Rheological behavior

流变行为
  • 文章类型: Journal Article
    巴氏灭菌,作为食品加工的重要组成部分,Pickering乳液稳定性的调节越来越受到关注。在这项研究中,研究了巴氏杀菌和魔芋葡甘露聚糖(KGM)在Pickering乳液性能调节中的作用。结果表明,KGM形成的网络结构抑制了巴氏杀菌引起的液滴团聚,提高了Pickering乳液的热稳定性。KGM浓度的增加改善了其网络结构的致密化,如巴氏灭菌后乳液的粘弹性增强所证明的。在65°C巴氏灭菌30分钟后,包裹在Pickering乳液中的β-胡萝卜素的保留率可以达到99%。此外,巴氏杀菌进一步增强了KGM对游离脂肪酸释放的抑制作用,并实现了β-胡萝卜素的可控释放。该研究为构建用于递送温度敏感疏水成分的高度稳定的Pickering乳液提供了理论指导。
    Pasteurization, as a meaningful part of food processing, has received growing attention for regulating Pickering emulsion stability. In this research, the role of pasteurization and konjac glucomannan (KGM) in the modulation of Pickering emulsion properties was investigated. The results showed that the network structure formed by KGM inhibited the agglomeration of droplets due to pasteurization, which improved the heat stability of the Pickering emulsion. Increasing the concentration of KGM improved the densification of its network structure, as evidenced by the enhanced viscoelasticity of the emulsion after pasteurization. The retention rate of β-carotene encapsulated in the Pickering emulsion could reach 99% after pasteurization at 65 °C for 30 min. Moreover, pasteurization further enhanced the inhibitory effect of KGM on free fatty acid release and implemented a manageable release of β-carotene. This research offers theoretical guidance for the construction of highly stable Pickering emulsions for delivering temperature-sensitive hydrophobic ingredients.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    这项研究调查了超声(US)与κ-角叉菜胶(KC)的前后添加相结合对胶凝性能的影响,低盐条件下肌原纤维蛋白(MP)的结构特征和流变行为。结果表明,与单独使用US和单独使用KC处理的MP凝胶相比,US与KC的预添加或后添加组合提供了更高的MP凝胶强度和持水能力(WHC)(P<0.05)。US结合预先添加KC促进了MP和KC之间的结合,提高了混合MP凝胶的凝胶强度和WHC,并显着改善了MP的流变行为。最高的表面疏水性也证实了这一点,US与预先添加KC组合的MP凝胶的二硫键和β-折叠含量。此外,微观结构结果反映了KC与US组合的预添加的致密结构。然而,US与KC的后添加结合导致在复合凝胶中有限的MP解折叠和相对弱的疏水相互作用。这在改善MP凝胶的凝胶性质方面不太有效。本研究提供了通过应用US和KC增强低盐肉制品胶凝特性的潜在策略。
    This study investigated the effect of ultrasound (US) combined with pre- and post-addition of κ-carrageenan (KC) on the gelling properties, structural characteristics and rheological behavior of myofibrillar proteins (MP) under low-salt conditions. The results showed that US combined with either pre- or post-addition of KC rendered higher gel strength and water holding capacity (WHC) of MP gels than those treated with US alone and added with KC alone (P < 0.05). US combined with pre-addition of KC facilitated the binding between MP and KC, which enhanced the gel strength and WHC of the mixed MP gels and significantly improved the rheological behavior of MP. This was also confirmed by the highest surface hydrophobicity, disulfide bonds and β-sheet content of the MP gels with US combined with pre-addition of KC. Moreover, microstructural results reflected a denser structure for the pre-addition of KC in combination with US. However, US combined with post-addition of KC resulted in limited MP unfolding and relatively weak hydrophobic interactions in the composite gels, which were less effective in improving the gel properties of the MP gels. This study provides potential strategies for enhancing the gelling properties of low-salt meat products via application of US and KC.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    本研究考察了亚麻籽胶(FG)对聚集体结构的影响,糯米淀粉(WRS)的糊化和流变特性.结果显示有序分子结构(R1047/1024)增加,相对结晶度(RC),紧密度(α),和微相异质性(ε,纳米聚集体的密度,从3.52到4.23)对于WRS-FG复合物。这些建议FG促进了WRS更有组织的分子和晶体结构的发展,伴随着具有较高密度的有序纳米聚集体的形成(即,纳米聚集结构)。此外,添加FG导致形成增强的凝胶网络结构,其特征在于更厚的层壁和更均匀的孔。这些结构转变导致糊化温度升高(To,从56.90°C到62.10°C)和焓(ΔH),以及糊状物粘度的变化(PV,从1285.00mPa·s到1734.00mPa·s),和网络结构的刚度(例如,损耗角正切减小)。这些结果表明,FG可以通过合理控制淀粉的淀粉固有结构来有效调节WRS的技术功能特性。本研究可以改善淀粉的糊化和胶凝性能,从而推动了优质淀粉食品的开发,延长了保质期,特别是糯米粉制品。
