1BL/1RS易位系小麦谷蛋白和醇溶蛋白亚基组成、含量与主要品质性状关系的研究

从106个小麦品种(系)中,鉴定出了17个1BL/1RS易位系小麦品种,用酸性聚丙烯酰胺凝胶电泳(A-PAGE)和SDS-聚丙烯酰胺凝胶电泳(SDS-PAGE)分析了这些易位系小麦品种的醇溶蛋白(Glia)、高分子质量谷蛋白(HMW)、低分子质量谷蛋白(LMW)的组成特点,并对其蛋白质含量、湿面筋含量、沉淀值、稳定时间、形成时间等加工品质性状进行了分析,以期明确易位系小麦对加工品质性状影响的机理.结果表明,易位系小麦品种的醇溶蛋白和谷蛋白含量与非易位系品种相比存在显著差异,在沉淀值、稳定时间、形成时间等面筋质量性状上也存在显著差异.但两种蛋白的比例差异不显著.同时统计分析表明醇溶蛋白含量对易位系品种的品质影响较小,而谷蛋白含量,尤其是LMW含量,是影响1BL/1RS易位系品种加工品质变差的重要因素.     

CCD-二极管阵列分光光度法同时测定食品中的维生素B1和维生素B2

为建立一种同时测定食品中维生素B1和维生素B2的简单快速的方法，在氢氧化钠和碳酸氢钠混合溶液缓冲介质中，对氨基苯磺酸重氮盐与维生素B。发生偶氮反应，维生素B2不发生反应，采用电感耦合二极管阵列检测装置进行检测，用偏最小二乘法解析重叠光谱，从而实现了对食品中维生素B1、维生素B2的同时测定。方法的线性范围维生素B。和维生素B2分别为0～0.050mg/mL和0～0．10mg／mL；检出限分别为0．0072mg／mL和0．0085mg／mL。平均加标回收率维生素B1为87．3％～105．4％，维生素B2为90．0％～104．9％；相对标准偏差维生素B1为3．6％～9．1％，维生素B2为4．7～8．0％。该方法简单、快速、测定干扰小，结果与国家标准测定方法的差异无显性。     

冰结构蛋白对长期冻藏冷冻面团抗冻发酵特性与超微结构的影响

本实验采用质构分析仪、扫描电镜以及冷冻面团烘焙发酵试验法研究了冰结构蛋白（ISP）对长期冻藏冷冻面团抗冻发酵特性与超微结构的影响。结果发现：将面团在-18℃冻藏0、35、70、105d后,随冻藏时间延长,面团醒发时间延长,面包比容减小。添加0．5％ISP的面凼,经105d冻藏后,醒发时间由153min缩短到130min,缩短了15．0％;面包比容由4．05ml／g上升到4．71ml／g,上升了16.3％,并且ISP使面包硬度有所减小。扫描电镜实验表明：强化0．5％ISP的冷冻面团,经过105d的冻藏后,仍然可以观察到明显的面筋网络结构,这说明ISP可以显著保护冷冻面凼超微结构。     

不同细度黄精粉对面团流变学特性的影响

制备2种细度（100目／180目、180H／-）的黄精粉，按照设置的梯度分别添加到1#和2#面粉中．测定面团的流变学特定指标。结果表明。随着黄精粉添加量的增加．1栉粉的稳定时间逐渐缩短．R5抗张、12min弱化度增大，吸水率下降，拉伸度逐渐缩短。但低于3．0％的添加量，上述影响并不明显；2#粉在180目／一黄精粉条件下，随着黄精粉添加量的增加面团的稳定时间延长，12min弱化度无降低，     

