Supercritical CO2 extraction of rice bran

Extraction of rice bran lipids with supercritical carbon dioxide (SC-CO₂) was performed. To investigate the pressure effect on extraction yield, two isobaric conditions, 7000 and 9000 psi, were selected. A Soxhlet extraction with hexane (modified AOCS method Aa 4–38; 4 h at 69°C) was also conducted and used as the comparison basis. Rice bran with a moisture content of 6%, 90% passable through a sieve with 0.297 mm opening, was used for extraction. A maximum rice bran oil (RBO) yield of 20.5%, which represents 99+% lipid recovery, was obtained with hexane. RBO yield with SC-CO₂ ranged between 19.2 and 20.4%. RBO yield increased with temperature at isobaric conditions. At the 80°C isotherm, an increase in RBO yield was obtained with an increase in pressure. The pressure effect may be attributed to the increase in SC-CO₂ density, which is closely related to the value of the Hildebrand solubility parameter. RBO extracted with SC-CO₂ had a far superior color quality when compared with hexane-extracted RBO. The level of sterols in SC-CO₂-extracted RBO increased with pressure and temperature.     

Supercritical CO2 extraction of triterpenes from rosemary leaves: Kinetics and modelling

The pentacyclic triterpene α,β-amyrin is a promising bioactive natural product. Supercritical fluid extraction and fractionation are used to obtain pentacyclic triterpenes compounds from dried rosemary leaves. Experiments were conducted at 50°C and 180 bar, and the fractionation of the extract was accomplished in two separators. The shift to a diffusion-controlled regime occurred when 65% of the total oil was extracted. The moments analysis of kinetic curves indicated that the contribution of the axial dispersion, the external transfer and the internal transfer were 9.16%, 80.24% and 10.58%, respectively. The overall extraction curve was represented using three mathematical models.     

超临界二氧化碳萃取葡萄籽油的研究

葡萄籽油中富含亚油酸和其它不饱和脂肪酸,具有较高的食用和药用价值。传统的葡萄籽油提取方法存在着收率低和溶剂残留的问题。今基于对酿酒过程中废弃葡萄籽的开发利用,探讨了采用绿色洁净分离技术——超临界流体萃取技术从废弃葡萄籽中萃取葡萄籽油的可行性,重点考察了萃取温度、萃取压力、CO2用量及不同原料对葡萄籽油产率的影响。研究表明萃取压力对产率的影响较温度显著,实验确定适宜工艺条件为萃取温度55C,萃取压力30MPa。此条件下以张裕酒厂提供的籽为原料所得产率为9.71%,同时气相色谱分析表明,葡萄籽油产品中含有72.05%的亚油酸。另外,分别以三种不同来源的葡萄籽为原料进行实验,研究显示,葡萄籽油产率随原料不同而存在一定差异,产率较高者可达13.51%。     

The Solubility of Styrene from Polystyrene in Supercritical CO2

The solubility of styrene from polystyrene in supercritical carbon dioxide is measuredat 323 K,333 K,and 343 K in the pressure range from 12 to 28 MPa.Based on the associationconcept and the theory of dense gas sorption in polymers,a displacement and association mechanismon supercritical fluid extraction of the monomer from the polymer is proposed.And,a novel math-ematical model for correlating the solubility data obtained from the experiments is also proposed inthe paper.     

丁香油的超临界CO2萃取及其微胶囊的制备

在70℃和10 MPa条件下通过对丁香花蕾进行超临界CO2萃取得到丁香油,萃取率达19%～21%.气质联用分析结果表明,丁香油中主要化学成分包括丁香酚、β-石竹烯和乙酰基丁香酚等.以丁香油为囊芯,探讨利用干酵母细胞作为囊壁材料制备微胶囊的可行性.通过正交试验考察了包埋温度、包埋时间、丁香油与干酵母配比(芯材比)对微胶囊化丁香油的影响.结果表明,在包埋温度70℃、包埋时间9 h和芯材比为1∶1(w/w)的条件下,微胶囊中丁香油包埋率达到41.26%.通过扫描电镜观察,丁香油微胶囊呈规则的球形,大小均一,颗粒直径在2.0～4.0 μm.在100℃下对经微胶囊化的丁香油加热20 h,其挥发率只有15.04%,远低于相同条件下丁香油的挥发率(58.29%).这种新型的微胶囊化方法,具有制备过程简单、包埋率高和不引入有机溶剂的优点.     

