基因型和环境对面团流变学特性的影响研究     

邓志英  田纪春  孙彩玲  张永祥  胡瑞波 《勤云标准版测试》2005,(3)

用揉混仪和质构仪研究了3个不同品质类型的冬小麦品种在8个不同的生长环境条件下的面团流变学特性,分析了基因型和环境对性状的影响及各性状间的相关性。结果表明:面团流变学特性受基因型(G)和环境(E)及其互作的共同作用,其中基因型方差均值>环境方差均值>G×E互作均值;从性状的表现看,基因型以济麦20表现最佳,环境以烟台点综合表现最好;相关分析表明,面团粘度性状与最大拉伸阻力、拉伸比、峰值时间、峰值面积和8min带宽呈显著负相关,而与延伸度呈显著正相关。最大拉伸阻力与峰值时间、峰值面积和8min带宽呈显著正相关。因此,进行品质评价时,可用质构仪测定的面团粘度特性对面团品质进行初步快速的评定。  相似文献   

Physicochemical and Antimicrobial Properties of Thermosensitive Chitosan Hydrogel Loaded with Fosfomycin     

Luke J. Tucker  Christine S. Grant  Malley A. Gautreaux  Dhanush L. Amarasekara  Nicholas C. Fitzkee  Amol V. Janorkar  Anandavalli Varadarajan  Santanu Kundu  Lauren B. Priddy 《Marine drugs》2021,19(3)

Thermosensitive chitosan hydrogels—renewable, biocompatible materials—have many applications as injectable biomaterials for localized drug delivery in the treatment of a variety of diseases. To combat infections such as Staphylococcus aureus osteomyelitis, localized antibiotic delivery would allow for higher doses at the site of infection without the risks associated with traditional antibiotic regimens. Fosfomycin, a small antibiotic in its own class, was loaded into a chitosan hydrogel system with varied beta-glycerol phosphate (β-GP) and fosfomycin (FOS) concentrations. The purpose of this study was to elucidate the interactions between FOS and chitosan hydrogel. The Kirby Bauer assay revealed an unexpected concentration-dependent inhibition of S. aureus, with reduced efficacy at the high FOS concentration but only at the low β-GP concentration. No effect of FOS concentration was observed for the planktonic assay. Rheological testing revealed that increasing β-GP concentration increased the storage modulus while decreasing gelation temperature. NMR showed that FOS was removed from the liquid portion of the hydrogel by reaction over 12 h. SEM and FTIR confirmed gels degraded and released organophosphates over 5 days. This work provides insight into the physicochemical interactions between fosfomycin and chitosan hydrogel systems and informs selection of biomaterial components for improving infection treatment.  相似文献   

Semi-sweet biscuit making potential of soft wheat flour patent,middle-cut and clear mill streams made with native and reconstituted flours     

P. Fustier  F. Castaigne  S.L. Turgeon  C.G. Biliaderis 《Journal of Cereal Science》2007

The influence of patent, middle-cut and clear flour grades as native or reconstituted flour blends on both the rheological properties of the dough and the quality of semi-sweet biscuit (flour/sugar/fat/water ratio of 100/30/8/36) was studied. Moving from the central portion (patent) to the peripheral portion (clear) of the grain endosperm increased the dough hardness from 3.77 to 4.84 N, consistency from 19.3 to 25.5 N s, elongational viscosity from 4.13×10⁻⁵ to 5.54×10⁻⁵ Pa s, half-relaxation time from 0.45 to 0.59 s, but decreased the rate of relaxation from 4.51 to 3.09 s⁻¹ of the biscuit's dough produced with the native flours due to the wide variation in the physico-chemical properties of these fractions. Quantitatively, the fractionation/reconstitution procedure reduced moderately these rheological parameters, and the flour functionality could not be restored completely. Biscuits produced with the patent flour showed the largest length and lowest thickness, whilst the clear fraction led to production of denser biscuits with greater cohesion (mean tearing force) of the biscuit inner structure and also contain more grains or group of grains per unit of penetration (number of spatial ruptures). The biscuits made with the reconstituted flour fractions had almost equivalent dimensional characteristics, and excellent surface appearance, but were also darker in colour than their native flour counterparts.  相似文献   