金标免疫层析法检测黄曲霉毒素B1的方法

应用金标免疫层析法（GICA）研制的金标免疫试纸条对食品中黄曲霉毒素B1的检测，来确立该方法的各项技术指标。结果表明：方法的最低检测限：2．5ng／mL；金标免疫试纸条在4℃环境下可稳定10个月以上；与类似毒素AFB2、AFG2的交叉反应率分别是7，14％、6，25％；检测时间小于15min；GICA与ELISA方法的符合率达90％以上。该方法简便、快速，有较高的灵敏度，重复性好，特异性强，能定性或半定量检测食品中的黄曲霉毒素B1含量。     

黑麦酒精生产技术的研讨

探索出适合黑麦为原料生产酒精的工艺要点：1．使用新型液化酶，用量为8～10u/g淀粉；2．粉碎粒度60％～70％；3．拌料浓度28％～30％；拌料温度45℃左右；4．选用高活性干酵母；5．提高离心机转速，控制酒糟水回流量等。     

粤糖60号在金光农场新植品比试验结果初报

在金光农场蔗区进行品种比较试验，结果表明，粤糖60号新植蔗茎产量为125445kg／hm2，比对照种ROC22增产17．3％；含糖量达18900kg／hm2，比ROC22增产糖25．6％；11月、12月蔗糖分为14．10％和16．04％，比ROC22高0．70个百分点和1．28个百分点，增产、增糖幅度较大。该品种全生长...     

树头发的成分分析

采用反相高效液相色谱法、葸酮比色法分别对树头发的氨基酸、水溶性维生素、町济性糖等成分进行分析。结果表明，除色氨酸被水解破坏而未检出外，树头发蛋白中含有16种氨基酸，9种必需氨基酸，其氨基酸的总含量达179．652μg／mg，总必需氨基酸含量为63．546μg／mg，必需氨基酸含量占总含量的35．37％；树头发中可溶性糖含量为2．93％，粗纤维含量为7．55％，维生素的含量：维生素C 1．484mg／g，烟酸1．096mg／g，维生素B1 0．586mg／g，维生素B2 0．096mg／g．     

小麦蛋白质组分与面团特性和烘焙品质关系的研究

选用关中地区３０个小麦品种（系）为材料，对蛋白质组分与面团特性的关系进行了系统分析。结果表明：蛋白质组分对面团特性和烘焙品质有重要影响。麦醇蛋白和麦谷蛋白与沉淀值的关系十分密切。面团吸水率主要受麦醇蛋白的影响；面团形成时间，稳定时间，耐揉指数以及评价值与谷蛋白的关系更为密切。面团延伸度主要受麦醇蛋白影响；面团拉伸阻力、最大拉伸阻力和拉伸面积与谷蛋白关系密切。     

在喷气织机上开发特细高密直贡缎

我厂1994年引进了毕加诺DELTA－190型喷气织机50台，为发挥先进设备的效能，我厂在市场调研的基础上，开发了一种具有独特风格的特细高密直贡缎T／R（65／35）120Ne／2×120Ne／2163×150160cm（5枚3飞）。该产品广受客户青睐．市场前景广阔。1织物规格织物组织地4／1／，边2／2纬重平；织物幅宽160cm；原料T／R（65／35）；经纬纱号数9．84／2×9．84／2tex；经纬纱密度660×600根／10cm；总紧度766％、69．6％、92．9％。2品种特点该产品是5枚3飞经面缎，纹路清晰，布面丰满柔软，悬垂性好．光泽好，染色后色泽鲜艳，是理想的高级时…     

