Water-extractable Arabinoxylan from Pearled Flours of Wheat,Barley, Rye and Triticale. Evidence for the Presence of Ferulic Acid Dimers and their Involvement in Gel Formation

Cereal grains from wheat, barley, triticale and rye were pearled and milled. Part of the flours were treated in boiling aqueous ethanol and both the ethanol-treated and untreated flours were extracted with water. Yields of arabinoxylan in the extracts were higher for the untreated flours. Chemical, physico-chemical and structural studies showed differences between the arabinoxylans in extracts of the different cereals although arabinoxylans extracted from untreated and the corresponding ethanol treated flours were similar in neutral sugar content and patterns of substitution. Analyses showed that low amounts of ferulic acid dimers (8-O-4′, 8-5′, and 5-5′ forms) were present in all the extracted arabinoxylans. Oxidative gelation studies, using peroxidase/H₂O₂, revealed significant differences in the capacity of extracted arabinoxylans to form gels via intermolecular cross-linking. The values of elastic modulus (G′) of gels from the arabinoxylan extract of ethanol-treated flours varied from 2 to 40 Pa and were higher than those obtained from the untreated flours (0·2–6 Pa).     

Phytic Acid Level in Wheat Flours

The phytic acid content of refined (hand-made and factory-made) and whole (factory-made) wheat flours, much consumed in the Canary Islands, have been determined in this study. A total of 200 samples of flours from different types (100 refined and 100 whole) were analysed. The method proposed by Garcı́a-Villanova et al. (1982) was used for determination of phytic acid content in wheat flours. Most of the phytic acid concentrations are within the range 2–4 mg/g for the refined flours and 6–10 mg/g for the whole ones. The arithmetic mean obtained from all the samples studied is 3·77 mg/g for hand-made, refined flours, 2·96 mg/g for factory-made refined flours and 8·50 mg/g for the whole ones. On analysing the phytic acid content in all the flour samples, significant differences were observed for the different types of flour. Refined flours had a content lower than whole ones.     

Evidence for the Presence of Only One Cysteine Residue in the D-type Low Molecular Weight Subunits of Wheat Glutenin

D-type low molecular weight subunits of bread wheat glutenin have ω-gliadin type N-terminal amino acid sequences, but are incorporated into the glutenin polymers because of the presence of cysteine residues. In order to determine the number and position of cysteine residues, ID-encoded D-type low molecular weight subunits of wheat glutenin were purified from the cv. Chinese Spring using a procedure that allowed high recovery. Comparison of the molecular weights of alkylated and unalkylated subunits by MALDI mass spectrometry indicated the presence of only one cysteine residue per molecule. This was supported also by the detection of dimers of D subunits in gluten. An internal sequence of 62 amino acids preceding the cysteine was obtained, but it was not possible to identify the cysteine residue, either because it was not within the range of N-terminal sequencing of peptides obtained, or because it was present in one of the two unidentified positions.     

关中平原小麦粉鲜面条制作适宜性研究

针对餐饮业连锁经营和向食品制造转化的背景下,食品生产企业对小麦品种质量特性、原料质量稳定性,特别是面条制作适宜性提出新的要求,对关中平原大面积种植的小麦品种籽粒质量性状进行分析,并通过训练的专业感官评价人员对以其为原料、由面点师实验室制作的鲜面条的烹饪特性进行评价,同时统计分析小麦籽粒性状、面粉理化特性和面条感官评价结果之间的关系。结果表明,关中平原小麦千粒重、容重和硬度较高,面粉湿面筋含量高,面团延展性能良好,优质强筋小麦品种的比例明显提高。面粉的黏度参数,特别是峰值黏度,对面条的感官评价总分,面条质量要素中的色泽、硬度和黏性有较大影响,是评价鲜面条专用粉的重要参考指标。面条感官评价总分与峰值黏度呈显著正相关,与籽粒硬度、破损淀粉含量和面粉吸水率呈显著或极显著负相关。小麦品种（面粉）百农207、F50、F20、中麦578、西农583和郑麦366适宜制作优质鲜面条。     

