Effects of Wheat Variety and Processing Conditions in Experimental Bread Baking Studied by Univariate and Multivariate Analyses

The effects of variety, mixing conditions and fermentation time on bread loaf characteristics were studied by univariate and multivariate statistical methods. Nearly all the measured bread loaf characteristics were significantly affected by variety, fermentation time, and mixing conditions. Significant interactions were also found. Multivariate analysis (principal component analysis; PCA), was used to find the main variation among the bread samples and to identify the bread loaf characteristics that contributed to describe this variation. The characteristics loaf volume and weight described a large part of the main variation among the loaves and these characteristics were studied in more detail by response surface methodology. The loaf volume and weight response surfaces for varieties, which by multivariate analysis were found to have common properties, followed similar general patterns. It was shown that the experimental design used provided information about the baking performance of wheat flours over a wide range of experimental conditions and, thus, can be a useful supplement to standardised and optimised baking tests.     

影响馒头品质的相关指标分析

为给优质馒头专用小麦的培育和馒头品质改良提供参考依据,以来源于北方冬麦区、黄淮冬麦区、西南冬麦区和长江中下游冬麦区的128个小麦品种(系)为材料,利用感官评价与质构仪测试相结合的方法,分析影响馒头品质的相关指标。结果表明,馒头感官品质中,除馒头的比容与色泽、结构、弹韧性、黏牙性和气味的相关性不显著外,其他指标间均为极显著正相关;馒头质构指标中,馒头的硬度与内聚性和咀嚼性分别呈极显著负相关和正相关;馒头质构指标中的黏附性、弹性、硬度和咀嚼性与馒头感官品质的相关指标显著相关,可以在一定程度上补充或矫正相关的感官评价分析。同时,筛选出感官品质较好的材料有中优9507、CMT-3T88和陕182等,质构指标较好的材料有扬00-126、新麦19和新春9号等,这些材料适合制作优质手工馒头;尤其是筛选出的感官品质和质构指标均较好的材料Kn3106、川麦107、新春9号和新麦19,可作为小麦优质资源加以利用。参试材料的面粉白度较低(平均值为73.83)且高白度材料较少;面粉白度高于80的小麦品种(系)仅有T21-6和武汉麦,这些材料可作为高白度小麦优质资源加以利用,有助于改良馒头的色泽品质。     

部分徐麦品种（系）馒头的挥发性物质和质构分析

为明确不同徐麦品种（系）馒头制品的挥发性物质和质构特征,本研究利用顶空固相微萃取(HS-SPME)技术结合气相色谱-质谱法(GC-MS)对5个徐麦品种（系）馒头制品的挥发性物质进行分析,并利用TMS-PRO质构仪进行了TPA检测。结果表明,馒头中挥发性成分有41种,包括醇类（1种）、醛类（2种）、酯类（13种）、烷类（10种）、烯类（4种）、苯类（8种）、酮类（2种）以及醚类（1种）化合物。含有挥发性物质种类最多的品种是徐麦178（29种）,最少的品种是徐麦39（22种）。TPA检测数据显示,徐麦178制作的馒头具有较高的硬度、弹性和粘性;徐麦39的质地较为柔软。不同品种（系）馒头因为挥发性物质间的相互作用、种类数、含量以及硬度、弹性和粘性等的不同具有了独特的风味和口感。     

Effects of Guar Galactomannan on Wheat Bread Microstructure and on theIn vitroandIn vivoDigestibility of Starch in Bread

Microscopy andin vitrodigestibility methods were used to obtain information about the putative inhibitory effect of guar gum, an endospermic seed extract, on the rate of digestion of wheat bread starch. Guar seed endosperm was examined by bright field microscopy after staining with toluidine blue or ruthenium red, by epifluorescence microscopy after labelling with two fluorescein-labelled lectins specific for α-D-galactose andD-mannose residues, respectively, and by scanning electron microscopy (SEM). These methods showed that guar galactomannan, the main component of guar gum, was located both within the plant cell walls and as amorphous deposits within the cell vacuole. SEM examination showed that the latter persisted in the milled guar flour. Examination of wheat bread containing guar gum by SEM and by fluorescence microscopy using the labelled lectins revealed that the starch granules and surrounding bread matrix were coated with a layer of galactomannan mucilage. After guar bread was ingested by pigs, the close association of galactomannan with the wheat starch persisted during the early post-prandial period (0–90 min), but this was greatly reduced at later post-prandial times (≥180 min). Thein vitrohydrolysis of starch in guar bread was found to be attenuated significantly compared with normal wheat bread. The results are consistent, therefore, with the concept that guar galactomannan acts as a physical ‘barrier’ toalpha-amylase–starch interactions and/or subsequent release of hydrolysed products (e.g. maltose). Such a process, in addition to the effect of guar gum on digesta viscosity, may be significant in reducing the rise in post-prandial glycaemia caused by guar gum in humans.     