    This study examines the effects of flaxseed gum (FG) on the aggregate structure, pasting and rheological properties of waxy rice starch (WRS). Results display an increase in the ordered molecular structure (R1047/1024), relative crystallinity (RC), compactness (α), and microphase heterogeneity (ε, density degree of nanoaggregates, from 3.52 to 4.23) for WRS-FG complexes. These suggested FG facilitated the development of more organized molecular and crystalline structures of WRS, accompanied by the formation of ordered nanoaggregates with higher density (i.e., nano-aggregation structure). Also, FG addition resulted in the formation of enhanced gel network structure characterized by thicker layer walls and more uniform pores. These structural transformations contributed to a rise in gelatinization temperature (To, from 56.90 °C to 62.10 °C) and enthalpy (ΔH), as well as alterations in paste viscosities (PV, from 1285.00 mPa·s to 1734.00 mPa·s), and the rigidity of network structure (e.g., decreased loss tangent). These results indicate that FG could effectively regulate the techno-functional properties of WRS by rationally controlling the starch intrinsic structures of starch. And this study may improve the pasting and gelling properties of starch, thus driving the development of high-quality starchy foods and prolonging their shelf life, especially for glutinous rice flour products.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    丝胶蛋白具有优异的生物相容性,抗氧化,和可加工性。然而,制造大量坚固而坚韧的纯再生丝胶材料仍然是一个重大挑战。在这里,结合自由基链聚合反应和液固相转化方法,设计了一种具有高延展性的轻质丝胶结构膜。所得到的聚丙烯腈接枝丝胶薄膜显示出能够毫不费力地在高强度和高韧性之间切换的能力,最大拉伸强度和杨氏模量值为21.92±1.51MPa和8.14±0.09MPa,分别,断裂伸长率和韧性分别达到344.10±35.40%和10.84±1.02MJ·m-3。我们的发现表明,将丝胶蛋白掺入再生膜中有助于通过影响聚合溶液中分子链的缠结来改变其机械性能。使用红外光谱和X射线衍射进行的结构分析证实,丝胶蛋白通过影响凝聚态构象的转变来调节机械性能。这项工作提出了一种方便而有效的策略,可同时解决丝胶蛋白的回收利用以及生产在生物医学中具有潜在应用的再生蛋白质基薄膜。可穿戴,或食品包装。
    Sericin protein possesses excellent biocompatibility, antioxidation, and processability. Nevertheless, manufacturing large quantities of strong and tough pure regenerated sericin materials remains a significant challenge. Herein, we design a lightweight structural sericin film with high ductility by combining radical chain polymerization reaction and liquid-solid phase inversion method. The resulting polyacrylonitrile grafted sericin films exhibit the ability to switch between high strength and high toughness effortlessly, the maximum tensile strength and Young\'s modulus values are 21.92 ± 1.51 MPa and 8.14 ± 0.09 MPa, respectively, while the elongation at break and toughness reaches up to 344.10 ± 35.40 % and 10.84 ± 1.02 MJ·m-3, respectively. Our findings suggest that incorporating sericin into regenerated films contributes to the transformation of their mechanical properties through influencing the entanglement of molecular chains within polymerized solutions. Structural analyses conducted using infrared spectroscopy and X-ray diffraction confirm that sericin modulates the mechanical properties by affecting the transition of condensed matter conformation. This work presents a convenient yet effective strategy for simultaneously addressing the recycling of sericin as well as producing regenerated protein-based films that hold potential applications in biomedical, wearable, or food packaging.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    伤口愈合的过程需要特定的环境,因此,促使人们对为此目的利用水凝胶进行广泛的研究。虽然已经研究了许多水凝胶结构,发现一种具有良好生物相容性的自修复水凝胶,特殊的机械性能,有效的止血和抗菌性能仍然不常见。在这项工作中,通过简单的反应精心设计了聚乙烯醇(PVA)混合水凝胶,其中CuxO锚定的海泡石被并入水凝胶中。结果表明,海泡石的引入大大提高了韧性,PVA水凝胶的自修复和粘附性能。CuxO纳米粒子赋予水凝胶对金黄色葡萄球菌和大肠杆菌具有优异的抗菌性能。通过大鼠实验在体外和体内验证了混合水凝胶在快速止血和伤口愈合中的应用。因此,这项工作证明了设计可生物降解的止血和伤口愈合材料的有效策略。
    The process of wound healing necessitates a specific environment, thus prompting extensive research into the utilization of hydrogels for this purpose. While numerous hydrogel structures have been investigated, the discovery of a self-healing hydrogel possessing favorable biocompatibility, exceptional mechanical properties, and effective hemostatic and antibacterial performance remains uncommon. In this work, a polyvinyl alcohol (PVA) hybrid hydrogel was meticulously designed through a simple reaction, wherein CuxO anchored sepiolite was incorporated into the hydrogel. The results indicate that introduction of sepiolite greatly improves the toughness, self-healing and adhesion properties of the PVA hydrogels. CuxO nanoparticles endow the hydrogels with excellent antibacterial performance towards Staphylococcus aureus and Escherichia coli. The application of hybrid hydrogels for fast hemostasis and wound healing are verified in vitro and in vivo with rat experiments. This work thereby demonstrates an effective strategy for designing biodegradable hemostatic and wound healing materials.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    为评价复合聚合物改性沥青的热稳定性,热塑性弹性体丁苯橡胶(SBR)/聚丙烯(PP)颗粒使用热熔共混技术制备,以丁基橡胶粉和废聚丙烯颗粒为原料。采用频率扫描试验和多应力蠕变恢复(MSCR)试验,研究了不同评价指标对SBR/PP改性沥青热稳定性的影响,使用Cole-Cole图和微观结构图像研究了SBR/PP颗粒与沥青的相容性。测试表明,首先,加入SBR/PP热塑性弹性体可以提高沥青的性能等级(PG)等级,增强沥青在高低温环境下的适应性,评价分离指标能更合理地反映复合改性沥青的高温储存稳定性。此外,胶塑比越大,复合改性沥青的高温热稳定性越差。此外,在复合颗粒中加入添加剂可以促进SBR/PP颗粒在沥青中更均匀地分散,形成更理想的微观结构,提高复合改性沥青的热稳定性。最终,Cole-Cole图的半圆形曲线可以反映SBR/PP改性沥青两相结构的相容性特征,可作为评价聚合物改性沥青相容性的辅助指标。