Origin and practical significance of the sticky dough factor in 1BL/1RS wheats

When translocated into wheat, the short arm of the 1R chromosome of rye carries with it linked resistance genes to powdery mildew, stripe rust, leaf rust and stem rust. The translocation is also reported to increase yield potential of hard wheats. However, many doughs made from some 1BL/1RS hard wheats are unacceptable for breadmaking purposes because of excessive stickiness and mixing intolerance. 1BL/1RS wheats may be sticky because of: the inheritance of secalin proteins from rye and absence of key glutenin subunits; higher amounts and/or differences in the composition of cell wall polysaccharides, β‐glucans and pentosans; and/or the presence of a ferulic acid ester moiety residing with the water‐soluble fraction of 1BL/1RS flours. None of these hypotheses has been proven or disproven, to date, as a cause of excessive stickiness. Investigators have found that 1BL/1RS doughs are not uniformly sticky and are in some instances less sticky than non‐1BL/1RS doughs. Significant genotype–environment interactions have been reported for dough stickiness and flour quality characteristics of 1BL/1RS wheats. Investigators have generally failed to find significant differences in the breadmaking performance of 1BL/1RS and non‐1BL/1RS hard wheats despite a report that 1BL/1RS doughs break down and soften during high‐speed mixing. The 1BL/1RS translocation has been shown to reduce cookie spread of soft wheat flours but has no deleterious effects on cake volume or texture. © 2002 Society of Chemical Industry     

小麦面团粘度影响因素研究进展

该文介绍国内外对小麦面团粘度影响因素研究进展;粘度是由面团粘结特性和内聚特性所共同决定一种特性,粘度过大会造成生产中断,且最终产品质量也会有所降低;麦谷蛋白及醇溶蛋白比例及结构、戊聚糖、1BL／1RS易位均对面团粘度产生影响。     

Cell wall composition of 1B/1R translocation wheat grains

The cell wall composition and total dietary fibre content of 12 different winter wheat cultivars both without and with 1B/1R gene were analysed. Translocation wheat (with 1B/1R gene) had higher contents of extractable xylose and unextractable mannose residues than standard wheat (without 1B/1R gene). Three sieved flours of standard wheat, translocation wheat and rye respectively were used for further detailed studies. Water‐extractable arabinoxylan was isolated and fractionated on a DEAE‐cellulose column. The water‐eluted fraction of translocation wheat had a higher proportion of monosubstituted xylose residues than the same fraction of standard wheat, which is a typical feature of rye arabinoxylan. Molecular weight determination showed that rye water‐eluted arabinoxylans were larger than those of wheat. The molecular weight of translocation wheat arabinoxylan was lower than that of standard wheat and had a high polydispersity. Xylanase‐resistant arabinoxylan was extracted from all three flours, and NMR studies showed that wheat xylanase‐resistant arabinoxylan had a lower amount of monosubstituted xylose residues, while the rye fraction was rich in consecutive disubstituted xylose residues. Translocation wheat xylanase‐resistant arabinoxylan resembled that of standard wheat. © 2002 Society of Chemical Industry     

Wheat Flour Compound that Produces Sticky Dough: Isolation and Identification

Some wheats have a 1B/1R translocation and may produce flours that give sticky doughs, even with optimum mixing time and water absorption. Studies showed that the water-soluble fraction caused sticky dough. Dialysis experiments indicated that the responsible substance had low molecular weight. Ionic exchange showed it to be either neutral or negatively charged. Gel filtration chromatography indicated it was both carbohydrate and UV-absorbing. Saponification caused it to lose ability to cause sticky dough. The UV-absorbing material and the carbohydrate had to be linked for the compound to be active. HPLC mass spectrometry indicated the UV-absorbing fraction was ferulic acid and the carbohydrate was a hexose.     

