Potential Utilization of Mixolab for Quality Evaluation of Bread Wheat Genotypes

The aim of this study was to determine the possibility of using Mixolab to assess the quality of different wheat genotypes. Mixolab data were compared with various flour quality characteristics and bread volume. The samples were chosen to represent a wide range in terms of grain and rheological properties and baking quality. There are eight paramaters used to evaluate a Mixolab curve. C1 and C2 are related to protein quality, whereas C3, C4 and C5 are related to the starch characteristics. Slopes α, β, γ are the indicators of protein weakening, starching speed, and enzymatic degradation. There were significant correlations between two Mixolab parameters (Stability and C2) and Zeleny sedimentation and Alveograph W values (P < 0.01). Some of the Mixolab parameters (C3, C4, C5) were correlated with Alveograph G and P/L value (P < 0.01). Mixolab values are generally in agreement with Farinograph values. There were significant negative correlations between most of the Mixolab parameters (Stability, C2, C3, C4) and Farinograph softening degree. Stability and C2 parameters of Mixolab were also significantly correlated with Farinograph stability values (P < 0.01). The correlation between Mixolab stability and Farinograph stability was considerably high (r = 0.907, P < 0.001). The Mixolab parameters C3, C4, and C5 were significantly correlated with bread volume. Significant correlations were observed between slope α and Zeleny sedimentation (P < 0.05), Alveograph W (P < 0.01), Farinograph softening degree (P < 0.001), and stability (P < 0.001) values.     

Characterization of Resistant Starch Samples Prepared from Two High‐Amylose Maize Starches Through Debranching and Heat Treatments

The aim of the present study was to investigate effects of debranching, autoclaving‐storing cycles, and drying processes (oven‐drying or freeze‐drying) on RS contents, thermal, pasting, and functional properties of high‐amylose maize starches (Hylon V and Hylon VII). The resistant starch (RS) contents increased (≤57.8%) with increasing autoclaving‐storing cycles. RS contents of oven‐dried samples were higher than those of freeze‐dried samples due to ongoing retrogradation of starch during oven drying at 50°C. Debranching caused a significant decrease in peak transition temperature and enthalpy values as compared with native starches. Solubility and water binding values of RS preparations were higher than those of native starches. Addition of native and autoclaved samples had improving effect on emulsion properties of albumin. Cold viscosity values of oven‐dried samples were lower as compared with freeze‐dried samples; this might be due to higher number of H‐bonds in the oven‐dried samples expected to be formed during drying. Debranching and autoclaving‐storing cycles caused decreases in peak, breakdown, and final viscosity values. The results of present study showed that debranching and heat treatments increased the RS contents and improved the functional properties of high‐amylose maize starches.     

阿克苏河流域平原型水库水质特征研究

本文对阿克苏流域的三座大型平原水库,即上游水库、胜利水库和多浪水库在枯水期和丰水期的水质进行了监测分析,比较了各水库不同水期水质现状,并对监测指标进行了因子分析。结果表明:三座水库枯水期污染程度比丰水期高。水质污染物可分抑制性因子(F1),包括NH3-N、SO42-、Cl-和矿化度以及富营养性污染指标(F2),包括TN、TP和CODMn。目前水库水质主要由第一因子F1决定。枯水期水质污染大小次序为胜利水库>上游水库>多浪水库,而丰水期为多浪水库>胜利水库>上游水库。三座水库水质与引水河流的水质污染指标之间存在极显著相关性。     

Ultrasonic Characterization of Unyeasted Bread Dough of Different Sodium Chloride Concentrations

Altering the properties of dough by reducing sodium chloride (NaCl) content affects aeration processes during mixing. The effect of NaCl concentration on the bubble size distribution (BSD) in unyeasted doughs was investigated by an ultrasonic transmission technique through analysis of frequency‐dependent ultrasonic phase velocity and attenuation coefficient. As NaCl concentration was decreased, the volume fraction of gas in the dough increased, resulting in a larger attenuation coefficient for the dough. From the peak in attenuation coefficient, estimates of the median radius and the width of the lognormal BSD in the dough were extracted, both of which were sensitive to the dough's NaCl concentration. As NaCl concentration was reduced, the bubble radius decreased and the width of the distribution increased, in accordance with expectations arising from changes in the dough's consistency. Over the course of 150 min, the radius increased (40–50%) and the width decreased (4–8%) for all dough formulations, consistent with changes in the BSD arising from disproportionation. These dynamic changes demonstrate that dough is an interesting soft material whose formulation can be manipulated to enable it to possess different BSDs; the diffusively driven evolution in these bubble sizes can be investigated noninvasively with ultrasound.     