基于上部叶片叶绿素荧光参数的小麦产量预测与评价

为了利用叶绿素荧光快速测定技术实时评价植株光合生产能力以及预测小麦籽粒产量,以豫麦49-198和郑麦9694为试验材料,设置0、90、180、270 kg·hm^-24个氮素水平,通过2014-2016年连续两个生长季的田间试验,在小麦主要生育阶段同步测定植株顶部四片完全展开叶的净光合速率（P_n）、叶绿素荧光参数及叶面积。结果表明,P_n和叶绿素荧光参数因生育时期、氮素水平和叶片位置的不同呈现规律性变化。叶绿素荧光参数F_m′、F_v′、F_v′/F_m′ 和 F_s与P_n 相关性较好,且相关系数（r）均随叶位的降低而降低,其中,F_m′与P_n的相关性最好。将叶面积与对应的净光合速率和叶绿素荧光参数组合出光合性状累积量指标,与P_n 相比,光合累积量与产量的相关性显著提高。组合顶部四片叶,光合累积量与产量相关性在灌浆前期表现最好（r=0.875）。光适应下荧光参数累积量与产量的相关性表明,顶部两片叶的相关性较单叶片或其他叶位组合均表现较好,相关系数在不同荧光参数、生育时期间差异均较大,以F_m′表现最好,其次是F_v′;生育期间比较,孕穗期至灌浆中期整体较好。总体而言,在灌浆前期,顶部两片叶的F_m′累积量能够较好地预测小麦籽粒产量,为小麦生长诊断和田间管理提供技术支持。     

利用无人机图像颜色与纹理特征数据在小麦生育前期对产量进行预测

为了实现基于无人机的小麦产量快速预测,通过不同种植密度、氮肥和品种的田间试验,应用无人机航拍获取小麦生育前期（越冬前期和拔节期）的RGB图像,通过图像处理获取小麦田间颜色和纹理特征指数,并在小麦收获后测定实际产量。通过分析不同颜色和纹理特征指数与小麦产量的关系,筛选出适合小麦产量预测的颜色和纹理特征指数,建立小麦产量预测模型并进行验证。结果表明,小麦生育前期图像颜色指数与产量的相关性较好,而纹理特征指数相关性较差。对越冬前期利用单一颜色指数NDI构建的产量预测模型验证时,R为0.541,RMSE为671.26 kg·hm^-2;对拔节期用单一颜色指数VARI构建的产量预测模型验证时,R为0.603,RMSE为639.78 kg·hm^-2,预测结果比较理想,但不是最优。对越冬前期颜色指数NDI和纹理特征指数ENT相结合构建的产量预测模型验证时,R和RMSE分别为0.629和611.82 kg·hm^-2,比单一颜色指数模型分别提升16.27%和减小8.85%;对拔节期颜色指数VARI和纹理特征指数COR相结合构建的产量预测模型验证时,R和RMSE分别为0.746和510.29 kg·hm^-2,较单一颜色指数模型分别提升23.71%和减小20.24%。上述结果说明,将无人机图像颜色和纹理特征指数相结合建立的估产模型精度较高,可在小麦生育前期对产量进行有效预测。     

Structure and Mechanics of Starch Bread

The mechanical properties of breads made of potato or wheat starch were measured in two successive compression/decompression cycles. From the shape of the stress–strain curves, the initial modulus and the critical stress and strain could be derived; the critical stress and strain are those at which the crumb structure starts to collapse. The magnitude of the stress–strain related parameters changed markedly during storage. The initial modulus, as well as the critical stress for structural collapse, increased, and the critical strain decreased. Moreover, the resistance of bread crumb to collapse of structure in compression decreased. The mechanical properties of potato starch bread changed more rapidly than those of wheat starch bread. The results are discussed in relation to the structure of the starch breads on different levels, i.e. from molecular (amylopectin recrystallisation) to macroscopic (sponge structure). It is concluded that the mechanical properties of the starch breads are determined by the mechanical properties of the condensed lamellae and beams consisting of irregularly shaped, partly swollen starch granules as well as by the distribution of the thickness of the lamellae and beams.     