河北省小麦面粉及加工制品色泽研究

为了给小麦品质育种及加工提供参考,系统研究了河北省推广小麦品种面粉及加工制品的色泽状况,并进行了相关性分析。结果表明,河北省小麦面粉样品白度值平均为76.19％,变幅为73.67％～81.17％; L_*值平均为95.76, 变幅为94.53~96.67,a_*值平均为0.56, 变幅为0.25~0.79,b_*值平均为8.79, 变幅为6.64~10.67;加工成生面片后样品L_*值下降,a_*、b_*值上升,制成熟面片后样品L_*、a_*值整体下降,b_*值略有上升;河北省小麦面粉样品色泽在红-绿方向都略偏向红色,在黄-蓝方向都偏向黄色;同时各小麦品种的面粉及加工成生、熟面片的L_*、a_*、b_*值之间存在差异,其中面粉的b_*值与其色泽相关性最大。     

Correlations of the Amount of Gluten Protein Types to the Technological Properties of Wheat Flours Determined on a Micro-scale

Flour samples of 14 wheat cultivars previously characterised by rheological measurements and by baking tests on a micro-scale (Kieffer et al.: Journal of Cereal Science27 (1998) 53–60) were analysed for the relative amounts of gluten protein types using a combined extraction/HPLC procedure. Regression analysis was used to find relations between wheat properties and protein quantities. The results indicated that the maximum resistance of dough and gluten and the gluten index were strongly dependent on the quantity of glutenin subunits (GS) in flour; additionally they were influenced by the ratio of gliadin to glutenin subunits. Within the family of glutenin proteins, the correlation coefficients for high-molecular-weight (HMW) and low-molecular-weight (LMW) GS were in a similar range, but twice the amount of LMW GS was necessary to get the same resistance as with HMW GS. Among HMW GS, the contribution of x-type GS was more important than those of y-type GS. The extensibility of dough and gluten was mainly dependent on the ratio of gliadin to total glutenin subunits, to HMW GS and LMW GS. Dough development time showed the highest correlation with total HMW GS and x-type HMW GS. Bread volume was influenced by the total amount of gluten protein more than by the amount of protein in different groups or of different types, probably because of the rather low range of flour protein content (8·7–12·0 %) within the set studied. Significant differences between gliadins and glutenins with respect to their effects on bread volume could not be detected. The correlation between bread volumes and the quantity of gluten proteins was higher, when dough was mixed to optimum.     

HP-SPME-GC-MS结合ROAV分析新疆不同小麦品种面粉主要挥发性成分

为了解新疆小麦面粉挥发性成分组成,用顶空固相微萃取气相色谱-质谱联用技术(headspace solid phase microextraction gas chromatography-mass spectrometry,HS-SPME-GC-MS)测定12个小麦品种的挥发性物质构成,结合相对气味活度值(relative odor activity value,ROAV)、主成分分析(principal component analysis,PCA)和聚类分析,分析新疆不同小麦品种面粉中的关键香气成分构成差异。结果表明,12个小麦面粉样品中共鉴定出143种挥发性化合物,其中烷烃类50种,烯烃类8种,醛类13种,醇类28种,酮类16种,酯类7种,酸类4种,苯类9种,其他化合物8种。ROAV分析发现不同小麦品种面粉主要挥发性物质有12种：己醛、壬醛、反-2-辛烯醛、癸醛、(E,E)-2,4-壬二烯醛、1-辛烯-3-醇、2-正戊基呋喃、正己醇、1-壬醇、6-甲基-5-庚烯-2-酮、3-辛烯-2-酮、γ-壬内脂。主成分和聚类分析表明,春小麦、冬小麦分别聚为一类。     

