Depolymerisation and Re-polymerisation of Wheat Glutenin During Dough Processing. I. Relationships between Glutenin Macropolymer Content and Quality Parameters

The protein content and the content of protein-related parameters of both flour and dough were related to the maximum resistance (R_max) and extensibility (E) of dough, as determined in a Brabender Extensograph, and to loaf volume. The glutenin macropolymer (GMP) content of flour and dough was more strongly related toR_maxthan protein content or the content of the group of Osborne fractions (glutenin, gliadin, albumin/globulin). Within each group of protein-related parameters, the contents of the Osborne glutenin fractions explained the variation in all quality parameters better than the contents of the gliadin or albumin/globulin fraction. The GMP content of dough after 45 min rest was more strongly related toR_max, whereas the GMP content of flour was more strongly related toEand loaf volume. This demonstrates that, during mixing and resting of dough, changes occur in the GMP that are important forR_maxbut not forEor loaf volume. Although limited numbers of wheat cultivars (15), harvest years (2), flour blends (8) and resting times (3) were investigated, the relationship between the GMP content of dough andR_maxwas independent of these variables.     

Factors Governing Levels and Composition of the Sodium Dodecyl Sulphate-Unextractable Glutenin Polymers During Straight Dough Breadmaking

The effect of several additives (1·215 μmol KIO₃, 0·892 μmol cysteine, endo-xylanase and 0·5% (w/w) rye-water-extractable arabinoxylans) on changes in the level and glutenin subunit composition of the sodium dodecyl sulphate (SDS)-unextractable protein during breadmaking was investigated. Protein extractability drastically increased during dough mixing and was enhanced both by cysteine and KIO₃. The mixing-induced increase in protein extractability was partly reversed during fermentation. Fermenting doughs containing endo-xylanase had a higher level of SDS-unextractable protein than control doughs, while with KIO₃the amount of SDS-unextractable protein remained very low. During baking most protein became SDS-unextractable. Bread baked from doughs with added KIO₃contained a significantly higher level of SDS-extractable protein. Changes in subunit composition of the SDS-unextractable glutenin polymers, determined with RP-HPLC, coincided with changes in protein extractability during dough processing. Mixing decreased the ratio of high to lowM_rglutenin subunits. Simultaneously, the relative proportions of the different highM_rglutenin subunits in the unextractable glutenin polymers changed. During fermentation changes in subunit composition of the SDS-unextractable glutenin were opposite to those during mixing.     

小麦谷蛋白大聚合体含量的影响因素

小麦籽籽谷蛋白大聚合体（ＧＭＰ）的含量反映了谷蛋白聚合体的粒度分布情况,其高低与其他烘烤品质性状有密切的关系。本文对其影响因素进行了研究。结果表明,ＧＭＰ含量受Ｇｌｕ－１位点等位基因变异、亚基相对含量和环境因素等的影响。其中,Ｇｌｕ－Ａ１ｂ和Ｇｌｕ－Ｄ１ｄ对ＧＭＰ含量有正效应,而Ｇｌｕ－Ａｌｃ和Ｇｌｕ－Ｄ１ａ对ＧＭＰ含量有负效应;Ａ组和Ｃ组亚基的相对含量分别与ＧＭＰ含量正相关和负相关。ＧＭＰ含量也     

Functional Properties of Wheat Gliadins. I. Effects on Mixing Characteristics and Bread Making Quality

The effects of addition of total gliadin and gliadin subfractions on the 2 g Mixograph parameters and loaf volume data of cv. Hereward base flour were studied. The addition of increasing levels of total gliadin and gliadin subgroups to cv. Hereward base flour decreased the overall dough strength, as evidenced by decreases in the values for mixing time (MT), mixing stability (MS) and work input (WI). The decreasing order of these parameters for different gliadins was: ω1- >, γ-, > β-, > α-gliadins. The mixing tolerance, as measured by resistance breakdown (RBD) and bandwidth breakdown (BWBD), decreased as a result of addition of different fractions. However, Peak dough resistance (PDR) values increased with addition of individual groups of gliadins and gluten to the base flour. A linear relationship was found between the PDR and loaf volume when individual groups of gliadin were added to the base flour. The ω-gliadins produced the least positive effects on PDR. Addition of total gliadin and its subgroups substantially improved loaf volumes of pan breads. The ω-gliadins again resulted in a smaller increase in loaf volume.     

