Comparative quality analysis of gluten strength and the relationship with high molecular weight glutenin subunits of 6 Tunisian durum wheat genotypes

Six Tunisian durum wheat genotypes (4 landraces and 2 improved) were evaluated for protein content, gluten strength, rheological characteristics, and HMW-GS patterns using a LabChip system. Variance analysis identified genotypic variation. The landraces Azizi, Mahmoudi, Chili, and Arbi exhibited the highest protein concentrations and gluten contents, and best dough tenacity and extensibility values. The Mahmoudi and Chili varieties had the highest protein contents (17.06 and 17.32% dry mass, respectively). Arbi and Chili had the highest gluten contents (60.88 and 60.59%, respectively). Azizi, Mahmoudi, and Chili were characterized by higher dough tenacity, lower dough extensibility, and a greater alveograph configuration ratio P/L. The high molecular weight glutenin subunits 6+8 (Azizi and Mahmoudi) and 7+15 (Chili), coded by the Glu-B1 locus, improved gluten strength and viscoelastic dough properties. Calculated HMW to LMW-GS ratios were within a narrow range of 0.17–0.29. Some genotypes have potential to be used as parents in breeding programs.     

The influence of monoacylglycerol and L‐glutamic acid on the viscoelastic properties of wheat flour dough and sensory characteristics of French loaf product

BACKGROUND: The influence of monoacylglycerol Rimulsoft Super(V) and L ‐glutamic acid added to wheat flour dough was studied. Properties of the doughs were evaluated on the basis of chemical analysis and rheological measurements on a farinograph. Bakery products made from these doughs were subsequently subjected to sensory analyses. RESULTS: It was found that L ‐glutamic acid influenced the water absorption in dough more (50.0 g kg^?1; water absorption 56.6%) than monoacylglycerol Rimulsoft Super(V) (50.0 g kg^?1; water absorption 55.0%). Farinograph measurements showed that doughs with the addition of L ‐glutamic acid resembled flour containing high‐quality gluten, but dough with the addition of monoacylglycerol Rimulsoft Super(V) corresponded to ‘weak’ flour. Sensory analyses revealed that, in comparison with the control sample of French loaf, the saliva‐absorbing capacity increased in the French loaf with the highest addition of L ‐glutamic acid (30.0 g kg^?1). Deterioration in quality and texture in French loaf with addition of L ‐glutamic acid (8.0 g kg^?1, 30.0 g kg^?1) was noted. No other statistically significant differences were found. CONCLUSION: It is acceptable to add both additives to dough in order to modify its rheological properties. Copyright © 2010 Society of Chemical Industry     

Effect of Extruded Wheat Germ on Dough Rheology and Bread Quality

Wheat germ, a by-product of the milling industry, has interesting nutritional properties. However, it has limited use due to a high risk of rancidity, which could be reduced by using certain thermal treatments such as extrusion. The aim of this study was to investigate how wheat germ extrusion affects the changes induced by its addition to bread dough. For this purpose, different quantities of extruded or raw wheat germ (2.5, 5, 7.5, 10, and 20?g/100?g flour) were added to bread dough. Rheological characteristics of the dough and final quality characteristics of the bread were analysed from both the physical and the sensory points of view. Wheat germ addition increased water absorption and development time but decreased stability after over-kneading, dough tenacity, extensibility, and dough alveographic strength. The addition of extruded wheat dough improved stability and decreased extensibility and strength. Bread made from dough with added wheat germ presented decreased volume, cohesiveness, and elasticity and increased firmness. However, extrusion increased the volume of breads with added wheat germ and improver and decreased firmness. All breads obtained positive acceptability scores in sensory analysis, although wheat germ addition (10?g/100?g flour) slightly decreased texture, appearance, and overall acceptability scores of breads. Germ extrusion therefore improves dough rheology and bread quality and constitutes a suitable treatment to stabilise wheat germ in bread dough.     