新疆市售小麦面粉制作新疆拉面的加工品质特性及其专用粉品质评价指标的研究

为给新疆拉面专用品种选育提供理论依据,2006年对29份来自新疆北部和东部10个主要城市市场销售的面粉样品进行了品质测定和新疆拉面加工品质特性的研究.结果表明,降落数值、灰分含量、面团流变学特性、淀粉粘度特性以及面粉色泽等22个主要品质性状对新疆拉面感官评价总分有显著效应,但作用大小和方向各有不同,其中拉伸阻力与延展度的比例、面团强度、延展性等性状的作用较大.相关分析显示,拉面手感与延伸性呈显著正相关,与配置比、反弹值呈显著负相关,拉面色泽与灰分含量、稳定时间、拉伸阻力、拉伸比例和筋力呈显著负相关,拉面质地(韧性、适口性、光滑性)主要与面团流变学特性参数密切相关,新疆拉面感观评价总分与延伸性呈显著正相关,与配置比和反弹值呈显著负相关.有10个样品能够制做出优质新疆拉面,占34.5%,对其品质性状研究后认为新疆拉面专用面粉的品质指标为:降落数值≥250 s,灰分含量≤0.55%,蛋白质含量11.6%～12.8%,湿面筋含量28.9%～32.3%,Zeleny沉淀值≥30 mL,稳定时间4.1～7.9 min,延展性140～168 mm,拉伸阻力166～250 BU,最大拉伸阻力200～400 BU,拉伸面积50～82cm2,淀粉峰值粘度248～289 RUV,反弹值98～116 RUV,亮度(L*)89～91,黄度(b*)≤6.吹泡仪品质参数中的面团延伸性(L)和面团配置比(P/L)与新疆拉面感官评价总分关系密切,也可以用于新疆拉面专用面粉的品质评价,其品质指标为面团弹性(P)66.0～133.0 mm,面团延伸性(L)58.0～121.0 mm,面团配置比(P/L)0.6～2.3,面团膨胀指数(G)16.9～24.5 mL,面团筋力(W)155.0～290.0 MJ,面团弹性指数(I.e.)40.7～53.1.     

Wheat Bread Quality as Influenced by the Substitution of Waxy and Regular Barley Flours in Their Native and Extruded Forms

The substitution of wheat flour with barley flour (i.e. native or pretreated/extruded) reduced the loaf volume. Depending on the barley variety and flour pretreatments, the colour and firmness/texture of the bread loaves were altered. Amongst the barley breads prepared from native flours (at 15% barley flour substitution level), Phoenix had higher loaf volume and lower crumb firmness than Candle. However, amongst the barley breads prepared from extruded flours, CDC-Candle had higher loaf volume and lower crumb firmness than Phoenix. The lower loaf volume and firmer crumb texture of barley breads as compared with wheat bread may be attributed to gluten dilution. Also, the physicochemical properties of barley flour components, especially that of β-glucan, can affect bread volume and texture. β-glucan in barley flour, when added to wheat flour during bread making, could tightly bind to appreciable amounts of water in the dough, suppressing the availability of water for the development of the gluten network. An underdeveloped gluten network can lead to reduced loaf volume and increased bread firmness. Furthermore, in yeast leavened bread systems, in addition to CO₂, steam is an important leavening agent. Due to its high affinity for water, β-glucan could suppress the amount of steam generated, resulting in reduced loaf volume and greater firmness. In the present study, breads made with 15% HTHM CDC-Candle flour had highly acceptable properties (loaf volume, firmness and colour) and it indicated that the use of extruded barley flours would be an effective way to increase the dietary fibre content of barley breads.     

Wheat Bread Quality as Influenced by the Substitution of Waxy and Regular Barley Flours in Their Native and Cooked Forms

The substitution of wheat flour with barley flours altered the bread loaf volume, colour and bread crumb firmness. These changes were found to be dependent on the barley cultivar, substitution level and flour treatment. In native form, Phoenix barley flour at 15% substitution produced breads with bigger loaf volume and softer crumb than Candle barley flour. However, when the barley flours were heat-treated (pan-cooked in excess water and then dried) before substitution, Candle barley flour produced better quality breads in terms of loaf volume, crumb firmness and crust colour than the Phoenix counterparts. The baking functionality of Candle flour was markedly improved when added after heat treatment.     

