Chemical Engineering and Processing - Process Intensification最新文献_第6页

Stress-blended eddy simulation of flow characteristics in stirred tanks with different curved blade impellers 采用不同曲面叶片叶轮的搅拌槽中流动特性的应力混合涡流模拟

IF 3.8 3区工程技术 Q3 ENERGY & FUELS

Chemical Engineering and Processing - Process Intensification

Pub Date : 2024-10-02 DOI: 10.1016/j.cep.2024.110015

Zhuotai Jia , Mengyao Zhang , Shaoping Ma , Shuang Wu , Mingzhou Yu , Qinghua Zhang , Chao Yang

A high-performance impeller is crucial for enhancing material mixing in a stirred tank. In this work, the flow characteristics created by different curved blade impellers including staggered fan-shaped parabolic disc turbine (SFPDT), swept-back parabolic disc turbine (SPDT), asymmetric staggered parabolic disc turbine (ASPDT) and traditional parabolic disc turbine (PDT) in stirred tanks are investigated numerically by using the stress-blended eddy simulation (SBES) model with a sliding mesh approach. After successful validation of prediction accuracy, power characteristics, mean flow, turbulence characteristics, turbulent kinetic energy (TKE) transport, and trailing vortices behaviors of SFPDT, ASPDT, SPDT and PDT in stirred tanks are systematically evaluated. The results show that ASPDT leads to a significant asymmetric distribution in the axial direction for velocity, TKE and trailing vortices, but the radial jet reduces more severely in the radial direction. The fan-shaped geometry constrains the influence of asymmetric staggered structure on the TKE and trailing vortices distribution for SFPDT. The swept-back blade structure of SPDT results in the lowest power number and TKE values level. These results provide a foundation for the further development and application of high-efficiency impellers.

高性能叶轮对于加强搅拌槽中的物料混合至关重要。本研究采用应力混合涡流模拟（SBES）模型和滑动网格方法，对搅拌槽中不同曲面叶片叶轮（包括交错扇形抛物面圆盘涡轮（SFPDT）、后掠抛物面圆盘涡轮（SPDT）、非对称交错抛物面圆盘涡轮（ASPDT）和传统抛物面圆盘涡轮（PDT））产生的流动特性进行了数值研究。在成功验证预测精度后，系统地评估了 SFPDT、ASPDT、SPDT 和 PDT 在搅拌槽中的功率特性、平均流、湍流特性、湍流动能（TKE）传输和尾涡行为。结果表明，ASPDT 会导致速度、TKE 和尾涡在轴向出现明显的不对称分布，但径向射流在径向的减少更为严重。扇形几何形状限制了不对称交错结构对 SFPDT 的 TKE 和尾涡分布的影响。SPDT 的后掠叶片结构导致了最低的功率数和 TKE 值水平。这些结果为进一步开发和应用高效叶轮奠定了基础。

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引用次数: 0

Performance analysis of photocatalytic reactor with immobilized catalyst for emerging pollutants water treatment using cfd simulation and optimization method 利用 cfd 模拟和优化方法对固定催化剂光催化反应器处理新污染物水的性能分析

IF 3.8 3区工程技术 Q3 ENERGY & FUELS

Chemical Engineering and Processing - Process Intensification

Pub Date : 2024-10-01 DOI: 10.1016/j.cep.2024.110016

Evandro Balestrin , Rita de Cássia Siqueira Curto Valle , Selene Maria Arruda Guelli Ulson de Souza , José Alexandre Borges Valle , Adriano da Silva

An annular labyrinth photocatalytic reactor design was optimized to degrade water emerging pollutants by combining CFD modeling and a Box-Benken experimental design with the desirability function method for the optimization. The optimization was performed by minimizing the pollutant degradation time and the reactor operational cost, varying three factors in the experimental design, the fins number in the labyrinth, the thickness of the annular region, and the solution transmittance. The range of variation levels was 5 to 9, 5 mm to 25 mm, and 35 % to 95 % respectively. The intrinsic kinetic model of the salicylic acid degradation used in CFD simulations takes into account the variations of pollutant concentration and light intensity. Results showed that the transmittance was the most significant factor in minimizing both degradation time and energy cost, followed by the annular reactor thickness and the fins number. The desirability method showed that the combination of the optimized reactor levels was 9 fins, thickness of 25 mm, and transmittance of 95 %. To verify the efficiency gain of the optimized reactor, it was compared the degradation time and the energy cost of the optimized reactor with a conventional annular reactor. The efficiency gain was about 53 %.

