亚临界水萃取技术及其在有效成分提取和分析领域中的应用

综述了亚临界水萃取技术在有效成分提取和分析领域的研究现状,主要介绍了亚临界水萃取技术在挥发油、黄酮、多糖和蛋白质等天然植物有效成分提取及分析检测等领域的应用,并概述了超声波、微波、酶法等技术与亚临界水萃取联用,最后展望了亚临界水萃取技术的未来发展方向,为该技术的推广及实际应用提供参考。     

柿叶挥发油的提取及抗菌活性的研究进展

柿叶具有较高的营养价值和医疗保健作用,能制作保健茶、抗菌药物、食品香料等应用;通过水蒸气蒸馏、有机溶剂提取、超临界CO2萃取等方法对柿叶挥发油提取研究作了较为详细的综述,展望酶解辅助提取、亚临界水萃取等现代植物有效成分提取方法在柿叶有效成分提取研究;综述了柿叶提取物的抗菌作用及抗菌成分分析,表明柿叶提取物对金黄色葡萄球菌、枯草芽孢杆菌等细菌具有不同程度的拮抗作用。     

中草药挥发油提取新技术——亚临界水萃取

介绍一种中药挥发油提取的新技术,对亚临界水在中药挥发油提取方面的应用进行综述。探讨亚临界水在中药挥发油萃取过程中萃取温度、萃取压力、萃取时间、夹带剂等因素对萃取效果的影响,并将其与传统的水蒸气蒸馏、索氏提取及目前流行的超临界二氧化碳流体萃取进行对比。结果表明,使用亚临界水提取技术不仅挥发油收率高,提取时间更为迅速,是一种新型而更贴近传统的中药提取方式。     

亚临界水萃取技术在天然产物提取中的研究进展

较详细地介绍了亚临界水萃取技术的原理、设备、工艺流程、影响萃取效果的因素、在天然产物领域的应用及研究成果.指出了该技术存在的问题,并对其应用与发展前景进行了探讨.     

亚临界水提取技术在物质提取方面的应用

亚临界水提取技术(SCWE),是一种以亚临界水(SCW)为提取溶剂的新型提取技术,具有高效、绿色等优势。本文在简要介绍亚临界水的基础上,综述了其在生物活性物质提取,环境、食品中有害成分提取检测等方面的研究进展,并概述了提取过程的影响因素,以及与多种辅助强化技术联用的研究结果。最后展望了其未来可能的发展方向,为该技术的进一步发展及实际应用提供参考。     

植物活性成分提取新技术及最新研究进展

详细介绍了超声波提取、微波辅助提取、超临界流体提取、亚临界水提取等几种近年来植物活性成分提取方面的新技术,及超声强化超临界CO2提取技术、超声-微波协同提取技术、超声强化亚临界水提取等最新研究进展,重点阐述了这些新技术的原理、应用现状,指出了存在的问题,最后对这些新技术的应用及发展前景进行了探讨.     

植物精油提取技术研究进展

精油提取技术对精油品质以及植物原料的综合利用都具有重要的影响。本文综述了从实验室到工业化精油生产中常用的8类提取技术及其最新研究进展:共水蒸馏,水蒸气蒸馏,同时蒸馏萃取,压榨法,超临界流体萃取,亚临界水萃取,无溶剂微波萃取和即时控制降压提取法,并指出了这些提取技术的优缺点及精油提取产业的一些发展趋势。     

CO2超临界萃取技术提取中药有效成分

本文较系统地介绍了CO2超临界萃取技术提取中药有效成分的优点,重点讲述了已工业化的几项提取过程,突出了该技术提取中药水溶性有效成分的应用前景。     

超声强化亚临界水萃取装置设计及声空化分析

为了充分利用亚临界水萃取技术和超声强化技术的优点,设计了超声强化亚临界水萃取的装置,并根据声空化阈值的基本理论和亚临界水的物态数值,研究了超声空化阈值随业临界水的压力和温度的变化规律.结果表明:该装置可方便实现静态萃取和动态循环萃取;超声阈值随亚临界水中压力的增大而增大,而随亚临界水温度的升高而降低;在理想纯状态下亚临界水的空化阈值比常温水的空化阈值要低.当存在空化泡的情况下,亚临界水的空化阈值比常温水的空化阈值要高.     