Evidence for the Non-Glycoprotein Nature of High Molecular Weight Glutenin Subunits of Wheat

An isolation and purification procedure for wheat high molecular weight glutenin subunits (HMW-GS) involving no steps expected to cause deglycosylation of glycoproteins was developed to allow removal of the maximum amount of carbohydrates not covalently linked to HMW-GS. Flour was defatted and then extracted with 50%n-propanol (50%n-PrOH) to remove arabinogalactans and glucose-containing material. HMW-GS were extracted with 50%n-PrOH containing 5% β-mercaptoethanol, precipitated in 60%n-PrOH, alkylated and recovered by precipitation. The partially purified HMW-GS were separated by cation exchange chromatography and resulting fractions purified by RP–HPLC. The purified HMW-GS contained only 0·1% of glucose (corresponding to 51–59 monosaccharide residues per 100 HMW-GS molecules) and no other amino or neutral sugars. The HMW-GS gave a positive reaction in a periodate–digoxigenin glycan detection assay when labelled in solution (with or without periodate oxidation) but not when labelled directly on-the-blot. HMW-GS expressed inEscherichia coli, a micro-organism without glycosylation capabilities, reacted in an identical way. Possible reasons are given for the difference in results obtained after labelling in solution or on-the-blot. No positive reaction between the purified HMW-GS and mannose-specificGalanthus nivalisagglutinin was observed. The presence of N-acetylglucosamine in HMW-GS has been previously reported²⁰. Since neither mannose nor N-acetylgalactosamine were found in the HMW-GS, and these proteins lack the sequon necessary for N-glycosylation, only O-linked GlcNAc moieties are possible. This modification could not be detected using a galactosyltransferase labelling assay. Taken together these results suggest that HMW-GS are not glycosylated.     

木聚糖酶抑制剂基因与小麦白粉病病情指数的关系

为了解木聚糖酶抑制剂基因(TAXI型、XIP型和TLXI型)与小麦白粉病病情指数的关系,选取来源于不同麦区的192份小麦品种,以特异PCR方法检测木聚糖酶抑制剂基因,田间自然诱发鉴定白粉病病情指数。结果表明,含有TAXI-I基因的77份品种的平均病情指数(8.99)比不含有TAXI-I基因的115份品种的病情指数(11.89)低24%,差异显著;含有XIP-I基因的115份品种和不含XIP-I基因的77份品种的平均病情指数分别为10.86和10.53,差异不明显;含有TLXI基因的116份品种和不含TLXI基因的76份品种的平均病情指数分别为10.33和11.33,差异不显著。说明TAXI-I基因可能是一个有效的白粉病抗性基因。     

Extensional Flow Studies of Wheat Flour Dough. I. Experimental Method for Measurements in Contraction Flow Geometry and Application to Flours Varying in Breadmaking Performance

An experimental method is reported for extensional measurements on wheat flour doughs in contraction flow geometry. In this method the transient stress under constant extension rate was measured, followed by stress relaxation measurement after cessation of flow. Four different wheat cultivars (with large differences in bread volume) were used to evaluate the usefulness of the method and to find how different parameters relevant to baking quality could be extracted from the data. The plot of transient viscosity against time showed the effect known as strain hardening, appearing at a Hencky strain roughly independent of the strain rate but differing between the wheat varieties. The relaxation rate curves for the four wheat varieties were similar except at the highest strain rate, 7·40 s⁻¹. It was decided in the following case study to use the highest strain rate, 7·40 s⁻¹and to extract three parameters from the stress growth plot and three parameters from the stress relaxation rate plot. In the case study, flours of 17 wheat varieties were mixed in the Mixograph to maximum resistance before being subjected to the contraction flow measurement. The six parameters extracted from each wheat flour dough measurement, together with the corresponding protein content, Zeleny value, and bread volume, were evaluated by multivariate analysis. A model for predicting the bread volume from the contraction flow parameters explained 94·6% of the variation in bread volume, while a model with Zeleny values and protein contents included explained 97·2%.     