    To evaluate the thermal stability of composite polymer-modified asphalt, thermoplastic elastomer styrene-butadiene rubber (SBR)/polypropylene (PP) pellets were prepared using a hot-melt blending technique, with butyl rubber powder and waste polypropylene pellets as raw materials. The effects of different evaluation indexes on the thermal stability of SBR/PP-modified asphalt were investigated using a frequency scan test and a multi-stress creep recovery (MSCR) test, and the compatibility of SBR/PP particles with asphalt was studied using the Cole-Cole diagram and microstructure images. The tests show that, firstly, the performance grade (PG) classification of asphalt can be improved by adding an SBR/PP thermoplastic elastomer to enhance the adaptability of asphalt in high- and low-temperature environments, and the evaluation separation index can reflect the high-temperature storage stability of composite-modified asphalt more reasonably. Additionally, the larger the rubber-to-plastic ratio the worse the high-temperature thermal stability of composite-modified asphalt. Moreover, the addition of additives to the composite particles can promote the SBR/PP particles in the asphalt to be more uniformly dispersed, forming a more desirable microstructure and improving the thermal stability of composite-modified asphalt. Ultimately, the semicircular curve of the Cole-Cole diagram can reflect the compatibility characteristics of the two-phase structure of SBR/PP-modified asphalt, which can be used as an auxiliary index to evaluate the compatibility of polymer-modified asphalt.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    由于半结晶聚酯(乳酸)(PLA)与其他增强材料结合使用,相分离等挑战,环境污染,制造困难可能会阻碍解放军的利益,包括完全的生物降解性和强大的机械性能。在目前的调查中,熔融共混用于建立低分子量和高分子量聚乳酸(LPLA和HPLA)的混合物。结晶度,流变学,使用旋转流变仪对组合物的力学性能进行了分析,差示扫描量热法,X射线衍射,偏振光学显微镜,扫描电子显微镜,和通用测试设备。结果表明LPLA和HPLA之间的相容性。此外,LPLA浓度的增加导致结晶速率的降低,球晶尺寸,分数结晶度,等温结晶过程中的XRD峰强度。LPLA在等温结晶过程中充当稀释剂,而HPLA在非等温结晶过程中充当成核剂,促进LPLA晶体的生长并导致共结晶。具有5%LPLA质量分数的共混体系表现出最高的拉伸强度并增强流变特性。通过有效地利用PLA的各种分子量之间的关系,流变学,和结晶行为,这种审查改善了材料的物理和机械特性,开辟新的机遇。
    As semi-crystalline polyester (lactic acid) (PLA) is combined with other reinforcing materials, challenges such as phase separation, environmental pollution, and manufacturing difficulties could hinder the benefits of PLA, including complete biodegradability and strong mechanical properties. In the present investigation, melt blending is utilized to establish a mixture of low- and high-molecular-weight polylactic acids (LPLA and HPLA). The crystallinity, rheology, and mechanical properties of the combination were analyzed using rotational rheometry, differential scanning calorimetry, X-ray diffraction, polarized optical microscopy, scanning electron microscopy, and universal testing equipment. The results demonstrate compatibility between LPLA and HPLA. Moreover, an increase in LPLA concentration leads to a decrease in the crystallization rate, spherulite size, fractional crystallinity, and XRD peak intensity during isothermal crystallization. LPLA acts as a diluent during isothermal crystallization, whereas HPLA functions as a nucleating agent in the non-isothermal crystallization process, promoting the growth of LPLA crystals and leading to co-crystallization. The blended system with a 5% LPLA mass fraction exhibits the highest tensile strength and enhances rheological characteristics. By effectively leveraging the relationship between various molecular weights of PLA\'s mechanical, rheological, and crystallization behavior, this scrutiny improves the physical and mechanical characteristics of the material, opening up new opportunities.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

