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.
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  • 文章类型: Journal Article
    黑色素瘤,主要由太阳紫外线(UV)辐射引起,可以通过使用防晒霜来防止。然而,合成防晒霜的使用引起了环境问题。具有抗氧化光保护特性和对癌细胞的细胞毒性作用的天然化合物有望用于预防和治疗具有较小环境影响的黑素瘤。这项研究的重点是白千层精油(EO)的光保护和抗肿瘤应用。从M.leucadendron叶中加氢蒸馏EO,收率为0.59%。气相色谱-质谱法检测单萜和倍半萜。使用相转化法制备具有(NE-EO)和不具有EO(NE-B)的纳米乳液,表现出良好的稳定性,球形或椭圆形形态,和假塑性轮廓。通过分光光度法评估的光保护活性表明,NE-EO比NE-B和游离EO更有效。通过DPPH和ABTS方法评估的抗氧化活性表明,纯的和纳米乳化的EO主要抑制ABTS自由基,显示IC5040.72和5.30µg/mL,分别。对L-929小鼠成纤维细胞的细胞毒性试验,NGM人类黑素细胞,B16-F10黑色素瘤,和MeWo人黑色素瘤显示EO和NE-EO对黑色素瘤细胞的细胞毒性高于非肿瘤细胞。稳定的NE-EO显示出预防和治疗黑素瘤的潜力。需要进一步的研究才能更好地了解这些活动。
    Melanoma, primarily caused by solar ultraviolet (UV) radiation, can be prevented by the use of sunscreens. However, the use of synthetic sunscreens raises environmental concerns. Natural compounds with antioxidant photoprotective properties and cytotoxic effects against cancer cells can be promising for the prevention and treatment of melanoma with less environmental effect. This study focuses on Melaleuca leucadendron essential oil (EO) for photoprotection and antitumor applications. EO was hydrodistilled from M. leucadendron leaves with a 0.59% yield. Gas chromatography-mass spectrometry detected monoterpenes and sesquiterpenes. Nanoemulsions were prepared with (NE-EO) and without EO (NE-B) using the phase inversion method, showing good stability, spherical or oval morphology, and a pseudoplastic profile. Photoprotective activity assessed spectrophotometrically showed that the NE-EO was more effective than NE-B and free EO. Antioxidant activity evaluated by DPPH and ABTS methods indicated that pure and nanoemulsified EO mainly inhibited the ABTS radical, showing IC50 40.72 and 5.30 µg/mL, respectively. Cytotoxicity tests on L-929 mouse fibroblasts, NGM human melanocyte, B16-F10 melanoma, and MeWo human melanoma revealed that EO and NE-EO were more cytotoxic to melanoma cells than to non-tumor cells. The stable NE-EO demonstrates potential for melanoma prevention and treatment. Further research is required to gain a better understanding of these activities.
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  • 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.
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  • 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.
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  • 文章类型: Journal Article
    心脏纤维化是指细胞外基质在心肌内的异常积累,导致僵硬增加和心脏功能受损。从流变学的角度来看,关于心肌行为的知识仍然缺乏,部分原因是缺乏适当的技术来研究体外心脏组织模型的流变学。3D多细胞心脏球体是强大而通用的平台,用于在体外对健康和纤维化的心脏组织进行建模,并研究其机械性能如何被调节。在这项研究中,通过使用悬滴法将新生大鼠心室心肌细胞和成纤维细胞以一定比例共培养来创建心脏球体。通过基于原子力显微镜的应力松弛测量对整个球体进行了此类模型的流变表征。施加应变后,观察到粘弹性双指数松弛,其特征在于快速弛豫时间(τ1),然后是较慢的弛豫时间(τ2)。特别是,与对照相比,成纤维细胞密度较高的球体在两个弛豫时间上均显示减少,τ1相对于τ2的衰减更明显。发现这种反应与这些球状体内细胞外基质的产生增加是相容的,概括了纤维化病理生理学的主要特征。这些结果证明了心脏组织的流变特性如何作为细胞组成和细胞外基质的函数而变化。确认该系统作为心脏纤维化的体外临床前模型的适用性。
    Cardiac fibrosis refers to the abnormal accumulation of extracellular matrix within the cardiac muscle, leading to increased stiffness and impaired heart function. From a rheological standpoint, knowledge about myocardial behavior is still lacking, partially due to a lack of appropriate techniques to investigate the rheology of in vitro cardiac tissue models. 3D multicellular cardiac spheroids are powerful and versatile platforms for modeling healthy and fibrotic cardiac tissue in vitro and studying how their mechanical properties are modulated. In this study, cardiac spheroids were created by co-culturing neonatal rat ventricular cardiomyocytes and fibroblasts in definite ratios using the hanging-drop method. The rheological characterization of such models was performed by Atomic Force Microscopy-based stress-relaxation measurements on the whole spheroid. After strain application, a viscoelastic bi-exponential relaxation was observed, characterized by a fast relaxation time (τ1) followed by a slower one (τ2). In particular, spheroids with higher fibroblasts density showed reduction for both relaxation times comparing to control, with a more pronounced decrement of τ1 with respect to τ2. Such response was found compatible with the increased production of extracellular matrix within these spheroids, which recapitulates the main feature of the fibrosis pathophysiology. These results demonstrate how the rheological characteristics of cardiac tissue vary as a function of cellular composition and extracellular matrix, confirming the suitability of such system as an in vitro preclinical model of cardiac fibrosis.