通过将 CFD 建模和箱-本肯实验设计相结合，并采用可取函数法进行优化，对环形迷宫光催化反应器的设计进行了优化，以降解水中新出现的污染物。通过改变实验设计中的三个因素，即迷宫中的鳍片数量、环形区域的厚度和溶液透过率，使污染物降解时间和反应器运行成本最小化，从而进行了优化。变化范围分别为 5 至 9、5 毫米至 25 毫米以及 35% 至 95%。CFD 模拟中使用的水杨酸降解内在动力学模型考虑了污染物浓度和光照强度的变化。结果表明，透光率是使降解时间和能源成本最小化的最重要因素，其次是环形反应器厚度和翅片数量。可取性方法显示，优化反应器水平的组合为 9 个鳍片、25 毫米厚度和 95% 的透射率。为了验证优化反应器的增效效果，比较了优化反应器与传统环形反应器的降解时间和能源成本。效率提高了约 53%。

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引用次数: 0

Swelling suppression mechanism on the weathered crust elution-deposited rare earth ores leaching process with cetyltrimethylammonium bromide 十六烷基三甲基溴化铵对风化壳洗脱沉积稀土矿浸出过程的膨胀抑制机制

IF 3.8 3区工程技术 Q3 ENERGY & FUELS

Chemical Engineering and Processing - Process Intensification

Pub Date : 2024-09-30 DOI: 10.1016/j.cep.2024.110014

Qu-tian Zhang , Kai-min Zhang , Fang Zhou , Jian Feng , Xiao-yan Wu , Yi-xin Zhang , Li-sen Zhang , Jun-xia Yu , Ru-an Chi

Weathered crust elution-deposited rare earth ore (WREOs), a national strategic resource, is usually in-situ leached by (NH₄)₂SO₄ solutions to recover the rare earth in industry. However, a large number of (NH₄)₂SO₄ solutions are required in the leaching process to ensure the high recovery efficiency of rare earth, which will cause the hydration swelling of WREOs, leading to the occurrence of landslides. To ensure the mine safety, it is necessary to inhibit the swelling efficiency of WREOs in the leaching process. In this study, the swelling performance of WREOs leached by (NH₄)₂SO₄ was investigated. The effects of the presence of concentrations and leaching temperatures on inhibition of WREOs swelling and further the suppression mechanism was investigated. The results showed that the swelling efficiency of WREOs in 0.1 mol/L (NH₄)₂SO₄ was 0.884 %. With the addition of 0.04 % cetyltrimethylammonium bromide (CTAB), the swelling efficiency was reduced to 0.265 %. The lower temperature effectively inhibits the swelling efficiency of WREOs, while the pH of the leaching solution showed little to no effect. Zeta potential results showed that a small amount of cationic surfactant could balance the surface charge of WREOs, thus inhibiting its swelling efficiency. XRD and SEM results revealed that the swelling in WREOs was mainly due to surface hydration. This study can assist to solve the shortcomings of low leaching rate and lower the risk of the landslides in the mining process.

风化壳洗脱沉积稀土矿（WREOs）是国家战略资源，工业上通常采用（NH4）2SO4 溶液原位浸出法回收稀土。然而，为了保证稀土的高回收效率，浸出过程中需要大量的（NH4）2SO4 溶液，这将造成稀土矿的水化膨胀，导致塌方的发生。为确保矿山安全，有必要在浸出过程中抑制 WREOs 的膨胀效率。本研究调查了(NH4)2SO4浸出的钨资源氧化物的溶胀性能。研究了浓度和浸出温度的存在对抑制 WREOs 溶胀的影响，并进一步探讨了抑制机制。结果表明，在 0.1 mol/L (NH4)2SO4 中，禾草属植物的溶胀效率为 0.884 %。加入 0.04 % 的十六烷基三甲基溴化铵（CTAB）后，溶胀效率降至 0.265 %。较低的温度有效抑制了 WREOs 的溶胀效率，而浸出液的 pH 值几乎没有影响。Zeta 电位结果表明，少量阳离子表面活性剂可平衡 WREOs 的表面电荷，从而抑制其溶胀效率。XRD 和 SEM 结果表明，WREOs 的溶胀主要是由表面水合作用引起的。这项研究有助于解决浸出率低的缺点，降低采矿过程中的滑坡风险。