提取野菊花中的精油

采用超临界CO₂萃取技术,研究了从野菊花中提取精油的工艺并鉴定其主要化学成分。对影响超临界CO₂萃取精油的各因素进行了单因素试验研究,得到较适宜的萃取工艺条件,萃取温度 35℃、分离温度 30℃、萃取时间 90 min、萃取压力 25 MPa、CO₂流量为 30 kg/h。在上述萃取工艺条件下,精油得率 9.65%。经GC-MS分析鉴定了野菊花精油成分43个,主要是萜类及其含氧衍生物、烷烃类化合物和酯类化合物等。     

Supercritical carbon dioxide extraction,purification, and characterization of wax from sorghum and sorghum by-products as an alternative natural wax

The objective of this work was to obtain high purity natural wax from sorghum and by-products of sorghum processing (sorghum dried distillers grains with solubles [DDGS] and sorghum bran) using a green process based on supercritical carbon dioxide (SC-CO₂). SC-CO₂ extractions were carried out at varying temperatures (50, 70°C) and pressures (30, 40 MPa) at a CO₂ flow rate 1 L/min for 120 min. Significantly higher wax yield (4.9%) from DDGS was obtained by SC-CO₂ at 40 MPa/70°C compared with whole kernel (0.6%) and bran (3.3%) (p < 0.05). The yield of the extracts obtained by SC-CO₂ extraction was higher than that of the conventional hexane extraction for all three sorghum sources. The highest fraction of wax in the SC-CO₂ extracts was obtained from whole kernel extracts (89%), whereas it was 53.3% from the DDGS and 26.8% from the bran at the same extraction conditions. SC-CO₂ and hexane extracts from sorghum whole kernel shared a similar melting peak temperature of 76.3–77.9 and 79.7°C, respectively, while DDGS and bran extracts by SC-CO₂ showed a much lower melting temperature in the range of 50.7–61.9°C, indicating the presence of lower melting point components such as triacylglycerols. However, the melting points of the DDGS and bran extracts after ethanol purification were significantly increased with the observed peak temperature of 80.8 and 82.0°C, respectively. While the wax yield from DDGS and bran was higher than that of whole kernel, the sorghum whole kernel feedstock was found to be a more feasible feedstock to obtain higher purity wax.     

鲜花精油和浸膏的超临界CO_2萃取进展

该文对国内外植物精油和浸膏的提取方法作了概述,包括传统方法(水蒸馏法和有机溶剂浸提法)和新型清洁方法〔微波诱导法、吸附法、水扩散法、分子蒸馏、超临界水萃取、液体CO2萃取和超临界CO2(SC CO2)萃取〕。介绍了SC CO2萃取的原理和优势,详细地说明了SC CO2对精油选择性萃取的较优条件、蜡和精油的传质机理、多级萃取除蜡等。重点将现有的SC CO2萃取强化方法———快速降压法、夹带剂法和溶胀预处理法进行较详细的总结。引用文献34篇。     

超临界CO2从留兰香油中萃取香芹酮

用超临界CO2萃取法对留兰香毛油进行了萃取香芹酮的初步研究。工作是在实验室的小型装置上进行的。文中对实验装置和操作条件作了介绍。实验表明:在萃取塔底为50℃、塔顶为85℃,程序升压,使压力从8MPa升至13MPa时,可获得香芹酮质量分数为97%的馏分。     

提取花生壳中多酚类物质

采用超临界CO₂萃取技术,研究了从花生壳中提取多酚类物质的工艺。对影响超临界CO₂萃取多酚的各种因素进行了单因素试验研究,得到较适宜的萃取工艺条件为:萃取温度60℃、萃取时间2 h、萃取压力20 MPa、夹带剂用80%乙醇(体积分数,其用量为每克原料4 mL)。在上述较适宜的萃取工艺条件下,多酚类物质得率为6.19%。     

超临界CO_2萃取在中药现代化研究中的应用

综述了近年来超临界CO2萃取技术在中药现代化中的最新研究进展,并展望了其应用前景。     

超临界CO2萃取牛至挥发油的工艺研究

采用超临界CO2萃取牛至药材中的挥发油,以挥发油产品中两种主要有效成分的质量总和为考察指标,以萃取压力、萃取温度、萃取时间、夹带剂浓度及夹带剂流量为考察因素进行正交实验,优选最佳的萃取工艺条件。最佳的萃取工艺条件为:萃取压力为25 MPa、萃取温度为55℃、萃取时间为2.5 h、75%乙醇为夹带剂、夹带剂流量为0.02mL/min、CO2流量为1 L/min,在此实验条件下,产品中两种主要有效成分的质量总和平均为0.141 24 g。优选得到的萃取工艺可靠、简便易行、稳定性好。     

超临界二氧化碳精制辣椒红色素的研究

采用超临界二氧化碳萃取技术对有机溶剂萃取的辣椒红粗提物进行提纯、精制,制备高色价、高质量的辣椒红色素产品。研究了萃取压力、萃取时间等因素对产品色价及收率的影响,添加夹带剂对萃取效果的影响,得到较佳的工艺条件为：萃取压力17MPa(添加夹带剂)、14MPa(添加夹带剂),萃取时间4h。结果：未添加夹带剂产品色价由原来的60提高到150,产品收率为93％;加有夹带剂的产品比未加夹带剂的产品色价高出20,产品收率高2％;辣素含量更低,基本无法检出：溶解性更好,无不溶物：脱辣、脱臭效果好,不含任何异味、杂味。     