小麦子粒湿面筋FT-NIRS分析模型的建立与研究     

雷加容  余敖  欧俊梅  任勇  李生荣  杜小英  陶军  周强 《安徽农学通报》2015,(6):30-31

用傅立叶变换近红外光谱(FT-NIRS)分析小麦子粒湿面筋含量。采用国标GB/T14608-1993法测试了216份小麦子粒的湿面筋含量,用近红外仪采集数据,选择113份建立了数学模型。结果:最佳主成分数(Rank)=3,内部交叉验证均方差(RMSECV)=2.33,决定系数(R2)=90.69。为了验证模型的可靠性,对预测集样品进行预测,结果湿面筋的预测均方差(RMSEP)=2.70;相对偏差(RSEP,%)=11.84。结果表明,该数学模型可初步用来快速、较准确、无污染、低消耗地测试小麦子粒的湿面筋含量。  相似文献   

Effect of heat on rheology of gluten fractions from flours with different bread-making quality     

Costas E. Stathopoulos  Amalia A. Tsiami  Bodgan J. Dobraszczyk  J. David Schofield 《Journal of Cereal Science》2006,43(3):322-330

Flours from wheat varieties of differing bread-making quality were fractionated using a sequential salt precipitation technique. The gluten fractions in the different varieties varied in the proportion of HMW, LMW glutenins and gliadins. Their rheological behaviour was examined using constant strain (2%) small deformation oscillation tests over frequencies ranging from 0.005 to 10 Hz, before and after heating at 90 °C. The fractions containing a higher proportion of HMW glutenins were associated with a predominantly elastic character, whereas fractions containing mostly gliadins exhibited a viscous-like behaviour. The frequency dependent rheological behaviour of fractions containing HMW proteins was less susceptible to heat, and their elastic character was maintained after heating, whereas the rheology of intermediate fractions and fractions containing mostly gliadins was more susceptible to heating, indicating a rapid change from viscous to elastic behaviour after heating.  相似文献   

The low-molecular-weight glutenin subunits of wheat gluten   总被引：11，自引：0，他引：11  

Renato D'Ovidio  Stefania Masci 《Journal of Cereal Science》2004,39(3):321-339

Low-molecular-weight glutenin subunits (LMW-GS) are polymeric protein components of wheat endosperm and like all seed storage proteins, are digested to provide nutrients for the embryo during seed germination and seedling growth. Due to their structural characteristics, they exhibit features important for the technological properties of wheat flour. Their ability to form inter-molecular disulphide bonds with each other and/or with high-molecular-weight glutenin subunits (HMW-GS), is important for the formation of the glutenin polymers, which are among the biggest macromolecules present in nature, and determine the processing properties of wheat dough. Explanation of the structural basis for these correlations continues to intrigue researchers and, while earlier emphasis had been on HMW-GS, considerable attention is now being focused on the LMW-GS.LMW-GS are a highly polymorphic protein complex, including proteins with gliadin-type sequences. Difficulty in separating single components, arising from the complexity of the group, has limited the characterisation of the individual proteins and the establishment of clear-cut relationships with quality parameters.Here we review results concerning different aspects of LMW-GS, including their structural characteristics, genetic control, and relationships with quality parameters. In addition, we emphasise the distinction between the components with sequences unique to the LMW-GS fraction and those behaving like glutenin subunits (incorporated into polymers), but with sequences corresponding to gliadins.  相似文献   

Molecular mobility in model dough systems studied by time-domain nuclear magnetic resonance spectroscopy   总被引：3，自引：0，他引：3  

C.J. Doona  Moo-Yeol Baik   《Journal of Cereal Science》2007,45(3):257-262

The microscopic distribution and dynamic state of water and molecular mobility in various model systems are investigated using time-domain NMR spectroscopy. Starch and gluten showed different continuous distribution populations in T₂₁ (μsec range, obtained from One pulse experiments) and T₂₂ (msec range, obtained from CPMG experiments) proving that starch and gluten have different water dynamics and molecular mobility. A starch/gluten mixture (76:12, w/w) and wheat flour dough exhibited similar patterns indicating that water and molecular mobilities in dough tended to be more representative of interactions with starch than gluten, even though both water–starch and water–gluten interactions are occurring in wheat flour dough. Increasing the water content did not influence the continuous distribution pattern of T₂₁ but affected the relative amount of each fraction in T₂₁ (i.e. an increase of the more mobile fraction and a decrease of the less mobile fraction with increasing moisture). Added water has an important role in the more mobile fraction but not in the less mobile fraction, which is in μs range. This indicates that model food systems contain multiple microstructural domains with various water and molecular mobilities that show correspondingly different water dynamics. Therefore, the dispersion of various relaxation time constants helped identify the distribution of independent microstructural domains. The manipulation of the composition of the model food system influences the water dynamics and molecular mobility and provides a basis for the application of the microstructural domain concept to real food systems.  相似文献   