小麦不同生育时期木聚糖酶活性及木聚糖酶抑制蛋白活性的变化

为给小麦抑制蛋白的分离纯化以及表达研究提供信息,以小麦品种兰考矮早八和豫麦49为材料,检测和分析了小麦在不同生育时期叶片和籽粒木聚糖酶活性及木聚糖酶抑制蛋白活性的动态变化.结果表明,木聚糖酶活性及木聚糖酶抑制蛋白活性在两个品种间没有差异,不同生育时期小麦叶片及籽粒木聚糖酶活性没有显著变化,可能以基础水平存在.叶片中的木聚糖酶抑制蛋白活性自苗期开始,经拔节期到抽穗期,总体呈现增加趋势,但进入灌浆～成熟期则显著下降,而籽粒中的木聚糖酶抑制蛋白活性则随籽粒的成熟持续升高.     

Extensional Flow Studies of Wheat Flour Dough. II. Experimental Method for Measurements in Constant Extension Rate Squeezing Flow and Application to Flours Varying in Breadmaking Performance

An experimental method for biaxial extensional measurements on wheat flour doughs in a squeezing flow geometry is reported, in which the speed is controlled so as to be proportional to the gap between the disks, resulting in a constant extensional strain rate in the sample. In such measurements, the stress was obtained directly as a function of Hencky strain at constant pre-set strain rate. This allowed a straightforward evaluation of the strain hardening phenomenon, its onset and strength. Measurements were made at three strain rates and at Hencky strains varying from 0 to 3 for 15 winter wheat cultivars, five of high (H), five of intermediate (M) and five of low (L) protein content and baking performance. It was concluded that all three groups showed strain hardening, which started before a Hencky strain value of 1 was reached. All three groups, at all three strain rates satisfied the stability criterion n>_Hat all values of Hencky strain (n is the strain hardening index in the power-law representation σ=K_Hⁿwhere σ is the stress, _His the Hencky strain, and K is a constant). Differences between the groups were seen most clearly at the lowest strain rate: (i) the onset occurred at a lower Hencky strain, the higher the protein content and baking quality; (ii) the strain hardening index reached a maximum just before a Hencky strain of 2, where the H group had a 25% higher value than the M and L groups.     

A Wheat Xylanase Inhibitor Protein (XIP-I) Accumulates in the Grain and has Homologues in Other Cereals

We have measured xylanase inhibitor activity against an Aspergillus niger xylanase in different parts of the wheat plant at different stages of development and used immunodetection to determine the spatial and temporal distribution of xylanase inhibitor protein I (XIP-I) in Triticum aestivum var. Soisson. Although xylanase inhibitor activity was detected in all parts of the wheat plant throughout development, XIP-I was located predominantly in the grain tissue, where it appears at a late stage in grain development and persists after germination, indicating that the different xylanase inhibitor proteins are under different regulatory controls. (1,4)-β-Xylanase activity was detected in wheat grains during development and post-germination. Pure XIP-I and a crude sample containing TAXI inhibitors but not XIP-I did not have the ability to inhibit this endogenous (1,4)-β-xylanase activity. Protein extracts from the seeds of various monocots were also tested for the presence of XIP-I, where it was found to be present in the grains of several wheat varieties, rye and barley, but was not detected in rice, sorghum or maize.     