新疆冬小麦品种品质性状与面包、馒头、面条加工品质的关系

为了给优质面包、馒头、面条专用品种选育提供品质辅助选择指标,以30份新疆冬小麦品种(包括自育品种和引进品种)为材料,分析了新疆冬小麦品种品质性状与面包、馒头、面条加工品质的关系.回归分析结果表明,小麦籽粒性状、面粉品质、面团特性、淀粉糊化特性以及面粉色泽对新疆冬小麦品种面包、馒头和面条加工品质均有显著影响;面粉灰分、湿面筋、稀懈值、亮度和红度是影响面包、馒头和面条加工品质的共同品质性状;形成时间、稳定时间、延展度是影响面包和面条加工品质的共同品质性状;而籽粒性状仅对新疆冬小麦品种馒头加工品质有显著影响.相关分析结果表明,千粒重、形成时间、稳定时间、拉伸面积、最大拉伸阻力、红度和黄度与面包总分呈显著相关关系,相关系数分别为0.460、0.516、0.537、0.719、0.707、0.534和-0.403;籽粒蛋白质含量、面粉蛋白含量和湿面筋含量与馒头总分呈显著相关关系,相关系数分别为-0.397、-0.458和-0.552,面团延展度、稀懈值与面条总分呈显著相关关系,相关系数分别为0.438和0.432.从以上结果可以看出,面包与面团流变学特性,馒头与蛋白质和面筋数量,面条与面团流变学特性及淀粉糊化特性的关系更为密切,这些品质性状可以作为新疆冬小麦品种面包、馒头、面条加工品质改良时的辅助选择指标.     

Instrumental Texture of White Salted Noodles Prepared from Recombinant Inbred Lines of Wheat Differing in the Three Granule Bound Starch Synthase (Waxy) Genes

Texture is a key quality determinant of white salted noodles (WSN). Recombinant inbred lines (RILs) (n=130) of wheat with all combinations of the three Waxy genes provided a unique opportunity to relate granule bound starch synthase (GBSS) gene dosage with the texture of WSN using texture profile analysis. Harder noodles tended to be more adhesive and chewier (r=−0·68 and 0·97, respectively), whereas a reduction in adhesiveness was correlated with greater cohesiveness (r=0·65), springiness (r=0·72), and resilience (r=0·66). Cohesiveness and resilience were highly correlated (r=0·94). Highly significant variation existed among the RILs for all noodle texture parameters. Normal starch RIL noodles tended to produce the hardest, most adhesive and chewy, but least cohesive, springy and resilient noodles. Full waxy RIL noodles were the softest, thickest, least adhesive and chewy, and most cohesive and springy. Partial waxy RIL noodles generally were intermediate in texture. The GBSS genotype comprised 27–68% of the variance of noodle texture compared to 27–60% variance for RILs within GBSS class. Based on these results, starch composition is a major contributor to the texture of white salted noodles.     

Interrelationships of Protein Composition, Protein Level, Baking Process and the Characteristics of Hearth Bread and Pan Bread

Baking performance of hearth bread and pan bread were investigated using 10 wheat varieties with variable protein quality. For most varieties, samples were selected at two protein levels, approximately 11 and 13% (d.m.). The effects of flour quality on loaf characteristics were different for hearth bread compared to pan bread, where both protein quality and protein content affect loaf volume positively in an optimised baking test. Hearth bread is more complex as both the form ratio and loaf volume are critical external characteristics. When using fixed proving time, the form ratio was positively affected by dough resistance and mixing peak time at high speed mixing, and negatively affected by dough extensibility. Dough resistance and mixing peak time correlated strongly to the HMW glutenin composition, whereas dough extensibility was related to protein content. In contrast to the form ratio, loaf volume was positively affected by dough extensibility, whereas protein quality had no significant effect. This was seen both for doughs produced at optimal mixing time at high speed mixing (126 rev/min) and for doughs produced at fixed mixing times at low speed mixing (63 rev/min). When proving time was optimised to achieve a defined form ratio, flours of strong protein quality should be proved longer than flours of week protein quality, resulting in higher loaf volume for flours of the strongest protein quality. With respect to protein content, the positive effect of protein content on loaf volume was counteracted due to reduced proving time when aiming for a defined form ratio.     

