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Anette Moldestad Bernt Hoel Ulrike Böcker Shiori Koga Ellen Færgestad Mosleth Anne Kjersti Uhlen 《Journal of Cereal Science》2014
The aim of this study was to investigate effects of temperature during grain filling on gluten quality characteristics at a lower to moderate temperature range. Experiments with two wheat varieties grown in field covered by polypropylene tunnels during grain filling were performed in two seasons. Mean day temperature differences achieved within the tunnel were approximately 2–2.5 °C from the open to the closed end. There were significant effects of temperature on grain maturity time, thousand grain weight and protein content. The resistance to stretching of the gluten doughs increased with the increasing day temperatures. This was reflected in the proportion of unextractable polymeric proteins (UPP). The results suggest that increases in temperature within this temperature range affect the polymerization of polymeric proteins, giving higher molecular weights, and hence increased Rmax and stronger gluten. The two varieties differed in their response to temperature. In addition, there were seasonal variations in gluten functionality that may be associated with fluctuations in day temperatures between the seasons. 相似文献
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Ahmad Asoodeh Leyla Haghighi Jamashidkhan Chamani Mohamad Amin Ansari-Ogholbeyk Zahra Mojallal-Tabatabaei Milad Lagzian 《Journal of Cereal Science》2014
The present study was carried out to characterize ACE inhibitory peptides which are released from the trypsin hydrolysate of wheat gluten protein. In silico proteolitic digestion of a high molecular weight glutenin subunit was performed. Among the resultant fragments, four peptides were selected for chemical synthesis based on the chemoinformatics studies and docking properties. The ACE inhibitory activity and kinetic parameters of the most important peptides were determined. Molecular docking simulation was also performed to predict the sites on ACE in which these peptides bind and displayed inhibition mechanisms. Two peptide sequences of IPALLKR (P4) and AQQLAAQLPAMCR (P6) showed higher ACE inhibitory activity among peptide collection. The IC50 values of P6 and P4 were 43 ± 1.3 μM and 68 ± 2.8 μM, respectively. P6 peptide was proved to be a more potent ACE inhibitor than P4 peptide. Lineweaver-Burk plots revealed that P6 and P4 behaved as non-competitive and competitive ACE inhibitors, respectively. The simulations showed that P4 bound to the active site region. Conversely, P6 bound to the N-terminus entrance of substrate tunnel and obstructed the substrate access into the catalytic site. Overall, the results showed that these peptides would be considered as a model for discovering new bio-compatible ACE inhibitors. 相似文献
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Quantitative proteomic analysis of wheat grain proteins reveals differential effects of silencing of omega-5 gliadin genes in transgenic lines 总被引：1，自引：0，他引：1
Novel wheat lines with altered flour compositions can be used to decipher the roles of specific gluten proteins in flour quality. Grain proteins from transgenic wheat lines in which genes encoding the omega-5 gliadins were silenced by RNA interference (RNAi) were analyzed by quantitative 2-dimensional gel electrophoresis (2-DE). The precise effects of the genetic modifications on the proteome were assessed in four homozygous lines generated with the same RNAi construct. Two of the lines showed >80% decreases in omega-5 gliadins with only small changes in the levels of other gluten proteins. In the other two lines, omega-5 gliadins were not detectable by 2-DE. However, there were notable reductions in all omega-1,2 gliadins. Small decreases in several other gluten proteins were also detected in one of the lines. The other line showed notable decreases in three HMW-GS and an s-type LMW-GS, increases in two m-type LMW-GS and several alpha gliadins, as well as increases in both serpins and triticin. The study demonstrates that the same RNAi construct can have differential effects on the wheat grain proteome and highlights the importance of detailed proteomic analyses of transgenic grain prior to selecting lines for further assessment of flour quality and allergenic potential. 相似文献
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化学合成面筋蛋白外啡肽B5对鸡淋巴细胞体外免疫活性的影响 总被引：1，自引：0，他引：1
面筋蛋白外啡肽B5是一种通过面筋蛋白的体外酶解所获得的阿片肽,具有一定的免疫学功能,有望成为一新型免疫增强剂。本研究通过化学合成方法制备,并将其加入鸡外周血单个核细胞中,以观察其对淋巴细胞的增殖效应和对IFN-γ和IL-4mRNA水平影响。结果显示,化学合成获得了高纯度的外啡肽B5(HPLC质量分数大于98.435 7%);外啡肽B5能显著促进鸡淋巴细胞的增殖,并能显著提高IFN-γ的mRNA水平(P0.05),对IL-4mRNA无显著影响。 相似文献