种植密度对小麦籽粒HMW GS含量及GMP粒度分布的影响

为给小麦优质栽培提供理论依据,以强筋小麦品种藁优8901和中筋小麦品种泰农18为材料,研究了高（HD,24×10⁵·hm^-2）、中（MD,18×10⁵·hm^-2）、低（LD,12×10⁵·hm^-2）3个种植密度对小麦籽粒高分子量谷蛋白亚基（HMW GS）含量和谷蛋白大聚合体（GMP）形成的影响。结果表明,在不同种植密度下,藁优8901的GMP含量表现为MD＞HD＞LD,而泰农18则表现为MD＞LD＞HD,均以MD的最高。不同密度条件下藁优8901籽粒的总HMW GS含量均高于泰农18,表明强筋小麦具有较强的谷蛋白积累能力。2个品种籽粒的单个HMW GS含量对不同种植密度的响应不同,但都以MD的最高,种植密度过高、过低均不利于小麦籽粒HMW GS含量的提高。GMP的粒度分析表明,MD处理提高了2个品种籽粒GMP大颗粒（粒径＞100 μm）体积百分比,说明中等种植密度有利于大粒径GMP颗粒的形成。     

圆锥小麦地方品种面筋和面团流变学特性研究

为了拓宽小麦品质育种遗传资源,对27份圆锥小麦地方品种的面筋和面团流变学特性进行了分析.结果表明,供试品种间存在较大差异,其面筋指数平均为63.02%,变幅为23.58%～99.78%;湿面筋含量平均为41.19%,变幅为30.21%～49.66%;干面筋含量平均为13.07%,变幅为10.09%～15.77%;蛋白质含量平均为13.80%,变幅为10.11%～16.06%.其粉质仪参数表现为吸水率较高,形成时间、稳定时间和断裂时间较短,公差指数表现一般与形成时间和稳定时间均值分别为3.1min(变幅为1.2～7.5min)和3.9min(变幅为0.6～11.4min).蛋白质与湿面筋和干面筋含量之间表现为极显著正相关,与形成时间呈显著正相关.面筋各参数相互之间,以及粉质仪各参数相互之间存在不同显著程度的相关,但两类参数之间相关不显著.分析表明圆锥小麦地方品种中可能具有普通小麦品质改良所需的优异基因资源,对于品质育种具有重要利用价值.     

Effects of α-, β-, γ- and ω-Gliadins on the Dough Mixing Properties of Wheat Flour

Gliadins were extracted from wheat and individual groups (α-, β-, γ-, ω-1 and ω-2) purified. The effects of the individual groups of gliadin on the mixing properties of doughs from low and high protein flours were measured on a 2-g Mixograph and a prototype microextension tester. The addition of all groups of gliadin resulted in a decrease in dough strength. The relative weakening effects were ω-1>ω-2≈α-≈β->γ- in the Mixograph, and γ->α-≈β-≈ω-2≈ω-1 in the Extensograph.     

收获期对小麦粉面团流变学特性的影响

为分析不同收获期的小麦品质,以济麦17、济麦20和济麦22三个品种为试验材料,收获时间分别为5月31日、6月5日、6月9日、6月12日和6月15日,采用主成分分析和因子分析的方法评价面团流变学特性。结果表明,收获期对小麦品质有一定的影响,济麦17、济麦20、济麦22的品质最佳收获期分别为6月12日、6月15日、5月31日。随着收获期的延长济麦17的品质呈＂差-好-差＂的变化趋势,济麦22与之相反,济麦20的品质随着收获期的延长而提高。通过提早收获,中筋小麦品种济麦22可以达到强筋品种济麦17的最佳品质。     

Effects of Alkali and Acid on Dough Rheological Properties and Characteristics of Extruded Noodles

The effects of alkaline salt (kansui) and lactic acid on the rheological properties of wheat flour dough were evaluated using a capillary rheometer and an oscillatory rheometer. The contents of sulphhydryl groups and disulphide bonds in doughs were also determined. Kansui significantly increased the apparent viscosity and storage modulus (G′) and decreased the loss tangent, and resulted in the reduction in protein extractability. It appeared that the addition of kansui increased the proportion of solid-like behaviour in dough. Lactic acid had the opposite effect and resulted in a dough with less shear thinning. The gelatinisation of starch caused a remarkable increase in G′ and reduce the difference in G′ and tan δ among the samples. The correlation between dough rheology and characteristics of extruded noodles was also discussed.     