绿茶面包中儿茶素总量检测方法研究

儿茶素是茶叶的主要功能成分,本试验探讨了乙醇浸提、硫酸-香荚兰素比色法检测绿茶面包中儿茶素含量的可行性.选择95％乙醇溶液作为提取溶剂,采用3因素3水平正交试验设计方案,考察料液比、浸提温度、浸提时间对绿茶面包中儿茶素总量提取效果的影响,并对硫酸-香荚兰素比色法检测绿茶面包中儿茶素含量进行了方法学考察.结果表明,绿茶面包中儿茶素总量检测的最佳浸提条件为:料液比1:20(g·mL-1),70℃水浴浸提45 min;硫酸-香荚兰素比色方法为:取0.5 mL浸提液,加入2.5 mL1％的香荚兰素/乙醇溶液和2.5 mL30％的硫酸/乙醇溶液,在20℃下反应10～30 min,取反应液在500 nm处测定吸光度.本方法中儿茶素浓度在0.025～0.3 mg·mL-1范围内,吸光度与浓度线性关系良好(R2=0.9996),同一样品重复测定6次的RSD为1.31％,儿茶素高、中、低浓度加标回收率范围在98.75％～103.25％,本方法满足绿茶面包中儿茶素总量的检测分析,儿茶素含量可作为标定绿茶面包中茶叶添加量的评价指标.     

大豆膳食纤维在面包中的应用

文章研究了大豆膳食纤维在面包中的应用。添加大豆膳食纤维后,面粉的粉质特性发生了明显的改变:面团形成时间和稳定时间随着大豆膳食纤维添加量的增加先升高再降低,弱化度则是先下降再升高,而吸水率则是随着膳食纤维的添加量的增加一直升高;在面包中添加大豆膳食纤维在保持口感的基础上提高面包出品率,通过正交实验确定最佳配方为:面粉213.4 g、水119.8 g、白砂糖20 g、鸡蛋1个、黄油20 g、大豆膳食纤维6.6 g、食盐2 g、酵母2 g、面包改良剂3.3 g、谷朊粉2.2 g,能够提高7%左右出品率,并且使面包保持良好的口感和风味。     

Endosperm Texture in Wheat

One of the fundamental means of classifying wheat is through its endosperm texture. It impacts significantly on the milling process affecting among other things flour particle size and milling yield. Hardness in wheat is largely controlled by genetic factors but it can be affected by the environment and factors such as moisture, lipid, and pentosan content. The principal genetic locus controlling endosperm texture in wheat, Ha, is located on the chromosome 5D. At this locus several genes, notably the puroindolines, have been identified. Puroindolines are the major components of the 15 kDa protein band associated with starch granules that is more abundant in soft wheats than in hard. Recently the puroindolines have been shown to enhance grain hardness in rice. In this review we discuss the structure of hard and soft wheat endosperm with particular emphasis on when differences in endosperm texture can be detected in the developing seed. The role of the environment and other factors that may affect the endosperm texture is also examined together with the role of the puroindoline genes at theHa locus. Finally, we compare endosperm hardness in wheat and in barley.     

全豆营养馒头的成分测定与评价

为评价熟豆豆浆与小麦富强粉混合加工而成的全豆营养馒头的营养情况,本研究分别检测全豆营养馒头和传统小麦粉馒头(标准粉馒头、富强粉馒头)的基本营养成分、氨基酸组成、氨基酸质量、脂肪酸组成及维生素和矿物质含量等,并通过方差分析和LSD检验方法进行对比分析。结果表明：全豆营养馒头的碳水化合物含量显著低于传统小麦粉馒头;全豆营养馒头中脂肪、膳食纤维、灰分、氨基酸总和、8种必需氨基酸总和、氨基酸评分、脂肪酸种类、3种脂肪酸(SFA、MUFA、PUFA)总量、人体必需脂肪酸(亚油酸和α-亚麻酸)、维生素E、钙、钾、锌及钠含量均显著高于传统小麦粉馒头;全豆营养馒头的蛋白质、核黄素、磷、镁、铁、硫胺素和烟酸含量均显著高于富强粉馒头;全豆营养馒头较传统小麦粉馒头还增加了大豆异黄酮成分。因此,全豆营养馒头较传统小麦粉馒头的营养成分更全面,不仅可以作为我国居民更营养健康的主食,还可以改善居民的膳食结构,更符合健康饮食的需求。     

感官评定与仪器分析在北豆腐品质评价中的应用

采用感官评定、质构测定及色泽测定对不同大豆品种加工的北豆腐的品质进行了研究.结果表明:感官评定与仪器测定指标间具有良好的相关性.仪器测定指标中硬度、胶着性、咀嚼性、L*值与感官的总体可接受性呈显著相关关系,相关系数分别为-0.642、-0.447、-0.620、0.624.建立了各相关指标间的回归方程,F值及相关系数R...     