固体在超临界二氧化碳中溶解度的关联与计算

精确的溶解度数据是超临界流体萃取工艺设备设计和操作条件选择的关键 ,本文采用Peng -Robinson状态方程对 15种固体在超临界CO2 中的溶解度数据进行了关联计算 ,溶解度的计算值与文献的实验值符合很好 ,其平均相对偏差均小于 10 %。     

超临界二氧化碳萃取中试装置的工艺改进

分析了目前国内使用的超临界流体萃取装置的不足,并对其进行了改进,设计出适合以二氧化碳为萃取介质的中试装置。超过34000h的试用结果表明：该装置使用简单、操作安全、密封可靠,能满足多种原料的萃取要求,总体性能与进口设备相当,但造价低于进口设备,具有较高的应用价值。     

Supercritical fluid extraction of oil from millet bran

Proso millet bran [Panicum miliaceum (L.)], variety Dakota White, was extracted with supercritical carbon dioxide (SC-CO₂) to yield crude oil. The effects of operating parameters (pressure, temperature, and specific solvent flow) and of features of the raw material (moisture content and particle size) on oil extraction were investigated. Complete de-oiling of ground millet bran pellets was achieved under 300 bar at 40°C with a specific solvent flow of 2–10 h⁻¹ within 200 to 500 min. Solvent requirements were 20–30 kg CO₂/kg raw material. Composition of crude SC-CO₂ oil extracted under optimal conditions, i.e., fatty acid profile, amount of unsaponifiables, tocopherols, free fatty acids, sterols, sterol esters, waxes, hydrocarbons, and phospholipids, was compared to that of crude oil obtained by petroleum ether extraction. These two oils were similar in terms of fatty acid profile and amount of free fatty acids, unsaponifiables, peroxides, and tocopherols. They differed in respect to phospholipids (present in petroleum etherextracted oil and absent in SC-CO₂ extracted oil), metals, and waxes (lower levels in SC-CO₂ extracted oil). The effects of extraction procedures on oxidative stability of crude SC-CO₂ oil were studied. Ensuring that all pieces of the extractor in contact with the oil were in stainless steel; cleaning the separator, i.e., washing with KOH, rinsing, purging with N₂ and CO₂, and heating; performing a couple of extractions before the main extraction; and achieving the extraction without interruption all positively influenced the oxidative stability of the oil. Conversely, increasing CO₂ purity above 99.5% had no effect. Oxidative stability of the SC-CO₂ oil extracted under these conditions was only slightly lower than that of the oil extracted with petroleum ether.     

超临界二氧化碳萃取在石油工业中的应用探究

随着化工工程的发展,超临界技术得以发展并被广泛的应用到了各个领域之中,尤其是石油化工行业。二氧化碳、乙醇、丙烯等气体都可作为流体萃取的溶剂,而在石油工业中,二氧化碳萃取具有独特的优势。对以二氧化碳为溶剂的超临界流体萃取技术在石油工业中的应用情况进行分析与探究。     

超临界CO2萃取红花药渣中挥发油和红色素

在0.5 L半连续装置上,考察了温度、压力、CO2流量及物料粒径等工艺条件对超临界CO2分级萃取红花水煮醇提药渣的影响,得到了红花挥发油和红花红色素,对红色素含量进行了测定,并同红花分级萃取进行了对比. 结果表明,温度、压力及CO2流量对分级萃取影响明显. 在考察范围内最佳工艺条件为：一级萃取温度35℃、压力9 MPa、CO2流量3.74 kg/h;二级萃取温度35℃、压力30 MPa、CO2流量3.74 kg/h. 在此条件下红花挥发油萃取率达2.74%,红色素相对收率达69.88%.     

超临界二氧化碳萃取生姜油实验研究与数值模拟

1 INTRODUCTION Supercritical fluid extraction (SFE) as an alter- native to conventional processes, such as solvent ex- traction and steam distillation for obtaining essential oils, is a novel technique especially attractive to the food, cosmetics and Pharmaceuticals industries. The extracts from SFE are free of solvent residues. In ad- dition, the process can be conducted at low tempera- ture, which is very important to preserve the quality of heat-sensitive products[1,2]. Ginger (Zing…     

超临界流体萃取技术在天然产物加工中的应用

论述了超临界流体萃取技术的重要性,对它在天然产物加工(特别是植物精油提取)中的最新应用研究进行了总结,讨论了它与传统分离方法相比较的优点,展望了它今后的发展方向和趋势。引用文献23篇。