稻米中蛋白质对淀粉RVA特征谱的影响

通过分析蛋白酶或还原剂二巯基苏糖醇（DTT）分别去除稻米蛋白质或打破蛋白质二硫键后,稻米RVA（Rapid Visco Analyzer）特征谱形成和特征值的变化,研究蛋白质对淀粉RVA特征谱的影响,以及对米饭食味品质的作用。在淀粉糊化过程中,蛋白质使RVA特征谱的峰值黏度、冷胶黏度等值升高,改变RVA线性上升段的斜率。蛋白质可能通过二硫键结合形成的蛋白质网络本身和通过吸水减少淀粉水合的有效水量,协同提高糊化多相体系的浓度,增强分散相与黏稠相的互作。蛋白质影响米饭食味品质,可能通过改变米粒的吸水性而起作用。     

Functional Properties of Wheat Gliadins. II. Effects on Dynamic Rheological Properties of Wheat Gluten

The effects of addition of purified total gliadin and its subgroups (α-, β-, γ- and ω-gliadins) on the dynamic rheology of gluten were investigated. The frequency sweeps of gluten with added α-, β-, γ- and ω2-gliadins showed unexpected increases in the magnitude of G′ and G′′, suggesting stiffening of the native gluten. Conversely, a reduction in the magnitude of G′ and G′′ occurred upon addition of the total gliadin fraction and the ω1-gliadin, implying softening of the gluten. Addition of individual gliadin fractions increased the values of slope log G′ vs log frequency, suggesting increased concentrations of uncrossed-linked material compared with the native gluten. There were significant differences in the slope values for individual gliadin fractions. The increasing order of slopes for different gliadins was: β- >γ- >α- =ω1>ω2, indicating that glutens containing ω- and α- gliadins are relatively less crossed-linked than those containing β- and γ-gliadins. The dynamic moduli, G′ and G′′, of cv. Hereward gluten showed significant positive relationships with Mixograph parameter peak dough resistance (PDR), and loaf volume for gliadin subgroups added to cv. Hereward flour.     

辣木籽渣组分蛋白的理化与功能性质研究

辣木籽渣是辣木籽提取油之后的副产物,为了提高其综合利用价值,本文以辣木籽渣为原料,通过奥斯本(Osborne)四步法提取清蛋白、球蛋白、谷蛋白和醇溶蛋白,分析比较了4种组分蛋白的理化性质及功能特性.结果表明:清蛋白、球蛋白、谷蛋白和醇溶蛋白的提取率分别为10.34％、0.69％、3.40％和3.65％,纯度均在82％以...     

大豆乳清蛋白的热促凝聚及其对分离蛋白功能性的影响

分别在pH8.0和pH4.5对"碱提酸沉"法制备大豆分离蛋白过程中所得提取液进行热处理,研究了大豆乳清蛋白的热促凝聚效果及其对所制备分离蛋白功能性的影响。结果表明:加热处理可降低大豆乳清中乳清蛋白的含量,在pH8.0和pH4.5时提取液经70℃加热10 min分别使25.7%和40%乳清蛋白转移到分离蛋白产品中。以普通分离蛋白为对照,对3种分离蛋白产品进行功能性分析,发现3种产品均在pH4.5~4.8的范围内溶解度最小,70℃加热10 min所制备分离蛋白的持水性明显高于普通分离蛋白,但其持油性、起泡性、泡沫稳定性和乳化性均低于普通分离蛋白,而乳化稳定性无显著差异。     

大豆蛋白的结构、营养及功能性质的研究进展

简要综述了大豆分离蛋白、大豆伴球蛋白及大豆球蛋白的结构、营养价值及功能等方面的研究进展,对大豆蛋白在食品体系中的广泛应用提供参考。     

冷激对玉米幼苗可溶性蛋白质含量与组分的影响

以胚芽期与3叶期玉米幼苗叶片为试材,进行0、2、4、6℃温度下冷激处理,分析不同冷激强度与可溶性蛋白质含量及组分的关系。结果表明,冷激处理下可溶性蛋白质含量先增加后减少;胚芽期增加幅度大于3叶期,3叶期幼苗在较低温度下(0℃、2℃)可溶性蛋白质含量先降低后升高。冷激蛋白的诱导在不同苗龄表现不一致,胚芽期有部分蛋白质带(40KD、26KD)表达增强,但没有发现新的蛋白质。3叶期幼苗有分子量在80KD、45KD左右的两条新蛋白带。温度越低出现的新蛋白越少,随着温度的升高新蛋白出现的时间越迟。     

