特性和拉伸特性分析,基于主成分建立了混合粉面团流变学特性综合评价模型。结果表明,随着小米粉添加比例的增加,小米-小麦混合粉面团综合主成分值逐渐下降;主成分分析提取2个主成分,累计方差贡献率为85.21%;综合主成分值越高,小米-小麦混合粉面团流变学特性越好。豫谷18、白谷、冀谷19适宜制作高筋粉类食品;112和113综合主成分值最低,流变学特性较差,较适宜制作低筋类食品;当小米粉添加量超过15%时,除白谷、豫谷18这两个品种之外,其余品种综合主成分值均为负值,小米-小麦混合粉面团品质显著降低。     

复配型面包改良乳化剂的研究

借助粉质仪、流变仪等仪器设备研究了多种乳化剂对国产小麦粉烘烤品质的改良效果 ,最后得到一个应用于国产小麦粉的复配型面包改良乳化剂配方。该配方能显著改善面团流变学特性和面包品质 ,是一种高效、经济、实用的面包改良剂。     

Emulsifiers: Effects on Quality of Fibre-Enriched Wheat Bread

Resistant starch (RS) is a nutritional ingredient commonly used in bread products as dietary fibre (DF). This ingredient presents similar physiological functions than those imparted by DF, promoting beneficial effects such as the reduction of cholesterol and/or glucose levels on blood. Quality improvement of bread containing RS, with an optimized combination of emulsifiers, will be useful in the development of new and healthy bakery products. The objective of this research was to analyse the effects of different emulsifiers on several quality parameters of dough and bread prepared with wheat flour partially substituted with resistant starch as a dietary fibre. A blend of wheat flour/maize-resistant starch (MRS; 87.5:12.5) with sodium chloride, ascorbic acid, α-amylase, compressed yeast and water was utilized. Emulsifiers were incorporated to formulations in different levels according to a simplex centroid design. The viscoelastic, textural and extensional properties of dough were analysed. Bread quality was evaluated throughout the gelatinization and retrogradation of starch, specific volume of loaves, and texture and firmness of bread crumb. The incorporation of 12.5% (w/w) of MRS to wheat flour caused an increase of 5% in water absorption. Stability decreases markedly (from 9.9 to 2.2 min) and the mixing tolerance index increased (from 79 to 35 UF). The sodium stearoyl lactylate (SSL)–diacetyl tartaric acid esters of monoglycerides (DATEM) mixture increased hardness and resistance to extension on dough, whilst dough containing Polysorbate 80 (PS80) was softer; nevertheless, both types of dough retained less CO₂. An optimized concentration of the three emulsifiers (0.24% SSL, 0.18% PS80, 0.08% DATEM, w/w) was obtained by surface response methodology. The bread prepared with this combination of emulsifiers presented a considerable specific volume with a very soft crumb.     

Composition and Radical Scavenging Capacity of Phenolic Compounds in Wheat-Chickpea Dough

The content, composition, and radical scavenging capacity of phenolic compounds in wheat-chickpea (60:40, w/w) flour and dough were studied in this research. The content of phenolic compounds in wheat-chickpea dough was almost twice as high as in the flour from which the dough was made. The addition of chickpea flour to wheat flour contributed to the improved scavenging capacity of dough. The wheat-chickpea dough had a lower maximal achieved scavenging capacity than wheat-chickpea flour, but higher than that of the wheat dough. The quercetin, genkwanin, and apigenin glucosides could be considered as stable components during the mixing of the wheat-chickpea dough. The wheat-chickpea bread retained the radical scavenging capacity which the dough had.     

WATER ABSORPTION EFFECTS ON BIAXIAL EXTENSIONAL VISCOSITY OF WHEAT FLOUR DOUGH

Biaxial extensional viscosities of wheat flour dough at three water absorption levels were determined as a function of biaxial strain rates using lubricated squeezing flow. The shape of the curves obtained in this study showed a sharp increase followed by a gradual increase which could indicate the presence of viscoelastic effects, which is not the usual case reported in the published literature for other products when using this technique. Plasticizing effect of water coupled with the effect of the starch and the interaction among the other components of wheat flour dough could explain the rheological behavior of flour dough during lubricated squeezing flow testing. Values of biaxial extensional viscosities of wheat flour dough for the three water absorption levels obtained in this study showed significant differences in the entire deformation range (P < 0.05).     