Characterization of a glutenin-specific serine proteinase of Sunn bug Eurygaster integricepts Put

Glutenin hydrolyzing proteinases (GHPs) have been purified, by affinity chromatography, from wheat seeds damaged by the Sunn bug Eurygaster integriceps (Hemiptera, Scutelleridae). A 28 kDa protein was partially sequenced by mass spectrometry and Edman degradation which showed homology to serine proteases from various insects. Three full length clones were obtained from cDNA isolated from Sunn bug salivary glands using degenerate PCR based on the sequences obtained. The cleavage site of the protease was determined using recombinant and synthetic peptides and shown to be between the consensus hexapeptide and nonapeptide repeat motifs present in the high molecular weight subunits of wheat glutenin (PGQGQQ∧GYYPTSLQQ). Homology models were generated for the three proteinases identified in this study using the high resolution X-ray structure of a crayfish (Pontastacus leptodactylus) trypsin complexed with a peptide inhibitor as template (PDB accession 2F91). The novel specificity of this protease may find applications in both fundamental and applied studies.     

新疆细毛羊12种组织乳酸脱氢酶电泳初步研究

本文报道了新疆细毛羊12种组织的 LDH 的聚丙烯酰胺凝胶不连续电泳图谱,并对酶谱的区带数目、泳动率、相对含量及染色强度进行了分析比较。测定结果表明:12种组织的 LDH同工酶谱呈现明显的组织特异性。     

Detection of Irradiated Wheat Using the Electron Paramagnetic Resonance Spin Probe Technique

In this study, the electron paramagnetic resonance (EPR) spin probe technique is applied as a detection method in the differentiation of irradiated and unirradiated wheat seeds. Two wheat cultivars, Kunduru and Bezostaya, were used. Aqueous solutions of 4-hydroxy-TEMPO (TANOL) spin probe prepared with a line-broadening agent, potassium ferricyanide, were used in all experiments. The EPR spectra of the samples were recorded against time. A decrease in the signal intensity and a change in the shape of the intensity-time curve (rehydration curve) were observed, depending on the applied level of irradiation. The ratio of the lipid and aqueous regions at the high field (m_I = -1) line changes, depending on the dose of irradiation.     

Effects of Suni Bug (Eurygaster spp.) Damage on Milling Properties and Semolina Quality of Durum Wheats (Triticum durum L.)

Economic losses due to suni‐bug (Eurygaster spp. and Aelia spp.) damage are important for the cereal industry in East European and Middle East countries. Samples of five durum wheat cultivars (Diyarbakir, Firat, Ege, Svevo, and Zenith) with zero, medium, and high levels of suni‐bug damage were used to determine the effects of suni‐bug damage on milling properties and semolina quality. As the damage level increased, semolina yields of all cultivars decreased significantly. The loss of semolina yield was greater than decreases in total yield of semolina plus flour, indicating that semolina yields were affected to a higher extent than were flour yields. The ash contents of the semolina samples increased significantly in all cultivars with increasing suni‐bug damage. The falling number values were not correlated with suni‐bug damage level and amylase activities of all samples were quite low. The pasting properties did not differ to a great extent depending on the suni‐bug damage level. Gluten quality of semolina samples substantially deteriorated as suni‐bug damage level increased, as determined by SDS‐sedimentation and mixograph analyses. It was concluded that suni‐bug damage would decrease profits of durum wheat millers substantially by affecting semolina yield and quality.     

Effects of suni-bug (Eurygaster spp.) damage on semolina properties and spaghetti quality characteristics of durum wheats (Triticum durum L.)

Effects of suni-bug (Eurygaster spp.) damage on semolina properties and spaghetti quality characteristics of durum wheats (Triticum durum L.) were investigated. The semolinas obtained from sound (control), medium damage (around 20%) and high damage (around 40%) samples of five durum wheat cultivars (cvs. Diyarbakir, Firat, Ege, Svevo and Zenith) were processed into spaghetti. As the bug damage level increased, Glutograph stretch values of all cultivars decreased significantly probably due to deteriorative effects of bug damage on gluten quality. Glutograph relaxation values and gluten spread values of the damaged samples were considerably higher compared to those of sound samples in all cultivars, due to proteolytic degradation. The breaking force of the uncooked spaghetti samples decreased significantly with increasing bug damage level indicating that they were susceptible to breakage and not suitable for handling, packaging and shipment. Panel tests indicated significant deterioration in sensory properties (stickiness, firmness and bulkiness) generally at the medium damage level.