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引用次数: 0

Ethanol removal by stripping with CO2 reduced-size bubbles: Mechanical and thermodynamic entrainments 利用减小尺寸的二氧化碳气泡进行汽提去除乙醇：机械和热力学夹带

IF 3.8 3区工程技术 Q3 ENERGY & FUELS

Chemical Engineering and Processing - Process Intensification

Pub Date : 2024-09-29 DOI: 10.1016/j.cep.2024.110011

Rauber D. Pereira , Letícia P. Almeida , Marina D.B. Sousa , Mariane M. Buffo , Ivan I.K. Veloso , Kaio C.R. Silva , Antonio J.G. Cruz , Alberto C. Badino

The efficiency of stripping processes for volatile compounds is governed by mechanical and thermodynamic entrainments, which play crucial roles in ethanol removal during the extractive fermentation process. These mechanisms depend on variables such as bubble diameter, ethanol concentration, liquid volume, pressure, and temperature. However, the quantification of each of them separately and their dependence on bubble diameter have never been addressed. The present study proposes a new methodology to evaluate both mechanical and thermodynamic entrainments, based on experimental data and thermodynamic equilibrium analysis of the bubbles in reactors with working volumes of 10.0 and 50 L, aiming to clarify the role that bubble diameter (microbubbles, fine and coarse bubbles) plays in these mechanisms. The results indicated that thermodynamic equilibrium was reached for any size of bubbles up to 5 mm in diameter, under a wide range of experimental conditions with specific gas flow rates from 0.22 to 10 vvm. Equally important, mechanical entrainment was found to enrich the gas phase in ethanol by a factor of 15, representing a higher concentration factor than for thermodynamic entrainment, which was inconceivable initially. This introduces a new and promising approach to intensify the stripping process of volatile compounds by means of mechanical entrainment.

在萃取发酵过程中，机械和热力学夹带对乙醇的去除起着至关重要的作用。这些机制取决于气泡直径、乙醇浓度、液体体积、压力和温度等变量。然而，如何分别量化它们以及它们与气泡直径的关系还从未得到过研究。本研究根据工作容积为 10.0 升和 50 升的反应器中气泡的实验数据和热力学平衡分析，提出了一种评估机械夹带和热力学夹带的新方法，旨在阐明气泡直径（微泡、细泡和粗泡）在这些机制中的作用。结果表明，在特定气体流速为 0.22 至 10 vvm 的各种实验条件下，直径不超过 5 毫米的任何大小的气泡都能达到热力学平衡。同样重要的是，研究发现机械夹带可使乙醇中的气相富集 15 倍，比热力学夹带的浓度系数更高，这在最初是不可想象的。这为通过机械夹带强化挥发性化合物的汽提过程提供了一种新的可行方法。

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引用次数: 0

Enhanced mixing characteristics of unbaffled U-shaped microreactor coupled oscillatory flow 增强无挡板 U 型微反应器耦合振荡流的混合特性

IF 3.8 3区工程技术 Q3 ENERGY & FUELS

Chemical Engineering and Processing - Process Intensification

Pub Date : 2024-09-29 DOI: 10.1016/j.cep.2024.110009

Liping Yu , Meiqin Zheng , Jiawei Wang , Zuoyi Yan , Wei Yao , Haohong Li , Huidong Zheng , Jingjing Chen

The Microscale Oscillatory Flow Reactor (MOFR) can achieve good plug flow and micromixing performance simultaneously at laminar net flow conditions. An unbaffled U-shaped microreactor coupled with oscillating flow technology was designed to study the macro and micromixing performance. Firstly, the influence of oscillations on the flow performance was studied to reveal the formation rule of vortex. The simulation results showed that the continuous formation and destruction of periodic vortexes occurred in the microreactor with oscillation. With the increase of oscillation intensity, the vortex size in the radial direction first gradually increased and then becomes stable, and gradually moved axially, resulting in axial diffusion. Secondly, the effect of oscillation on the macromixing and micromixing performance were investigated. The results showed that the coupling oscillation could greatly improve the macromixing and micromixing performance. The macromixing and micromixing performance were promoted simultaneously at lower oscillation intensity and then tended to be flat due to the axial diffusion at high oscillation intensity. When φ>6.05, the minimum micromixing time and the maximum number of tanks can be achieved at the same time. At a velocity ratio of about 23, FoM reached a maximum of about 3.5.