Gas Cell Stabilisation and Gas Retention in Wheat Bread Dough

Gas cell stabilisation and gas retention are of considerable interest because of their technological significance in bread making. We review recent studies in relation to the stabilisation of gas cells and the mechanisms of gas retention, and discuss how these may be affected by the liquid phase of dough. The possibility is discussed of the involvement of surface active materials, such as proteins and pentosans dissolved in the dough aqueous phase, and, perhaps more importantly, non-starch polar lipids in the formation and stabilisation of gas cells. There is accumulating evidence for the hypothesis that liquid films play a critical role in the mechanisms of gas retention in dough. The hypothesis proposes that two closely related, consecutive stages are involved in dough expansion. During the first stage, the expanding gas cells remain discrete until discontinuities develop in the starch–protein matrix, leaving areas containing only a liquid film. The timing and the degree to which such discontinuities occur is largely dependent on gluten proteins. The second stage involves an increase in the surface area of the liquid film as discontinuities become increasingly frequent during expansion. Failure of the lamellar film to maintain the rate at which new surface area is generated leads to the rupture of this film and, consequently, the loss of gas retention. Consideration is also given to the role of bakery fat in gas retention and to additional factors that affect gas retention in wholemeal doughs, in particular the physical disruption of the foam structure of such doughs by components of the outer layers of the grain.     

小麦慢病性的遗传育种研究进展

小麦白粉病和锈病是危害小麦生产的主要病害,培育抗病品种是防治小麦白粉病和锈病最经济有效且环保的方法。慢病性通过成株期延迟病菌的侵染、生长和繁殖而表现出中等抗性．较小种专化抗性持久稳定。小麦慢锈性常由2～4个基因共同作用,慢务锈和慢叶锈分别由Yr和Lr基因复合系统（Yr或Lr基因与几个加性慢病基因互作）控制;慢白粉性表现为明显的数量性状特性,在小麦染色体中,有14对染色体与慢白粉性有关。慢病性的鉴定方法和指标尚无定论。一般认为．病程曲线下面积（AUDPC）较为可靠,而倒二叶严重度可作为简易指标。CIMMYT所采用的旨在聚合微效基因以提高小麦对锈病和白粉病的持久抗性的方法值得借鉴。     

Effects of Emulsifiers on Pita Bread Quality

The purpose of this study was to investigate the effects of emulsifiers [sodium stearoyl-2-lactylate (SSL), glycerol mono stearate (GMS-90), di-acetyl tartaric acid esters of monoglycerides (DATEM), S-570, S-1170, S-1670, P-1670] on pita bread quality. Three flour types (soft wheat flour with 10·0% protein, hard red winter wheat flour with 11·6% protein, and hard red spring wheat flour with 14·4% protein) and three emulsifier concentrations (0·25%, 0·50%, 0·75%, flour basis) were used. Pita breads were baked in an air impingement oven. Loaves were scored on the first and second days, and the influence of the more effective emulsifiers on shelf life stability were investigated after 5 days. Analysis of variance indicated that the flour of moderate protein content (11·6%) resulted in the best overall product quality. The high protein flour (14·4%) gave a dough with high water absorption and bread loaves with dark crust color. On the other hand, the low protein flour (10·0%) had low water absorption. The loaves were uniform in texture and thickness for top and bottom layers, and had a light crust color. All emulsifiers improved the tearing quality of the product. The low concentration (0·25%) of SSL, S-1170, S-1670, and S-570 with flour of moderate protein content (11·6% protein) resulted in a good quality pita bread. No significant differences occurred amongst breads containing those emulsifiers for ability to roll and fold and tearing quality after 5 days of storage at room temperature.     

面包质量与面包小麦品质指标关系的分析

为寻找与面包品质关系最为密切的小麦品质指标并为面包小麦品质改良提供参考,根据农业部谷物品质监督检验测试中心2007年对冀、鲁、豫、皖等12个省(区、市)156份强筋、中强筋小麦样品的品质检测结果,进行了面包烘培质量与小麦品质性状相关多元回归和主成分分析.回归分析表明,面包体积主要受籽粒粗蛋白含量和最大拉伸比例的影响;外观形状、面包评分主要受最大拉伸比例、拉伸比例和粗淀粉含量的影响;纹理结构主要受面筋强度和延伸性的影响.主成分分析表明,R5拉伸阻力和最大拉伸阻力延伸度和支链淀粉可以代表小麦品质指标的大部分信息.研究结果表明,籽粒粗蛋白含量、面筋强度和支链淀粉含量对面包品质有很强的正向贡献,粗淀粉含量对面包品质有负向作用;面团的拉伸特性是小麦品质最重要的指标,是面包小麦品质改良的重要依据.