影响冷冻面团的因素及其品质改良研究进展

冷冻面团技术因具有延长货架期、防止老化、便于冷藏和运输等优越性,在国内外食品工业得到了广泛的应用。然而,冷冻面团的生产和储存也会面临诸多困难,例如酵母活性降低、面筋结构破坏和冰晶形成等,这些都会破坏冷冻面团的质量。本文概括总结了影响冷冻面团品质因素的作用机理及研究现状,并总结了提高酵母耐冻性、改善面筋结构和面团特性的有效方法。添加改良剂可以减小由于冻藏或冻融循环致使面筋网络破坏的程度,添加谷氨酰胺转氨酶可改善冷冻面团的粘弹性与面筋网络结构,还可明显增加冷冻面团面包的比容,减小面包芯的硬度。选用优质酵母可提高酵母在冷冻期间的发酵力,改善冷冻面制品的风味和口感,其中高产胞外多糖的乳酸菌可以有效改善冷冻馒头面团品质。冷冻面团技术推动了我国馒头、包子、饺子、月饼等中式面食制品快速发展,具有一定的发展潜力。     

兰州拉面专用粉对春小麦品质的要求——Ⅱ小麦籽粒面筋蛋白组成含量与品质的关系

共选用30份春小麦材料,参照Singh等[1]和Verbruggen等[2]方法,提取出不同材料的面筋蛋白、高分子量麦谷蛋白亚基(HMW-GS)和低分子量麦谷蛋白亚基(LMW-GS)。通过测定各蛋白组分的含量及比例,同时结合不同材料的理化品质、面团流变学特性以及拉面食用品质进行多元相关分析,结果表明:麦谷蛋白含量与小麦籽粒蛋白含量、湿面筋含量、面筋指数、干面筋含量呈显著正相关;与面团弹性、延伸性以及面团筋力也呈显著正相关;与拉面食用韧性、粘性以及总评分呈显著正相关。HMW-GS含量与小麦湿面筋和干面筋含量呈显著正相关;与面筋指数呈显著负相关。在面团品质方面,HMW-GS含量与面团韧性呈显著正相关,而与LMW-GS与面团延伸性和面团筋力为显著正相关。HMW-GS含量与拉面最终评分呈显著负相关,相反LMW-GS与拉面最终评分呈显著正相关。     

Effects of trypsin‐hydrolyzed wheat gluten peptide on wheat flour dough

BACKGROUND: Gluten peptide was prepared by trypsin hydrolysis and characterized by high‐performance liquid chromatographic analysis. The effects on non‐frozen and frozen doughs of trypsin‐hydrolyzed gluten peptide (THGP) and its combination with ascorbic acid or KBrO₃ were investigated. RESULTS: Molecular analysis of THGP showed a decrease in the high‐molecular‐weight and an increase in the low‐molecular‐weight sodium dodecyl sulfate‐soluble fractions, compared with those of control wheat gluten. The addition of 8% THGP decreased the mixing time and tolerance of the dough, both with and without ascorbic acid or KBrO₃. However, the maximum resistance and extensibility of the rested dough containing 8% THGP, with and without ascorbic acid or KBrO₃, were not significantly different from those of the control dough. The addition of 8% THGP significantly increased the loaf volume of bread baked from non‐frozen dough when combined with 60 ppm ascorbic acid or 30 ppm KBrO₃, but it had a significant effect both with and without ascorbic acid or KBrO₃ on frozen‐dough bread. A large difference in volume was observed between breads made with and without THGP at the oven‐spring, rather than at proofing. CONCLUSION: The addition of 8% THGP increased the loaf volume of bread made from freeze‐damaged dough and this effect increased when THGP was combined with 60 ppm ascorbic acid. Copyright © 2008 Society of Chemical Industry     

Influence of Buckwheat Flour and Carboxymethyl Cellulose on Rheological Behaviour and Baking Performance of Gluten-Free Cookie Dough

In the present study, the influence of buckwheat flour and carboxymethyl cellulose (CMC) on the production of sheetable gluten-free cookie dough of acceptable rheological properties and subsequently their effect on the quality of gluten-free cookies was studied. The buckwheat flour was used to replace 10, 20 and 30 % of rice flour in gluten-free formulations. Cookie doughs of 100 % rice flour and 100 % wheat flour served as control samples. The impact of CMC addition was examined on formulation containing 20 % of buckwheat flour. Oscillatory and creep measurements were applied to test the effect of buckwheat flour and CMC on the viscoelasticity of gluten-free cookie dough. Frequency sweep results showed that all samples had solid elastic-like characteristics. An increase in the buckwheat flour addition led to a decrease in storage modulus and zero shear viscosity and an increase in tan δ and maximum creep compliance, while the addition of CMC led to an increase in dough tenacity and resistance to deformation. Cookie dough containing 30 % of buckwheat flour expressed the highest viscous properties, as revealed by relative viscous compliance value. The gluten-free dough containing CMC and buckwheat flour between 20 and 30 % replacement level showed similar strength and extensibility as wheat cookie dough. The results of the physical and sensory evaluation of gluten-free cookies showed that buckwheat addition led to a decrease in cookie hardness and fracturability and an increase in eccentricity (deformation from regular shape) as well as the overall acceptability, as evaluated by untrained panellists.     