Effects of enzymes in fibre-enriched baking

The aim of the present study was to improve the quality of fibre-enriched wheat breads by enzymic treatment of the fibre fraction. The suitability of different enzymes in fibre-enriched baking and their effects on the dietary fibre content and the ratio of insoluble: soluble fibre content of the breads were studied. The enzyme preparations used were a hemicellulolytic culture filtrate of Trichoderma reesei, a specific (pI 9) xylanase of T reesei and Fermizyme, an α-amylase preparation containing a standardised level of hemicellulase activity. Rye bran was extracted in water (10% (w/w) suspension) to determine the solubilities of the β-glucans and pentosans. Addition of T reesei culture filtrate significantly increased the amount of extractable pentosan obtained from nonautoclaved rye bran. Rye bran supplementation (5%) of wheat flour increased the farinograph absorption and dough development time, but had little or no effect on stability and softening of the dough. The added enzymes decreased dough stability and increased softening. Addition of enzymes caused significant differences in the stickiness of the wheat doughs both with (P<0·003) and without (P<0·001) rye bran. Fermizyme significantly increased the stickiness of wheat doughs both with and without rye bran. The baking results of the fibre-enriched breads were improved by the added enzymes. Addition of T reesei culture filtrate increased the specific volume of the wheat breads both with and without rye bran by almost 20%. Enzyme mixtures were more efficient than individual xylanase in softening the bread crumb and reducing the staling rate of wheat breads both with and without rye bran. Incorporation of enzymes reduced the total dietary fibre content of the breads, but at least doubled the amount of soluble pentosan. The proportions of fluorescent cell walls in the breads were detected by microscopical image analysis. Enzyme addition caused the surface area of insoluble cell walls originating from wheat flours to decrease, suggesting that the enzymes exert more effects on wheat endorsperm cell walls than on bran particles. © 1998 SCI.     

Effect of Flour Extraction Rate and Baking on Thiamine and Riboflavin Content and Antioxidant Capacity of Traditional Rye Bread

ABSTRACT:  The effect of rye flour extraction rates and baking on thiamine and riboflavin content, and antioxidant capacity of traditional rye bread were studied and compared with white wheat flour. The content of thiamine was higher (10.9%) in rye dough formulated with dark rye flour (F-100%; extraction rate of 100%) than in rye dough formulated with brown rye flour (F-92%; extraction rate of 92%) that was similar to dough made with wheat flour. The riboflavin content in rye dough made from flour F-100% was also higher (16%) than in dough formulated with flour F-92%, and both provided larger riboflavin content than wheat dough. Baking led to reductions in thiamine of 56% for wheat bread and of 20% for both rye breads; however, this process caused only a 10% decrease in riboflavin for wheat bread and a 30% decrease for rye breads. Trolox equivalent antioxidant capacity, peroxyl radical scavenging capacity, DPPH radical scavenging activity, and Folin–Ciocalteu reducing capacity were higher in rye than in wheat dough and bread. Baking process produced slight changes in antioxidant activity, except for Superoxide Dismutase-like activity where a sharp decrease was observed. Our findings showed that rye breads are an important source of B vitamins and rye breads formulated with dark and brown flours showed better antioxidant properties than wheat bread. Therefore, rye breads should be more widely recommended in human nutrition.     

Comparative studies of the Osborne protein fraction of wheat varieties with different dough and baking properties]

The proteins of flours from the wheat varieties Clement (CLE) and Disponent (DIS), which are characterized by substitution of the wheat chromosome 1B by the rye chromosome 1R (CLE) and by 1BL/1RS-translocation of chromosome segments (DIS), respectively, and which yield sticky doughs, were extracted by the Osborne procedure and compared with the good variety Kolibri (KOL). CLE and DIS delivered significantly higher amounts of water-soluble proteins (31.2 and 23.2% of the total protein) than KOL (15.5%). The proportions of ethanol-soluble proteins were approximately constant for the three varieties (31.5-33.9%) while the amounts of residual proteins after extraction with ethanol were significantly different (CLE, 16.8%; DIS, 21.6%; KOL, 26.4%). Water extracts as well as residues exhibited also marked differences in their amino acid compositions. Investigation of the water extract from DIS by gel permeation chromatography and by RP-HPLC showed the presence of prolamins: omega 1,2-gliadins and/or omega-secalins could be detected on the basis of amino acid composition and N-terminal amino acid sequence. In the case of good varieties such as KOL, these prolamins seem to remain partially in the residue of the ethanol extract under the conditions of the classical Osborne procedure, whereas they are found in the water extract in the case of such varieties as CLE and DIS. On the other hand, a modified Osborne procedure (salt/ethanol/acetic acid) delivered the prolamins, which correspond to 39-40% of the total protein, completely within the ethanol fraction in the case of all three varieties.(ABSTRACT TRUNCATED AT 250 WORDS)     