竹粉/聚丙烯发泡复合材料的增韧效果   总被引：6，自引：6，他引：0  

周吓星  陈礼辉  林巧佳 《农业工程学报》2013,29(2):266-272

为研发可代替聚丙烯(polypropylene,PP)应用于汽车内饰件的木塑复合材料,减少白色污染,节约化石能源,同时提高木塑复合材料的附加值,拓宽其应用领域。该文以注塑法制备竹粉/聚丙烯发泡复合材料,并分别采用乙烯-1-辛烯共聚物(polyolefin elastomer,POE)和马来酸酐接枝POE(maleic anhydride grafted polyolefin elastomer,POE-g-MAH)增韧复合材料。研究了增韧填料对发泡复合材料力学性能的影响,用环境扫描电镜(environmental scanning electronic microscopy,ESEM)对复合材料的冲击断面进行观察,并进行了频率扫描的动态流变测试。结果表明:添加POE和POE-g-MAH在略微降低材料拉伸和弯曲强度的同时,可明显提高材料的缺口冲击强度,二者最佳用量分别为15%和8%;8%POE-g-MAH增韧的复合材料的缺口冲击强度为8.55kJ/m2,提高了35.7%,可很好地应用于汽车内饰件。ESEM显示,增韧后,复合材料的断裂形式转变为韧性断裂。动态频率扫描结果显示,POE对复合材料流变性能的影响较小,而POE-g-MAH增韧的复合材料的储能模量和复数黏度明显增大,且"第二平台"现象更为明显。  相似文献   

2种糊化方式对小麦面粉流变及回生特性影响的比较   总被引：2，自引：0，他引：2  

CHEN Wei  陈卫  范大明  赵建新  田丰伟  邓娟  张灏 《吉林农业大学学报》2008,30(6)

对传统加热糊化和微波糊化小麦面浆的过程进行了比较。在相同反应温度与时间的条件下,分别考察体系的糊化特性、流变学特性、贮藏回生特性及其回生后的超微结构。结果表明：小麦面粉经微波糊化后体系均匀、黏度较大、剪切恢复性小、超微结构致密,传统加热糊化不充分、体系黏度较低、存在剪切恢复性、超微结构不均匀;微波糊化只能在短时间内延缓淀粉体系的回生作用,不能降低其最终回生度。  相似文献   

Importance of extensional rheological properties on fiber-enriched corn extrudates     

Dhananjay A. Pai  Orane A. Blake  Bruce R. Hamaker  Osvaldo H. Campanella   《Journal of Cereal Science》2009,50(2):227-234

Incorporation of insoluble fibers into extruded cereals severely limits their expansion and reduces crispness. The specific objective of this work was to investigate how corn bran and its fractions mixed with cornmeal affect rheology and extrudate expansion. Alkali-treated bran (ATB) and alkaline-soluble bran (ASB) were prepared from unmodified corn bran (UMB). Mixtures of the different corn bran fractions and degermed cornmeal having a 26% (w/w) of total dietary fibers were extruded in a twin screw extruder and expansion of the extrudates was determined. Melt shear rheology of mixtures of cornmeal and different corn bran fractions having a 20% total dietary fiber was determined using a capillary rheometer at 120 °C while the extensional rheology was determined using lubricated squeezing flow. The expansion of extrudates containing ATB was larger than those containing UMB, while extrudates containing ASB showed a greater expansion that was close to that of the control. Addition of UMB to cornmeal increased shear and extensional viscosity significantly as compared to the control. ATB addition increased the shear viscosity of the mixture to a small extent but showed the highest extensional viscosity amongst the samples. Addition of ASB resulted in mixtures having lower shear and extensional viscosities than the control.  相似文献