硫对不同蛋白质含量春小麦面团流变学特性的调节效应

为给小麦优质栽培提供理论依据,以3个不同蛋白质含量的春小麦品种为材料,在不同施氮水平条件下研究了施硫对面团流变学特性的调节效应.结果表明,施尿素60 kg/ha(低氮)和128 kg/ha(高氮)条件下,各品种面团韧性随着施硫量的增加总体上呈降低趋势.高氮条件下,施硫对高蛋白品种面团延展性提高不利,且降低吸水率,但可以增加面团形成时间;施纯硫0～50 kg/ha有利于改善低蛋白品种NKH9面团的延展性,对面团形成时间的调节作用呈负效应;施硫对各品种稳定时间的作用趋势与面团形成时间的作用趋势相同.低氮条件下施硫可增加所有供试品种面团形成时间,改善面团延展性.相关分析结果表明,低氮条件下,施硫对小麦品种野猫和东农7742的W值有提高的作用,但不明显;高氮条件下施硫对W值的作用却呈明显的负效应,但两种氮处理条件下施硫对新克旱9的W值作用呈不显著的负效应;施尿素60 kg/ha条件下施硫可提高高蛋白品种的烘焙指数.高氮条件下,施硫可以明显提高高蛋白品种面团形成时间和稳定时间,但对低蛋白品种的作用却相反.     

大豆膳食纤维对面团流变学特性及面制品品质影响的研究进展

随着人们对均衡膳食和高品质面制品需求的不断提高,通过添加大豆膳食纤维改良面团流变学特性,进而在一定程度上改良面制品品质成为新的研究热点.该文综述了近年来添加大豆膳食纤维改善面团流变学特性及面制品品质方面的研究进展.同时,归纳了大豆膳食纤维改善面团流变学特性及面制品品质的作用机理,为加工富含大豆膳食纤维的高品质面团及面制...     

Effects of Aluminum Deposition on the Functional Properties of the Meta-aramid Fabrics

Meta-aramid fabrics were deposited with aluminum to examine the effects of aluminum deposition on the functional properties of meta-aramid fabrics. Various functional properties of the aluminum deposited meta-aramid fabrics were assessed with sputtering processing parameters such as chamber pressure and sputtering power. SEM-EDX was utilized to investigate surface morphology and compositions of the deposited meta-aramid fabrics. The optical, thermal, electric, and abrasive properties of the deposited meta-aramid fabrics were measured by color reader, KES-F7 thermo-Lab 2 system, milliohm meter, and abrasion testing machine. The obtained results indicated the optical, thermal, electric, and abrasive properties of the deposited meta-aramid fabrics were influenced clearly by deposition processing parameters. The light reflectance, thermal conductivity, electric resistance, and abrasion strength of the aluminum deposited meta-aramid fabrics were shown to be a maximum at a chamber pressure and a sputtering pressure, and the optimum deposit condition could be established.     

青海高原春小麦HMW—GS等位基因变异及其对面团流变学特性的作用

为了给青海高原春小麦改良提供资料。分析了青海育成和国内外引进的125个春小麦品种(系)的HMW—GS等位基因变异。并测定了其中58个品种(系)在青海高原环境下的面团流变学特性。结果表明：(1)参试春小麦品种(系)的HMW—GS存在广泛的变异。Glu—A1位点出现3个等住基因，Glu—B1住点出现5个等住基因，Glu—D1位点出现4个等位基因；共出现了22种HMW—GS组合形式。其中1.7 8.2 12和N，7 8，2 12组合类型出现频率最高。并发现了个别罕见的变异类型，如2 10，10。(2)亚基组合类型对沉淀值、形成时间、稳定时间、评价值等品质性状影响较大，对籽粒蛋白质含量、出粉率和面粉吸水率的影响不显著。试验还表明，HMW—GS组成与面粉的筋力有密切关系。     

Effect of Barley and Barley Components on Rheological Properties of Wheat Dough

The effects of addition of whole barley and barley components (starch, β-glucans and arabinoxylans) on rheological properties of dough prepared from wheat flours with variable gluten quality (cv. Glenlea, extra-strong; cv. Katepwa, very strong; cv. AC Karma, strong; and cv. AC Reed, weak) were investigated in these studies using Mixograph and dynamic rheological measurements. Whole barley meal, starch and non-starch polysaccharides from hulless barley with variable starch characteristics (normal, high amylose, waxy, and zero amylose waxy) were tested. Upon addition of either β-glucans or arabinoxylans, significant increases in peak dough resistance, mixing stability, and work input were recorded in all flours. The addition of starch to various wheat flours reduced the strength of the respective flour-water doughs. The improvement of dough strength upon addition of waxy or zero amylose waxy barley meal was associated with the high content of total and soluble β-glucans present in barley samples. The addition of arabinoxylans or β-glucans increased the G′ of wheat doughs; arabinoxylans had a greater effect than β-glucans. Starch substantially decreased the elastic modulus of dough prepared from cv. Glenlea but waxy and high amylose starches increased the G′ of dough prepared from cv. AC Karma. A combination of the high amounts of non-starch polysaccharides and unusual starch characteristics in barley seems to balance the negative effects associated with gluten dilution brought about by addition of barley into wheat flour.