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。     

D-Erythroascorbic Acid in Bakers'Yeast and Effects on Wheat Dough

Extraction of hydrated and freeze-dried bakers’yeast yielded ～ 50 μg erythroascorbic acid (EAA) and 5 μg ascorbic acid (AA)/g dry yeast as determined by HPLC with electrochemical detection. D-EAA (82 ppm based on flour) slightly increased the flow of dough as rest time increased. Gluten isolated from a flour-water dough containing 82 ppm D-EAA or 100 ppm Lcysteine stretched at a faster rate than control gluten. EAA like AA did not change dough development time. Unlike AA, EAA showed neither oxidizing effect on dough and gluten nor improving effects on bread.     

Soybean Flour Lipoxygenase Isozymes Effects on Wheat Flour Dough Rheological and Breadmaking Properties

The effects of soy flour from LOX null mutant isolines and purified LOX isozymes on the rheological and breadmaking properties of a commercial hard wheat flour were investigated. Wheat flours were fortified with either 3% soy mutant flours alone, or in the presence of 0.2% and 1% linoleic acid. Purified LOX 2 isozyme had the greatest effect among LOX isozymes on dough extensibility and strength. Linoleic acid substrate addition reduced dough extensibility and strength. The L2L3 null isoline mutant for L1 resulted in the largest increase in bread volume. A reduction in bread firmness occurred after 5 day storage for all three single null mutant-containing samples in the presence of 1.0% linoleic acid substrate.     

Rheological properties and baking quality of commercial durum wheat meals used to make flat crispy bread

Four commercial semolinas and four low-grade semolinas (LGS) samples were used in this study to make flat crispy bread (Carasau). The meals, doughs, and bread were compared with respect to a set of physical, chemical, and textural characteristics, and the bread evaluated by a trained sensory panel. LGSs had a higher extraction rate (higher ash content), finer granularity, and a higher damaged starch content than semolinas. The study revealed the key role of dry gluten content in determining hydration capacity of the dough, whereas damaged starch affected water absorption only in semolina samples. Gluten index and the ratio of gluten tenacity to extensibility (alveograph P/L) were significantly correlated with the weight of the dough discs following sheeting and molding. The panelists gave the highest quality score to the bread with the highest values of crackling and hardness. Textural and sensory attributes were both correlated with one another, and with gluten strength and tenacity, but not with the gluten content of the meal, which only affected final moisture content of the bread. Meal samples with a more tenacious and elastic gluten were more suited to produce flat crispy breads. The yellowness of durum wheat bread could not be predicted by measuring the color of the meal with a reflectance method.     

黄秋葵全粉对小麦面团流变学特性的影响

为了探究黄秋葵全粉对小麦面团流变学特性的影响,采用Mixolab混合实验仪、吹泡仪、流变发酵仪以及旋转流变仪等技术手段研究了混合粉（黄秋葵全粉添加量为0、1%、3%、5%、7%、9%）面团的热机械学特性、吹泡特性、流变发酵特性以及动态流变学特性。结果表明,随黄秋葵全粉添加量的增加,混合粉湿面筋含量降低,减少幅度达79.96%;面团的吸水率由63.30%增加到65.90%,形成时间和稳定时间先下降后上升,蛋白质弱化度增强;面团的蒸煮稳定性没有发生变化,但糊化峰值粘度下降,回生值减小;面团的韧性、延展性以及发酵性能下降,最大发酵高度Hm值下降了39.80%。此外,面团的储能模量G'和损耗模量G'均显著增加（P<0.05）,且G'增加占主导地位。综上所述,黄秋葵全粉的添加显著改变了小麦面团的流变学特性,且各添加量下混合粉面团的流变学特性指标有差异。研究结果为黄秋葵复合面制品的开发提供了理论依据。     