Evaluation of l-ascorbic acid oxidation on SH concentration in soy-wheat composite dough during resting period

The effect of l-ascorbic acid (l-AA) on free sulfhydryl concentration (SH) was evaluated in soy-wheat composite dough from 100-500 (g/kg) soy flour substitution for wheat flour. Raw soy flour (RSF) and physically modified soy flours (PMSF1 and PMSF2) were used for the preparation of the composite dough with wheat flour. The two physically modified soy flours were prepared by steam flushing (PMSF2) and water boiling (PMSF1) of raw soy beans before flour preparation. Using a timer, dough blends were manually mixed (at approximately 60 rpm) to dough development time after which, dough was sampled for the estimation of free SH groups. l-AA (0.05% w/w) was mixed with the dough after dough development and the dough was sampled after 1 h of resting the dough. The results showed that l-AA (0.05% w/w) acted as a reducing agent by increasing SH levels in all soy-wheat dough blends (P<0.05). After 1 h of resting, soy-wheat composite dough without l-AA had lower concentrations of SH than that with l-AA. A positive correlation was shown between soy flour concentrations and SH concentration before and after dough resting. A negative correlation existed between l-AA consumption and SH concentration for RSF-wheat, PMSF1-wheat and PMSF2-wheat doughs. The results indicated that soy flour weakened wheat flour dough by increasing SH concentration and that l-AA could have a synergistic effect on the reduction of gluten proteins and thus weakening the dough.     

燕麦面团流变学及加工特性研究

以燕麦粉为原料,以中强筋小麦粉为对照,研究燕麦粉与小麦粉不同配比混合粉的面团流变学特性和食品加工特性.结果认为,与小麦粉相比,燕麦蛋白质组分中清蛋白、醇溶蛋白含量较低,球蛋白含量高,谷蛋白含量稍低.燕麦粉峰值、最大、最终黏度均小于对照小麦粉.加入燕麦粉后,面团形成时间延长,稳定时间降低.用淀粉代替燕麦粉,同样添加量下面包及馒头比容、总评分降低,面条吸水率、总评分降低,失落率升高.当面粉取代量大于5%时,对混粉食品制作品质有显著影响.加入10%、25%、10%燕麦粉制作面条、馒头和面包是较为理想的配比.     

Cooperation of phosphatidylcholine with endogenous lipids of wheat flour for an increase in dough volume

Phosphatidylcholine (PC) increases the gas-retaining ability of dough, the dough volume on fermentation and the loaf volume of bread. The cooperation of wheat flour endogenous lipids with PC was examined. More than 90% of the total wheat flour lipids were extracted with chloroform, the extracted lipids comprising glycolipids (33 wt%), non-polar lipids (56 wt%), and phospholipids (11 wt%). The increase in the specific volume of dough with delipidated wheat flour by the addition of PC was smaller than the increase in the specific volume of dough with native wheat flour. The addition of the extracted lipids to delipidated wheat flour restored the increase in dough volume by the addition of PC. The glycolipid fraction of the extracted lipids was most effective for enhancing the action of PC. The results suggest that interaction of PC with wheat flour glycolipids may synergistically increase foam stability to enhance the gas-retaining stability of dough.     

油脂对面团特性及微观结构的影响

在小麦粉中添加油脂,对面团流变学特性和微结构进行研究。结果表明：油脂对面团的形成时间、稳定时间、拉伸阻力等有不同程度的提高,同时可改善面团的流变学特性,提高面粉的品质;观察微观结构发现,添加油脂的面团中蛋白质颗粒明显增多,淀粉颗粒表面更加光滑。结合粉质实验和拉伸实验确定油脂在面粉中的最佳添加量为面粉质量的6%。     

不同品种紫薯粉面团品质特性

以纯小麦粉面团为对照,通过测定9种紫薯粉面团的粉质、糊化、流变学、水分分布状态特性,探讨9种紫薯粉对小麦粉混合面团品质特性的影响。结果表明:与纯小麦粉面团相比,不同品种紫薯粉面团的吸水率、稳定时间、弱化度、公差指数、糊化温度均有所增加;而面团带宽、峰值黏度、谷值黏度、最终黏度、衰减值、回生值均有所降低;储能模量、耗能模量和深层结合水基本呈现增加趋势,损耗角正切基本呈现下降趋势。紫薯粉的添加使得面团稳定性、保水性增加。不同紫薯粉平均粒径存在极显著性差异（P<0.01）,将紫薯粉平均粒径与其面团的粉质及糊化特性进行相关性分析和聚类分析,发现紫薯粉平均粒径与吸水率呈极显著正相关（P<0.01）,与稳定时间呈极显著负相关（P<0.01）;将紫薯粉面团分为三类,第I类包括鄂紫薯12号等7种紫薯粉面团;第Ⅱ类、第Ⅲ类分别为徐紫薯8号、绵紫薯9号。本研究为小麦粉面团专用紫薯粉品种的生产提供了理论依据。     