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Bread-making quality of wheat flour is largely determined by the accumulation, concentration and composition of the proteins in the grain, which are influenced by genetic (G) and environment (E) variation and their interactions. We have therefore evaluated the importance of G and E factors and their interactions in determining the accumulation and composition of the proteins in the wheat grain. The cultivar determined development time (CDDT), together with the amount and timing of N application, played a significant role in determining the accumulation and final composition of the wheat grain proteins, explaining 21–59% of the variation. At low temperature, N application both at spike formation and at anthesis explained the highest proportion of variation (36%) in the percentage of sodium dodecyl sulphate (SDS) unextractable polymers in the total amount of polymers (% UPP), while at high temperature CDDT contributed most to the variation in % UPP (20%). The largest contributor to variation in the amount of total SDS extractable proteins (TOTE) was N application at anthesis, both at low and high temperatures (12% and 36%, respectively). Thus, the climate should be considered in recommendations for improving the protein quality and thereby the bread-making quality of wheat. 相似文献
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Enzymatic hydrolysis at increased solid concentrations is beneficial with regard to energy and water consumption. This study examines the influence of the solid concentration on the enzymatic hydrolysis of wheat gluten and the resulting functional properties of the hydrolysate. Wheat gluten was mildly hydrolyzed at a solid concentration varying from 10% to 60% to degrees of hydrolysis (DH%) ranging from 3.2% to 10.2%. The gluten was susceptible to hydrolysis at all solid concentrations but the hydrolysis rate was influenced by increasing solid concentrations. Size-exclusion high-performance liquid chromatography revealed an increase in the ratio of peptides with a molecular mass >25 kDa for solid concentrations of 40% and 60%. The water solubility increased on hydrolysis and was independent of the solid concentration during proteolysis. The foam stability was not influenced by the solid concentration at low DH%. At DH% higher than 8%, high solid concentrations increased the foam stability, which might be related to the presence of more peptides with a molecular mass >25 kDa. In addition, we found increased reactor productivity. The results show the potential of hydrolyzing wheat gluten at high solid concentrations, which could lead to large savings for water and energy when applied industrially. 相似文献
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The breadmaking quality of wheat is affected by the composition of gluten proteins and the polymerisation of subunits that are synthesised and accumulated in developing wheat grain. The biological mechanisms and time course of these events during grain development are documented, but not widely confirmed. Therefore, the aim of this study was to monitor the accumulation of gluten protein subunits and the size distribution of protein aggregates during grain development. The effect of desiccation on the polymerisation of gluten proteins and the functional properties of gluten were also studied. The results showed that the size of glutenin polymers remained consistently low until yellow ripeness (YR), while it increased during grain desiccation after YR. Hence, this polymerisation process was presumed to be initiated by desiccation. A similar polymerisation event was also observed when premature grains were dried artificially. The composition of gluten proteins, the ratios of glutenin to gliadin and high molecular weight-glutenin subunits to low molecular weight-glutenin subunits, in premature grain after artificial desiccation showed close association with the size of glutenin polymers in artificially dried grain. Functional properties of gluten in these samples were also associated with polymer size after artificial desiccation. 相似文献
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The effects of reduced headspace pressure on the development of gluten network in doughs made from both high-protein flour (HPF) and low-protein flour (LPF) were investigated. The effect of vacuum mixing was found to be dependent on both flour-type and mixing-time. A significant increase in dough extensibility was observed when the HPF dough was mixed under moderate vacuum of −0.04 MPa for 3 min as compared to the one mixed under atmospheric pressure for the same duration. This was attributed to the formation of a more extensive gluten network associated with an increased disulphide bond density and a significantly higher β-sheet to β-turn ratio. On the other hand, over-mixing was observed in the LPF dough that was mixed for 5 min under atmospheric pressure. Applying moderate vacuum of −0.04 MPa allowed the LPF dough to withstand longer mixing time, as indicated by its increased disulphide bond density and biaxial extensibility compared to the control dough mixed under atmospheric pressure. Results of this study suggest the potential of applying vacuum to reduce the mixing time required for high protein flour and to prevent the over-mixing of low protein flour. 相似文献