变性淀粉对面团流变学特性和面包品质的影响

探讨不同添加量的马铃薯变性淀粉和木薯变性淀粉对面团流变学特性和面包品质的影响。结果表明:两种变性淀粉均可改善面团的流变学特性,增大面团的韧性、减小面团的延伸性,改善面团的筋力;与对照相比,马铃薯变性淀粉能有效改善面包的焙烤品质,明显增加面包的比容,有效改善面包的硬度和弹性,木薯变性淀粉对面包品质的影响不明显;马铃薯变性淀粉的最适添加量为0.8%～1.2%面粉。     

Functional effects of xanthan gum on composite cassava-wheat dough and bread

The use of composite flour for bread making is gradually gaining prominence worldwide due to some economic and nutritional reasons. However, studies on the application of functional ingredients purposely to improve composite bread quality are very few. This paper examines the functional role of xanthan gum (XG) on the properties of dough and bread from composite cassava-wheat flour. The viscoelastic properties of dough and gas retention characteristics of batter as well as the fresh and storage properties of bread from the composite flour (90% wheat plus 10% cassava) were studied. The crumb cell structure was also studied using digital image analysis technique. Inclusion of XG had significant effects on the dough tenacity and extensibility and sensory acceptability of fresh composite bread. The oven spring, specific volumes of bread loaf and crumb softness were higher at 1% XG content. Also, addition of XG made the composite bread samples had more open crumb structure and better sensory acceptability. However, moisture loss and crumb firming during bread storage were best reduced when 1% XG was added to bread formulation.     

Wet separation of wheat flours into starch and gluten fractions: the combined effects of water to flour ratio–dough maturation time and the effects of flour aging and ascorbic acid addition

The process of making a dough, allowing time for maturation, dispersing the dough in water and wet sieving/washing to obtain a protein fraction and starch milk was studied using response surface methodology by changing the water to flour ratio in dough making (400–710 g kg^?1), maturation time (45–660 s) and the type of flour. Two grades of bread wheat flour and durum clear flour were studied. The effects of aging at ambient temperature for up to 29 days and the addition of ascorbic acid at 100 or 500 mg kg^?1 flour on separation behaviour were also studied for freshly milled high‐grade (65% extraction) bread wheat flours at constant maturation time, 600 s, and at optimum farinograph water absorption value. The quantities and dry matter contents of the protein fraction and starch milk were measured; a sample of starch milk was centrifuged to obtain decantate, tailings and prime starch fractions, and the dry matter contents of each were determined. All the dried samples were also analysed for protein content. The fractional recoveries of dry matter and protein in the protein fraction, prime starch, tailings and decantate were calculated for each experiment. The acid values of flour oils were also determined on some aged flour samples. The results indicated superior separation characteristics in high‐grade wheat flour compared with lower‐grade flours. The water to flour ratio was more influential than maturation time within the range studied. Contrary to the initial expectation, no statistically significant effect of flour aging was observed in the studies with no additive, and ascorbic acid addition was not found to improve the wet separation behaviour, the separation behaviour becoming even worse at the 100 mg kg^?1 level. Acid value showed a slight increase with time. © 2002 Society of Chemical Industry     

酵母对青麦油条面团发酵特性及其品质的影响

以无铝油条预混粉及青麦粉制作青麦油条,采用发酵仪和流变仪对不同种类酵母（H-1即发干酵母（Saccharomyces cerevisiae var. ellipsoideus,耐高糖,简称H-1）、H-2即发高活性干酵母（Saccharomyces cerevisiae var. boulardii CNCM I-3799,耐高糖,简称H-2）、L-1高活性干酵母（Saccharomyces cerevisiae var. willanus,低糖,简称L-1）、L-2即发干酵母（Saccharomyces cerevisiae var. bayanus EC-1118,低糖,简称L-2））,不同青麦粉添加量（0%、3%、6%、9%、12%）油条面团的发酵特性和流变特性进行研究,并对此面团制作成油条的比容、感官品质和质构特性进行分析。结果表明：4?种酵母中H-2酵母面团的发酵特性参数（产气量、持气率、面团开始漏气时间）最好,弹性模量与黏性模量较大,黏弹性较好;加入青麦粉后,H-2酵母制作的油条比容较大,感官评分较高,硬度、咀嚼性较小,弹性较大;在青麦粉添加量为6%制作油条时,油条比容和质构指标适中,感官评分与普通油条相差不大,碳水化合物及膳食纤维含量较高。因此,选择H-2即发高活性干酵母发酵、添加6%青麦粉制作的油条品质较好,营养丰富。     