小麦Bowman-Birk型蛋白酶抑制因子的克隆表达及其抑制鱼糜凝胶软化的效果研究

为探究重组小麦(Triticum turgidum)Bowman-Birk蛋白酶抑制剂(BBI)抑制活性特征及其对鲢鱼肌原纤维蛋白自溶反应的抑制效果,采用TA克隆技术克隆小麦BBI成熟肽基因片段,并对原核表达的小麦BBI蛋白进行镍亲和层析纯化,利用SDS-PAGE、TSK-GEL G2000SWxl高效液相色谱检测诱导及纯化效果。在测定重组小麦BBI对胰蛋白酶的抑制活性的基础上,进一步通过SDS-PAGE分析了重组BBI对鲢鱼肌原纤维蛋白自溶反应的抑制作用。结果表明,经双酶切鉴定证实成功获得了BBI成熟肽基因片段,该基因与野生二粒小麦BBI相关基因(GenBank登录号EU346892.1)序列相似性为99.63%。目的蛋白在SDSPAGE及TSK-GEL G2000SWxl高效液相色谱分析中,分别表现为单一带和单一峰,产物得到有效纯化,分子量约10.5kD。该重组小麦BBI对胰蛋白酶有明显的抑制活性。添加量5μg·mg-1重组BBI可显著抑制鲢鱼肌原纤维蛋白(尤其是肌球蛋白重链)在pH 7.5,50℃下的自溶。     

外源ABA及其合成抑制剂对冬小麦叶片抗寒指标的影响

为了研究外源ABA及其抑制剂对低温下冬小麦生理生化指标的影响,以冬小麦东农冬麦1号为试验材料,于三叶期分别叶面喷施10 μmol·L^-1 ABA、5 mmol·L^-1 钨酸钠和50 μmol·L^-1 氟啶酮,田间自然降温条件下,分别于10 d平均最低温度达到4、0、-10、-25 ℃时取叶片测定相关生理生化指标。结果显示,随着温度的降低,各处理组小麦叶片的可溶性糖、可溶性蛋白含量先升后降,在0 ℃达到峰值;脯氨酸、丙二醛（MDA）含量和超氧化物歧化酶（SOD）活性逐渐升高。经ABA处理后,小麦叶片的可溶性糖、可溶性蛋白、脯氨酸含量及SOD活性显著高于对照组,但不同温度下的变化水平有所差异;MDA含量低于对照组,在0 ℃时差异显著,说明外源ABA可提高冬小麦抗寒能力。两种合成抑制剂处理后,小麦叶片的可溶性糖、可溶性蛋白、脯氨酸含量和SOD活性（除0 ℃）均显著低于对照组,MDA含量（除4 ℃）显著高于对照组,说明其对小麦的效应与ABA处理相反,可降低冬小麦抗寒性。钨酸钠处理组各项指标与ABA处理相比变化差异显著,氟啶酮处理组各项指标与ABA处理相比差异极显著,说明ABA在参与冬小麦抗寒性的调控过程中起着重要作用,且氟啶酮对冬小麦抗寒能力影响更大。     

野生二粒小麦和普通小麦及其渐渗系全麦与脱麸面粉蛋白分析

为了解野生二粒小麦籽粒蛋白特性对普通小麦全麦面粉和脱麸面粉的改良价值,以高产弱筋小麦品种川农16(CN16)为母本,分别与籽粒蛋白含量存在显著差异的四倍体野生二粒小麦D1和D97进行远缘杂交,按高产性状定向选择并连续自交获得稳定高世代渐渗系共61份,本研究对61份渐渗系、7份野生二粒小麦和6份普通小麦进行了全麦和脱麸面粉粗蛋白质含量及其各蛋白组分含量分析、比较。结果显示,野生二粒小麦的籽粒粗蛋白(GPC)及其清蛋白、球蛋白、醇溶蛋白、谷蛋白含量均较普通小麦具有更丰富的遗传多样性,各蛋白组分含量均显著高于普通小麦。61份渐渗系中,分别有54.10%和52.46%的材料全麦面粉和脱麸面粉的粗蛋白含量显著高于母本CN16,全麦和脱麸面粉蛋白质含量最高达17.77%和17.62%,较CN16分别提高了5.05和5.33个百分点;全麦和脱麸面粉的清蛋白、球蛋白、醇溶蛋白、谷蛋白分别有18.03%和32.79%、50.82%和62.30%、67.21%和77.05%、37.70%和81.97%的株系高于母本CN16。全麦和脱麸面粉的粗蛋白含量与醇溶蛋白和谷蛋白含量间、贮藏蛋白的各组分间、可溶性与不...