亚临界水萃取紫草中左旋／右旋紫草素的工艺优化

研究了亚临界水萃取技术富集紫草中左旋/右旋紫草素的工艺过程,采用响应曲面法对影响紫草素提取率的工艺参数进行分析优化.考察了萃取温度、萃取时间和固液比对紫草素提取率的影响,结果发现三个因素在各自考察的实验范围内均有显著影响.采用可见分光光度法对亚临界水提取液中紫草素的浓度进行分析,在510 nm波长下测得的标准线性方程为y=24.77x+0.0311,相关系数为0.9905,紫草素浓度的线性范围是0.0084～0.0540 mg·mL-1.响应曲面分析模型预测的最佳提取条件是:固液比为7.875 g·L-1,在20 MPa、117.5℃下提取18 min,此时紫草素最大提取率是2.02 mg·g-1,与模型预测值基本相符.采用亚临界水萃取紫草素具有高效、环保、操作简便等优势,利用响应曲面设计能够有效地优化萃取过程,为该技术的推广提供了一定的理论支持.     

Using membrane-supported liquid-liquid extraction for the measurement of extraction kinetics

Membrane-supported liquid-liquid extraction uses artificial membranes for the generation of a phase interface between the two liquid phases involved in extraction. Additional equipment for the generation of droplets as well as phase separation afterwards is no longer necessary. Since the membranes used for this special type of extraction are quite well described concerning thickness, porosity, tortuosity and material it is possible to generate information about the diffusion coefficient of the component to be extracted within the preferred solvent from extraction trails easily. This article describes an experimental set-up for both the proof of principle of membrane-supported liquid-liquid extraction and, using a dedicated computer-aided data treatment, how to calculate the overall mass transfer coefficient as well as the diffusion coefficient for a given system within moderate testing duration.     

加压溶剂法提取雷公藤甲素及其条件优化

以雷公藤为原料,采用加压溶剂法提取雷公藤甲素,以1,2-二氯乙烷为溶剂,考察了提取时间、料液比和提取温度等因素对提取工艺的影响,并在单因素试验基础上,根据中心组合试验设计原理采用三因素三水平的响应面分析法进行工艺优化,得到提取过程优化的工艺条件为:料液比1:9.7,提取温度115℃,提取时间80min,雷公藤甲素的实际得率可达0.173‰,纯度为1.21%,与常规回流提取法相比优势明显。     

Mechanical extraction

The mechanical screw press was the principal means of extracting vegetable oilseeds in the United States from the 1930s through the 1940s and 1950s. Then the utilization of solvent extraction cut drastically into their use for full extraction, but created a great demand for screw presses for prepressing of high oil content seeds for solvent extraction. However, use of the screw press for full extraction has been increasing over the years in the less developed countries, and is the main modern machine utilized for some products such as palm fruit. Today ever larger and more efficient machines are being developed for full extraction and pre-pressing of vegetable oilseeds and fruits.     

Comparison of membrane extraction with traditional extraction methods for biodiesel production

Three traditional methods for the refining step in biodiesel production were compared: (i) washing with distilled water; (ii) washing with acid (HCl); and (3) dissolving and extracting in a solvent (hexane or petroleum ether) and then washing with distilled water. Biodiesel with a high purity (97.5%) could be obtained by all three methods, but serious emulsification occurred during the refining processes, which led to high refining losses. A novel refining method was developed by using hollow fiber membrane extraction, and polysulfone was selected as the most suitable membrane. This process effectively avoided emulsification during refining and decreased the refining loss. The purity of the biodiesel obtained was about 99%; and other properties, such as density, kinematic viscosity, water content, and acid value, conformed to the standards.     

往复振动筛板萃取塔萃取机理研究进展

介绍了往复振动筛板萃取塔（RPEC）流体力学性能和传质性能研究现状。     

Solvent extraction of soybeans

The removal of edible oils from oilseeds was practiced by the Egyptians many centuries ago. Some of the developments leading to today’s worldwide extraction industry are discussed, and a brief history of the industry in the United States from 1940 to the present is included. The theory of solvent extraction is outlined in practical terms. Several types of solvent extraction and desolventizing systems are explained. Also, typical preparation and extraction processes for presscake, soybeans, and some high oil content seeds are illustrated. Some reasons for taking extra precautions in the preparation process and the desolventizing process when producing human edible soy protein products are explained. Energy conservation suggestions are included.     

Multistep extraction of coal

Unlike many natural and synthesized polymers, coal is a mixture of polyfunctional high-molecular-mass material. The usually observed limited extractability of coal is attributed to the disregard of various relatively strong intra- and intermolecular interactions and their co-operativity. Due to the polyfunctionality, ionic, charge-transfer and so-called π-π interactions are present, and their abundances are highly rank-dependent. Such relatively strong interactions are not completely solvated in a single step with any solvent. In this paper, multistep extraction was studied to solvate these interactions. Pyridine was mostly used after treatments to disrupt these interactions without breaking covalent bonds. Much larger pyridine extractability was obtained compared to a single step extraction. As solubilization or extraction is the first step to characterize coal, caution is advised against the limited extractability obtained by conventional procedures.