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  • 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.
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  • 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.
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  • 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.
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  • 文章类型: Journal Article
    全球食品市场的多样性正在扩大,每年都有数千种新产品进入市场,其中营养和功能食品占据重要地位。本研究工作针对三种药材的营养评价,即,姜黄(姜黄L.),姜(生姜),和黑孜然(Nigellasativa)。面包制剂富含这些草药的单独/组合补充剂(1-3%)。稍后,对面包进行了营养分析,流变学,纹理,和感官特征。结果表明,这些草药改善了面包的营养成分,尤其是灰分和纤维,作为最大灰分和纤维含量被注意到在T15(2.0%干燥粉末的每个植物)的值1.64±0.04%和4.63±0.16%,分别。有关流变行为的结果表明,流变特性的变化很小,并且面团发育时间从T0的2.80±0.13分钟略微增加到T10的4.50±0.20分钟。感官属性还表明其明显的适用性,因为添加草药对外部和内部特征的影响最小。虽然一些参数,如地壳和面包屑的颜色受到了黑孜然添加的影响,分别为6.25±0.52和4.44±0.19,在T15中,添加生姜会影响香气特征,以低剂量补充草药的组合减轻了其他草药的不利影响。此外,延长保质期,特别是加入姜黄粉,是这项研究的标志.这项研究得出结论,可以将草药掺入烘焙产品中,以改善功能性草药面包的营养和感官属性。
    The diversity in the global food market is expanding as thousands of new products enter the business every year, among which nutraceutical and functional foods hold important positions. The present research work aimed at the nutritional evaluation of three medicinal herbs, i.e., turmeric (Curcuma longa L.), ginger (Zingiber officinale), and black cumin (Nigella sativa). A bread formulation was enriched with the individual/combined supplementation (1-3%) of these herbs. Later, the bread was analyzed for nutritional, rheological, textural, and sensorial characteristics. The results revealed that the herbs improved the nutritional composition of bread, especially ash and fiber, as the maximum ash and fiber contents were noticed in T15 (2.0% dried powder of each plant) with values of 1.64 ± 0.04% and 4.63 ± 0.16%, respectively. The results regarding the rheological behavior showed minor variations in the rheological traits and a slight increase in dough development time up to 4.50 ± 0.20 min in T10 from 2.80 ± 0.13 min in T0. The sensorial attributes also indicated their marked suitability as external and internal characteristics were least affected by the addition of the herbs. Although some parameters like the crust and crumb colors were affected by the addition of black cumin, showing values of 6.25 ± 0.52 and 4.44 ± 0.19, respectively, in T15, and aroma characteristics were affected by the addition of ginger, supplementation with a combination of herbs at lower doses mitigated the adverse effects of other herbs. Moreover, shelf-life extension, especially with the addition of turmeric powder, was the hallmark of this research. This study concluded that medicinal herbs can be incorporated into baked products to improve the nutritional and sensorial attributes of functional herbal bread.
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  • 文章类型: Journal Article
    本研究旨在使用折射窗干燥(RWD)系统生产干燥的tarhana。干燥过程也在真空下进行;目前的研究是文献中的第一个。使用不同的加热介质,最高温度可以调整到高于RWD研究中使用的水平。考虑到结果,与对照组(烘箱和热风干燥机)相比,RWD的工艺时间节省超过85%和75%,分别。在RWD中干燥的Tarhana样品在真空条件下也比在大气条件下更快(50%)。在大气条件下通过RWD在110°C干燥的样品中,总酚含量(TPC)和总抗氧化活性(TAA)的最高保存率。技术物理性能优于对照组。tarhana汤的流变行为类似于假塑性流动行为,并由幂律和Herschel-Bulkey模型明确定义。总之,RWD可以是tarhana生产的有前途的技术。
    This study aimed to produce dried tarhana using a refractance window drying (RWD) system. The drying process was also carried out under vacuum; the current study is the first in the literature. Using different heating mediums, the maximum temperature can be adjusted to a level above that used in RWD studies. Considering results, process time savings in RWD were over 85% and 75% compared to control groups (oven and hot air dryer), respectively. Tarhana samples dried in RWD were also faster (50%) under vacuum conditions than atmospheric ones. The highest preservation of total phenolic content (TPC) and total antioxidant activity (TAA) was for samples dried by RWD at 110°C under atmospheric conditions. Techno-physical properties were better than the control group. The rheological behavior of tarhana soups was similar to pseudoplastic flow behavior and well defined by the Power law and Herschel-Bulkey models. In conclusion, RWD can be a promising technique for tarhana production.
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