       PDF(Pubmed)

  • 文章类型: Journal Article
    污泥处理工艺的数字化改造需要在线感知脱水能力。本课题基于宏观剪切流变学已经尝试了多年。然而,流变行为与脱水性之间的关系仍然不置可否,原因还不清楚。在这里,提出了二元凝胶状结构模型,包括超絮凝水平的相互作用网络和絮凝水平的凝胶状结构。采用包括光学镊子在内的多种先进技术来精确理解二元凝胶状结构,并对这种凝胶状结构之间的相关机制进行分类。流变行为,和脱水能力。对8个污水处理厂污泥的分析表明,超絮凝和絮凝水平的二元凝胶状结构与污泥脱水能力有显着关系(p<0.05)。污泥粘弹性行为的进一步解构表明,超絮凝水平的凝胶状结构主导了污泥的流变行为。此外,对四种典型污泥处理工艺中的二元凝胶状结构的直接描述强调了絮体水平结构在确定可脱水性方面的重要性。总的来说,这项研究表明,剪切流变学可能更喜欢强调超絮凝水平的相互作用网络,但掩盖絮凝水平的结构,尽管后者很重要。该观察结果可以为设计用于脱水的坚固传感器提供一般指导。
    The digital transformation of sludge treatment processes requires online sensing of dewaterability. This topic has been attempted for many years based on macroscopic shear rheology. However, the relationship between rheological behavior and dewaterability remains noncommittal, and the reason is unclear. Herein, a binary gel-like structure model was proposed including the interactions network at the supra-flocs level and the gel-like structure at the flocs level. Multiple advanced techniques including optical tweezers were employed to precisely understand the binary gel-like structure and to classify the correlation mechanism between this gel-like structure, rheological behavior, and dewaterability. The analysis of sludge from eight wastewater treatment plants showed the binary gel-like structures at both supra-flocs and flocs levels have significant relationships with sludge dewaterability (p < 0.05). Further deconstruction of the sludge viscoelastic behavior illustrated that the gel-like structure at the supra-flocs level dominates the rheological behavior of sludge. Moreover, the direct description of the binary gel-like structure in four typical sludge treatment processes highlighted the importance of the flocs level\'s structure in determining the dewaterability. Overall, this study revealed that shear rheology may prefer to stress the interactions network at the supra-flocs level but mask the flocs level\'s structure, although the latter is important. This observation may provide a general guideline for the design of robust sensors for dewaterability.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    在这项工作中,四种不同提取方法的效果,酸(HCl),碱(NaOH),酶(纤维素酶/果胶酶),和缓冲液(pH7.0)对牛磺酸果胶的理化性质和功能进行了系统的研究和比较。缓冲液提取得到低产率(2.8%),因此其应用受到限制。酸处理水解了中性侧链,并给出了高半乳糖醛酸含量为72.6%。相比之下,碱和酶保留了侧链,同时降解了聚半乳糖醛酸主链,创造了鼠李糖半乳糖醛酸-I的显性结构。分支结构,低分子量,高度甲基化(42.3%)有助于界面吸附,乳化能力,酶提取产物的细胞抗氧化活性。对于酸提取的产品,强烈的分子内静电排斥限制了接触界面的形成,以防止乳液聚结。此外,他们没有足够的还原端来清除自由基。尽管采用了高支化尺寸(5.0),低甲基化程度(19.5%)影响碱提取产物的乳化能力。这些结果为具有定制性质的果胶多糖生产提供了有用的信息。
    In this work, the effects of four different extraction methods, acid (HCl), alkali (NaOH), enzymes (cellulase/pectinase), and buffer (pH 7.0) on the physicochemical properties and functionalities of burdock pectin were systematically investigated and compared. Buffer extraction gave a low yield (2.8 %) and is therefore limited in its application. The acid treatment hydrolyzed the neutral sidechains and gave a homogalacturonan content of 72.6 %. By contrast, alkali and enzymes preserved the sidechains while degrading the polygalacturonan backbone, creating a rhamnogalacturonan-I dominant structure. The branched structure, low molecular weight, and high degree of methylation (42.3 %) contributed to the interfacial adsorption, emulsifying capacity, and cellular antioxidant activity of the enzyme-extracted product. For the acid-extracted product, the strong intramolecular electrostatic repulsion restricted the formation of a contact interface to prevent coalescence of the emulsion. In addition, they did not have sufficient reducing ends to scavenge free radicals. Although a high branching size (5.0) was adopted, the low degree of methylation (19.5 %) affected the emulsifying capacity of the alkali-extracted products. These results provide useful information for pectic polysaccharides production with tailored properties.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