马铃薯全粉对比萨饼底加工工艺及品质的影响

研究马铃薯全粉对比萨面团流变学特性、发酵能力和比萨饼底质构特征、感官品质的影响。结果表明:马铃薯全粉能提高小麦粉的吸水率,缩短面团的形成时间,但会导致比萨面团的稳定时间缩短,弱化度增加;马铃薯全粉的添加量与面团的拉伸阻力、延伸度、最大拉伸比例和拉伸面积呈极显著负相关;马铃薯全粉能够提高面团的发酵能力和弹性,但会导致比萨饼底的硬度增加,感官品质略有下降,因此综合考虑确定马铃薯全粉的最佳添加量为15%;并进一步通过单因素和正交试验确定马铃薯比萨饼底的最佳原料配方为马铃薯全粉添加量15%、加水量60%、酵母添加量1.2%;在最佳原料配方的基础上确定马铃薯比萨的最佳工艺条件为醒发温度38℃、醒发湿度75%、醒发时间30 min、烘烤温度200℃、烘烤时间15 min,所得比萨的硬度为4 166.493 g,感官品质最佳。     

改性对玉米粉饼干品质影响的研究

利用快速粘度分析仪（RVA）,对玉米饼干专用粉的峰值粘度等指标进行了测定,并且通过物性分析仪对面团以及玉米粉饼干的质构特性进行了分析。分别比较了玉米饼干专用粉与玉米粉、低筋小麦粉的各个指标的差异,客观地分析了改性对玉米粉饼干品质的影响。试验结果表明,与普通玉米粉相比,改性实现了玉米粉的成团及玉米粉饼干的成型,且制作的玉米粉饼干的硬度、脆性适中。但是,与低筋小麦粉相比玉米饼干专用粉还存在一些不足,其硬度、脆性以及糊化特性等品质特性略差。     

小麦内源蛋白水解酶对面团流变学特性的影响

通过小麦内源蛋白水解酶对小麦粉面团流变特性影响的研究,结果表明小麦蛋白水解酶对面团流变强度上有显著的弱化作用,但对不同品种小麦粉的作用程度差异较大。在用乳酸调成的ＰＨ４环境下,小麦蛋白水解酶对面团的软化作用非常迅速。小麦内源蛋白水解酶易热失活,抑胃肽、ＮａＣｌ均能通过抑制小麦蛋白水解酶活力,有效抑制面团的软化作用。     

汽爆高粱全粉馒头的研制

目的:研究汽爆对高粱功能成分的影响以及汽爆高粱全粉添加量对面团和馒头质构特性的影响。方法:汽爆高粱以蒸汽为汽爆介质,研究0.8 MPa压力维压5 min的条件下高粱中功能成分的变化;将汽爆高粱全粉按不同比例添加到小麦面粉中制作馒头,用质构仪测定面团和馒头的质构特性,用白度仪测定馒头白度值,对馒头食用品质进行感官评价,并讨论了汽爆高粱全粉的适宜添加量。结果表明:高粱经汽爆处理后,高粱中的功能成分含量发生变化:不溶性膳食纤维和单宁含量明显下降,抗性淀粉、总多酚和总黄酮含量提高。添加适量的汽爆高粱全粉可改变小麦面团的特性及馒头的品质,在本实验中汽爆高粱全粉的适宜添加量为25%,此时硬化速率低,馒头的食用品质较好。结论:汽爆有利于降解不溶性膳食纤维和单宁含量,促进功能成分的溶出,抗性淀粉、总多酚和黄酮含量增加;汽爆高粱全粉可以添加到馒头中,可以为高粱的开发利用提供参考。     

Analysis of main physicochemical parameters in purple wheat with different milling technology

With layered milling flour technology, the efficiency of the nutrient distribution and hardness was demonstrated with the purple and normal wheat separation milling. The results showed that the total content on amino acid in purple wheat was 8.2–12.9% higher than the common wheat. Compared with the main nutriments Se, Fe, Ca between purple wheat and common wheat, the results showed that different milling methods treatment are capable of separating the different wheat flour from endosperms, bran, and aleurone layers. Micro and physicochemical characterization of different wheat flour and layers by means of microscopy techniques and images analysis provided relevant qualitative and quantitative information, which can be useful for the study of the microstructure of purple and normal wheat products and also for its processing and utilization.

Practical applications

Color wheat has gained more importance in the recent years due to its health benefits. Purple wheat is balanced in amino acid, mineral elements, and Wet gluten. Therefore, purple wheat is an excellent flour product source according to the Association of Official Agricultural Chemists (AOAC). Purple wheat rich in amino acid such as leucine, proline, serine, glycine, threonine, and glusate provide important roles in the quality and nutrient value of dough. Lately, the food industry has had a strong interest on purple wheat due to their benefits such as better delivery of protein components, and greater stability and functional performance. Using purple wheat as an ingredient in a flour product will not only improve the nutritional profile of the dough but will also substantially increase the natural microelement content. This study describes the development and characterization of flour product containing purple wheat.