微尺度振荡流反应器（MOFR）可在层流净流条件下同时实现良好的塞流和微混合性能。为了研究宏观和微观混合性能，我们设计了一个无褶皱的 U 型微反应器，并采用了振荡流技术。首先，研究了振荡对流动性能的影响，揭示了漩涡的形成规律。模拟结果表明，周期性漩涡在带振荡的微反应器中不断形成和破坏。随着振荡强度的增加，漩涡在径向的尺寸先逐渐增大，然后趋于稳定，并逐渐向轴向移动，形成轴向扩散。其次，研究了振荡对大混合和微混合性能的影响。结果表明，耦合振荡可大大改善大混合和微混合性能。在较低的振荡强度下，大混合和微混合性能同时得到提升，而在较高的振荡强度下，由于轴向扩散，大混合和微混合性能趋于平缓。当φ>6.05时，可以同时达到最短的微混合时间和最多的槽数。当速度比约为 23 时，FoM 达到最大值约 3.5。

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引用次数: 0

Investigation on the effect of vertical baffle plate on droplet size distribution and mixing efficiency in Taylor Reactor 研究垂直挡板对泰勒反应器中液滴粒度分布和混合效率的影响

IF 3.8 3区工程技术 Q3 ENERGY & FUELS

Chemical Engineering and Processing - Process Intensification

Pub Date : 2024-09-28 DOI: 10.1016/j.cep.2024.110010

Xiao Dong, Shijie Yan, Xiaoyong Yang, Ningpu Liu, Shilong Du, Bingjie Wang, Fuwei Lv, Zhishan Bai

The Taylor reactor is a dynamic mixer based on the principles of Taylor vortex flow. However, traditional Taylor reactors feature smooth inner and outer cylinder surfaces, presenting challenges in achieving uniform mixing and efficient mass transfer. These limitations do not meet the requirements of modern chemical processes for highly efficient mixing equipment. This article introduces a novel Taylor reactor equipped with vertical baffle plates, designed to overcome these challenges. A comprehensive methodology combining CFD-PBM and experimental techniques was employed to investigate both droplet size distribution and mixing performance in the annular gap. Compared to traditional designs, the new device demonstrates significantly lower COV at 0.018 and Sauter mean diameter at 38.3 μm. Optimal mixing efficiency is achieved at rotating Reynolds number (Re) of 1.17 × 10⁵ and inlet Reynolds number (Re_i) of 2.65 × 10³. Numerical simulation results suggest that vertical baffles effectively enhance liquid-liquid interactions including collision, interface contact, and droplet residence time within the annular gap. Moreover, increased turbulent stress in the flow field contributes to greater vorticity, turbulence intensity, and turbulent kinetic energy resulting in smaller droplet sizes and improved mixing efficiency. These findings provide a theoretical foundation for hydraulic structural optimization design as well as widespread application of Taylor reactors.

泰勒反应器是一种基于泰勒涡流原理的动态混合器。然而，传统的泰勒反应器具有光滑的内外圆筒表面，这给实现均匀混合和高效传质带来了挑战。这些局限性无法满足现代化学工艺对高效混合设备的要求。本文介绍了一种配备垂直挡板的新型泰勒反应器，旨在克服这些挑战。采用了一种结合 CFD-PBM 和实验技术的综合方法来研究环形间隙中的液滴粒度分布和混合性能。与传统设计相比，新装置的 COV 值（0.018）和 Sauter 平均直径（38.3 μm）明显降低。在旋转雷诺数（Re）为 1.17 × 105 和入口雷诺数（Rei）为 2.65 × 103 时，可达到最佳混合效率。数值模拟结果表明，垂直挡板有效地增强了环形间隙内的液-液相互作用，包括碰撞、界面接触和液滴停留时间。此外，流场中湍流应力的增加有助于提高涡度、湍流强度和湍流动能，从而减小液滴尺寸并提高混合效率。这些发现为水力结构优化设计以及泰勒反应器的广泛应用提供了理论基础。