Impact of sodium chloride on wheat flour dough for yeast‐leavened products. I. Rheological attributes

BACKGROUND: The rheological properties of wheat dough for yeast‐leavened products were tested at different levels of sodium chloride (NaCl) addition ranging from 0 to 40 g NaCl kg^?1 wheat flour. Rheological tests carried out to make this evaluation included (1) empirical rheological methods of the Farinograph, load extension and a dough stickiness test and (2) fundamental rheological methods of creep recovery and dynamic rheometry. Modifications to the gluten matrix microstructure by NaCl were examined by confocal laser‐scanning microscopy. RESULTS: Highly significant (P?0.001) differences due to NaCl addition could be determined in particular by the stickiness test as well as by examination of the creep test with the Burger model. Rheological changes measured in the creep test probably depend on protein charge shielding due to NaCl interaction, resulting in an improvement in gluten network formation. An increase in dough stickiness was measured when using NaCl. CONCLUSION: The present result for stickiness is contrary to the common subjective results. Therefore the theory proposed here for increased stickiness suggests that it is based on more non‐protein‐bound water in the dough system due to NaCl interaction and thus more viscous dough behaviour, which leads to higher stickiness as measured with the stickiness test. This may also suggest that the objectively measured ‘stickiness’ in this case does not properly indicate the subjectively measured stickiness it was designed to represent. Copyright © 2011 Society of Chemical Industry     

Effect of sourdough processing and baking on the content of enniatins and beauvericin in wheat and rye bread

The occurrence of the emerging mycotoxins enniatins (ENNs) and beauvericin (BEA) has been reported in Fusarium-infected cereals. To study the effect of sourdough processing and baking on ENN B, ENN B1, and BEA concentrations, a recently developed stable isotope dilution assay for these mycotoxins was used. After milling of wheat and rye grains naturally contaminated with ENN B and ENN B1, approximately 70–82 % of the two ENNs were found in the bran fraction and the rest remained in flour. BEA was added to flour before sourdough fermentation. In an experiment on a microscale, dough was fermented for 24 h at 30 or 40 °C, which reduced part of the ENNs and BEA in particular at 40 °C. On a standard scale, mixing, resting, and proofing of the bread dough resulted in 13–19 % reduction of the ENNs compared with flour, but in no significant change of BEA. The final baking at 200 °C for 25 min led to a further decrease of the ENNs and BEA, ranging from 9 to 28 % compared with fermented dough. In case of rye sourdough bread, greater reductions of ENNs were found in crust than in crumb. For both wheat and rye flours, overall 25–41 % of ENN B, ENN B1, and BEA were reduced during the whole sourdough bread-making process.     

The chemistry of bread making: The role of salt to ensure optimal functionality of its constituents

Large consumptions of dietary sodium have been shown to lead to hypertension, one of the main causative factors in cardiovascular disease. Bread (and other cereal products) accounts for ~30% of the overall sodium intake in our diet; therefore, industry has been developing strategies to significantly reduce its usage. However, at reduced sodium levels, dough handling can be affected due to sticky dough phenomena creating major processing issues and a poor quality final product. It is hypothesized that the formation of a strong gluten network plays a crucial role in developing nonsticky dough, a process that is strengthened in the presence of NaCl. However, at low NaCl levels, a weaker gluten network forms resulting in the prevalence of other wheat flours’ constituents impact on water mobility within the dough to contribute to the stickiness phenomenon. This review discusses the underlying mechanisms that can influence the formation of sticky dough within a low sodium environment and discusses strategies used to help circumvent them.