紫淮山全粉对面团流变特性及面条质构特性的影响

研究不同紫淮山全粉添加量对面粉粉质特性、糊化特性、面团拉伸特性和面条品质的影响。结果表明,随着紫淮山全粉添加量的增加,面粉的吸水率上升。面团的形成时间在添加量为15%时达到最大值,为5.3 min,增加了39.5%。面团稳定时间在添加量为10%时达到最小值,为3.5 min,减少了40.7%。紫淮山全粉的添加使拉伸能量、延伸度下降。面团在45、90、135 min醒发时间下的延伸度均在添加量为25%时达到最小值。添加紫淮山全粉能降低糊化温度、面粉黏度和回生值,且最终黏度和回生值均在添加量为25%时达到最小值,但崩解值在添加量为25%时达到最大值。面条的硬度、胶黏性、咀嚼性、回复性均在紫淮山全粉的添加量为15%时达到最大值,但紫淮山全粉的添加对面条的弹性无显著性(p>0.05)影响。面条的L*值随紫淮山全粉添加量的增加呈显著(p<0.05)下降趋势,添加量低于15%时,紫淮山面条的感官评分较高。紫淮山全粉对面粉粉质特性、糊化特性、面团拉伸特性和面条感官品质均有较大影响,紫淮山全粉的最高添加量以15%为宜。本研究结果可为紫淮山全粉的应用提供理论参考。     

面粉中胚芽含量对面团流变学特性及馒头品质的影响研究

在小麦面粉中添加同种小麦提取的胚芽所制成的胚芽粉,测定其面团流变学特性及降落数值,并做馒头感官评价试验。实验表明,拉伸面积、最大拉伸阻力、拉伸阻力、拉伸比例、稳定时间和粉质质量指数与胚芽添加量呈显著线性负相关;弱化度与胚芽添加量呈显著的线性正相关;降落数值、形成时间与胚芽添加量线的相关性不显著。在一定添加范围内(0～2%)馒头总评分随胚芽粉添加量增大而增大,超过此数值则馒头总评分随添加量增加而减小;馒头的麦香味也有此趋势。     

植物乳酸菌M616对发酵酸面团发酵特性的影响

本文研究了在酸面团发酵过程中,植物乳酸菌M616(Lactobacillus plantarum M616)对面团p H、TTA以及糖类含量变化的影响,并利用F3流变式发酵仪和吹泡仪对面团发酵力及流变特性的变化进行了研究。结果表明植物乳酸菌M616不仅对酵母菌的生长具有一定抑制作用,而且在面团p H和TTA的变化过程中起主导作用;另外,乳酸菌对淀粉的降解作用大于对还原糖的吸收,从而使面团中还原糖的含量增加,增加面团的甜味。在发酵后期,面团p H降低至3.73,这在一定程度上抑制了体系中霉菌和其它杂菌的生长。植物乳酸菌的生长代谢不仅显著提高了面团黏度、筋力,而且减缓了面团在发酵过程中韧性的降低。其中发酵酸面团对面团黏度和筋力影响最大,发酵过程中酸面团的最大黏度和筋力可以达到酵母发酵面团的2倍。     

Cooking behaviour and acceptability of composite pasta made of semolina and toasted or partially defatted soy flour

The effects of the replacement of increasing amounts of semolina with toasted or partially defatted soy flour on dough rheological indices and spaghetti quality were evaluated. The replacement caused the dough weakening and the increase of the tenacity-extensibility ratio. Due to the competition of soy proteins and starch for water, the substitution of increasing amounts of semolina was able to increase the optimal cooking time without significant changes of the ratio between the increase in weight or diameter and the weight or diameter of dry spaghetti (ΔP/P and ΔD/D) but with a significant slowing of the ΔL/L (ratio between the increase in length and the length of dry spaghetti) increase during overcooking. Around the optimal cooking time, the release of organic matter was higher in pasta made exclusively of semolina whereas the sensory response was similar for control and composite spaghetti. Statistically significant correlations were obtained between protein content of the flour mixtures or dough alveographic indices and the cooking behaviour of semolina-soy spaghetti according to non-linear regression models. In particular, both protein content and alveographic indices allowed to predict approximately 92-94% of the variation of cooking losses and, in a lower measure, the variation of bulkiness and elasticity of semolina-soy spaghetti.