  • 文章类型: Journal Article
    本文旨在研究超声(US)处理和κ-角叉菜胶(KC)添加对肌原纤维蛋白(MP)的凝胶特性和流变行为的联合影响。没有美国的治疗,KC的掺入提高了MP凝胶的凝胶强度和保水性(WHC)。通过20分钟US处理,凝胶强度为98.61g,WHC为79.87%,这些性能得到了进一步改善。这主要归因于与疏水相互作用和二硫键相关的变化以及MP凝胶中从α-螺旋到β-折叠的转化。此外,US处理20分钟有效地导致MP-KC混合体系的更均匀的聚合物分布,导致MP-KC混合凝胶的粒径较低,G'和G”值最大。然而,较长的US处理时间(30、40和50分钟)使凝胶强度降低,WHC,MP-KC混合凝胶的储能模量和损耗模量,这主要是由于松散无序的凝胶结构的形成。我们目前的结果表明,将US应用于MP的中间处理时间(20分钟)与KC相结合,为提高热诱导MP凝胶的凝胶质量提供了一种潜在的新策略。
    This work aimed to investigate the combined effect of ultrasound (US) treatment and κ-carrageenan (KC) addition on the gelling properties and rheological behaviors of myofibrillar protein (MP). Without US treatment, the KC incorporation promoted the gel strength and water-holding capacity (WHC) of MP gels. These properties were further improved by 20 min US treatment with gel strength of 98.61 g and WHC of 79.87 %, which was mainly attributed to changes associated with hydrophobic interactions and disulfide bonds and the transformation from α-helix to β-sheet in MP gels. In addition, US treatment for 20 min effectively resulted in a more homogeneous polymer distribution of the MP-KC mixed system, leading to lower particle size and the largest G\' and G″ values of the MP-KC mixed gels. However, longer US treatment times (30, 40 and 50 min) rendered lower gel strength, WHC, storage modulus and loss modulus of MP-KC mixed gels, which was mainly due to the formation of loose and disordered gel structures. Our present results indicated that the application of US to MP for an intermediate treatment time (20 min) combined with KC provides a potential and novel strategy to promote the gel qualities of heat-induced MP gels.
    导出

    更多引用

    收藏

    翻译标题摘要

    我要上传

    求助全文

公众号