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引用次数: 0

Interdisciplinary approaches in process intensification: Building the next generation of engineers 工艺强化的跨学科方法：培养下一代工程师

IF 3.8 3区工程技术 Q3 ENERGY & FUELS

Chemical Engineering and Processing - Process Intensification

Pub Date : 2024-09-28 DOI: 10.1016/j.cep.2024.110007

Ines Esma Achouri

引用次数: 0

H2-rich gas production from gasification of oily sludge via supercritical water technology: Synergy effect of KOH, K2CO3, and reaction parameters 通过超临界水技术气化含油污泥产生富含 H2- 的气体：KOH、K2CO3 和反应参数的协同效应

IF 3.8 3区工程技术 Q3 ENERGY & FUELS

Chemical Engineering and Processing - Process Intensification

Pub Date : 2024-09-27 DOI: 10.1016/j.cep.2024.110008

Jie Cheng , Seyyed Abbas Nouri Gehraz , Saadi Khodamoradi , Dunya Jani Qali , Dheyaa J. Jasim

Yielding H₂ as a sustainable gaseous fuel from oily sludge is of critical importance in mitigating the environmental effects linked with the usage of conventional fossil fuels. The deficiency in the drying of biomass has ensued to the exploration of supercritical water gasification (SCWG) as an effective method for harvesting H₂-rich gas. This study utilized a combination of two alkali catalysts (KOH and K₂CO₃) in supercritical water to generate a H₂-rich gas from a conventional oily sludge. The Box-Behnken design was utilized to assess the impact of different operational variables, including temperature (400–600 °C), feed concentration (FC) (between 5 and 25 wt.%), residence time (RT) (15–45 min), and catalyst to feed mass ratios (FMR) (0–0.50). The maximum production of H₂ at 3.22 mmolg-feed^-1 was achieved under optimal conditions of 600 °C, 32.76 min, and a KOH to FMR of 0.45 and K₂CO₃ to FMR of 0.28.

从含油污泥中提取 H2 作为可持续的气体燃料，对于减轻使用传统化石燃料对环境造成的影响至关重要。由于生物质干燥过程中存在的不足，人们开始探索超临界水气化（SCWG）这一获取富含 H2 气体的有效方法。本研究利用超临界水中两种碱催化剂（KOH 和 K2CO3）的组合，从传统的含油污泥中产生富含 H2- 的气体。采用盒式贝肯设计评估了不同操作变量的影响，包括温度（400-600 °C）、进料浓度（FC）（5-25 wt.%）、停留时间（RT）（15-45 分钟）和催化剂与进料的质量比（FMR）（0-0.50）。在 600 °C、32.76 分钟、KOH 与 FMR 之比为 0.45 和 K2CO3 与 FMR 之比为 0.28 的最佳条件下，H2 的最大产量为 3.22 mmolg-feed-1。

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引用次数: 0

Improvement of mixing efficiency in twisted micromixers: The impact of cross-sectional shape and eccentricity ratio 提高扭曲微搅拌器的搅拌效率：横截面形状和偏心率的影响

IF 3.8 3区工程技术 Q3 ENERGY & FUELS

Chemical Engineering and Processing - Process Intensification

Pub Date : 2024-09-25 DOI: 10.1016/j.cep.2024.110006

Haniyeh Yousefi , Shima Akar , Hamid Niazmand , Seyed Ali Mousavi Shaegh

Microfluidic mixers with twisted geometries show promise for high mixing efficiency, especially at elevated flow rates. However, there is a lack of understanding regarding the optimal geometrical parameters to enhance mixing across various Reynolds numbers. This study aimed to explore the influence of pitch number, cross-section geometry, and eccentricity ratio on the performance of the twisted micromixer. The flow field in these micromixers was solved numerically and the mixing index and pressure drop were calculated for Reynolds numbers of 1 to 400. Twisted micromixers with rectangular cross-sections and aspect ratios of 0.5 and 2 outperformed those with square cross-sections by up to 34% in mixing efficiency, exceeding 90% efficiency for Reynolds numbers from 1 to 400. Moreover, the eccentricity ratio (ER) was studied for the first time in twisted micromixers in this study and demonstrated a critical role in improving the mixing performance. For low to intermediate Reynolds numbers, the highest ER of 0.75 showed the best performance, while for high Reynolds numbers, an ER of 0.5 was optimal. These insights offer valuable direction for designing high-performance micromixers for advanced microfluidic systems.

具有扭曲几何形状的微流体混合器有望实现较高的混合效率，尤其是在流速较高的情况下。然而，人们对在不同雷诺数条件下增强混合效果的最佳几何参数还缺乏了解。本研究旨在探索螺距数、横截面几何形状和偏心率对扭曲微混器性能的影响。对这些微搅拌器中的流场进行了数值求解，并计算了雷诺数为 1 到 400 时的混合指数和压降。横截面为矩形、纵横比为 0.5 和 2 的扭曲微搅拌器的混合效率比横截面为正方形的微搅拌器高出 34%，在雷诺数为 1 到 400 的情况下，混合效率超过 90%。此外，本研究首次对扭曲微搅拌器的偏心比（ER）进行了研究，结果表明偏心比在提高搅拌性能方面起着至关重要的作用。对于中低雷诺数，0.75 的最高 ER 显示出最佳性能，而对于高雷诺数，0.5 的 ER 则是最佳选择。这些见解为设计用于先进微流控系统的高性能微搅拌器提供了宝贵的方向。

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引用次数: 0

Bioactive compound extraction from mandarin peel via cloud point extraction and enhanced shelf stability through sodium alginate encapsulation 通过浊点萃取从柑橘皮中提取生物活性化合物，并通过海藻酸钠封装提高货架稳定性

IF 3.8 3区工程技术 Q3 ENERGY & FUELS

Chemical Engineering and Processing - Process Intensification

Pub Date : 2024-09-24 DOI: 10.1016/j.cep.2024.110000

Arpit N. Patel, Pavankumar R. More, Shalini S. Arya

The mandarin peel is a valuable natural source of phenolic compounds known for their high antioxidant properties. Cloud point extraction (CPE) emerges as a groundbreaking technique for harvesting bioactives compounds. The optimal CPE conditions were 8.5 % (v/v) Triton X-114 at 30 °C with pH 4, and 7 % (w/v) salt concentration. At optimal CPE, 93.75 % phenolic compounds and 88.35 % flavonoids were recovered their respective yields of 16.85 mg gallic acid equivalent per gram and 2.45 mg quercetin equivalent per gram of mandarin peel. The micellar mandarin peel extract (MMPE) exhibited 47.05 % antioxidant activity. Further, MMPE was encapsulated in sodium alginate beads to improve its stability. The highest 74.05 % encapsulation efficiency was achieved using 2.5 % sodium alginate. The MMPE beads showed increased hardness due to rigid shell. Structural characterizations also explained more uniform and densely packed internal structure of MMPE beads compared to blank beads. Functional properties and thermal stability assessments showcased superior properties in MMPE beads. Release kinetics studies revealed that 60–70 % of polyphenols were liberated within 30 min under both aqueous and simulated gastric environments. CPE presents a promising avenue for converting mandarin peel waste into valuable bioactives with antioxidant properties.

柑橘皮是一种宝贵的天然酚类化合物来源，具有很高的抗氧化性。云点萃取（CPE）是获取生物活性化合物的突破性技术。CPE 的最佳条件为 8.5 %（v/v）的 Triton X-114，温度为 30 °C，pH 值为 4，盐浓度为 7 %（w/v）。在最佳 CPE 条件下，酚类化合物的回收率为 93.75%，黄酮类化合物的回收率为 88.35%，每克柑橘皮的产量分别为 16.85 毫克没食子酸当量和 2.45 毫克槲皮素当量。胶束柑皮提取物（MMPE）显示出 47.05% 的抗氧化活性。此外，为了提高稳定性，还将 MMPE 封装在海藻酸钠珠中。海藻酸钠含量为 2.5%，封装效率最高，达到 74.05%。由于外壳坚硬，MMPE 珠的硬度有所提高。结构表征还表明，与空白珠子相比，MMPE 珠子的内部结构更加均匀和致密。功能特性和热稳定性评估显示了 MMPE 珠的优异特性。释放动力学研究表明，在水环境和模拟胃环境下，60-70% 的多酚在 30 分钟内释放。CPE 为将柑皮废弃物转化为具有抗氧化特性的宝贵生物活性物质提供了一条前景广阔的途径。

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引用次数: 0