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Extraction Pressure (extraction + pressure)

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Chemistry	100%

Selected Abstracts

Extraction and Removal of Caffeine from Green Tea by Ultrasonic-Enhanced Supercritical Fluid

JOURNAL OF FOOD SCIENCE, Issue 4 2010
Wei-Qiang Tang
ABSTRACT:, Low-caffeine or caffeine-removed tea and its products are widely welcomed on market in recent years. In the present study, we adopt ultrasonic-enhanced supercritical fluid extraction process to remove caffeine from green tea. An orthogonal experiment (L16 (45)) was applied to optimize the best removal conditions. Extraction pressure, extraction time, power of ultrasound, moisture content, and temperature were the main factors to influence the removal rate of caffeine from green tea. The 5 factors chosen for the present investigation were based on the results of a single-factor test. The optimum removal conditions were determined as follows: extraction pressure of 30 MPa, temperature at 55 °C, time of 4 h, 30% moisture content, and ultrasound power of 100 W. Chromatogram and ultraviolet analysis of raw material and decaffeinates suggests that under optimized conditions, the caffeine of green tea was effectively removed and minished without damaging the structure of active ingredients in green tea. [source]

Quantification of seed oil from species with varying oil content using supercritical fluid extraction

PHYTOCHEMICAL ANALYSIS, Issue 6 2008
Charlotte E. Seal
Abstract Introduction: The quantity and composition of seed oil affects seed viability and storability and hence the value of a species as a resource for nutrition and plant conservation. Supercritical fluid extraction with carbon dioxide (SFE-CO2) offers a rapid, environmentally friendly alternative to traditional solvent extraction. Objective: To develop a method using SFE-CO2 to quantify the seed oil content in a broad range of species with high to low oil contents. Methodology: Seed oil was extracted using SFE-CO2 from four crop species representing high, medium and low oil content: Helianthus annuus, Asteraceae, with ca. 55% oil; Brassica napus, Brassicaceae, with ca. 50% oil; Glycine max, Fabaceae, with ca. 20% oil; and Pisum sativum, Fabaceae, with ca. 2% oil. Extraction pressures of 5000, 6000 and 7500 psi and temperatures of 40, 60 and 80°C were examined and a second step using 15% ethanol as a modifier included. Oil yields were compared with that achieved from Smalley Butt extraction. The optimised SFE-CO2 method was validated on six species from taxonomically distant families and with varying oil contents: Swietenia humilis (Meliaceae), Stenocereus thurberi (Cactaceae), Sinapis alba (Brassicaceae), Robinia pseudoacacia (Fabaceae), Poa pratensis (Poaceae) and Trachycarpus fortunei (Arecaceae). Results: The two-step extraction at 6000 psi and 80°C produced oil yields equivalent to or higher than Smalley Butt extraction for all species, including challenging species from the Brassicaceae family. Conclusion: SFE-CO2 enables the rapid analysis of seed oils across a broad range of seed oil contents. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Extraction and Removal of Caffeine from Green Tea by Ultrasonic-Enhanced Supercritical Fluid

Characterization via liquid chromatography coupled to diode array detector and tandem mass spectrometry of supercritical fluid antioxidant extracts of Spirulina platensis microalga

JOURNAL OF SEPARATION SCIENCE, JSS, Issue 9-10 2005
Jose A. Mendiola
Abstract Spirulina platensis microalga has been extracted on a pilot scale plant using supercritical fluid extraction (SFE) under various extraction conditions. The extraction yield and the antioxidant activity of the extracts were evaluated in order to select those extracts with both the highest antioxidant capacity and a good extraction yield. These extracts were characterized using LC coupled to diode array detection (DAD) and LC coupled to mass spectrometry (MS) with two different interfaces, atmospheric pressure chemical ionization (APCI) and electrospray (ESI) which allowed us to perform tandem MS by using an ion trap analyzer. The best extraction conditions were as follows: CO2 with 10% of modifier (ethanol) as extraction solvent, 55°C (extraction temperature) and 220 bar (extraction pressure). Fractionation was achieved by cascade depressurization providing two extracts with different activity and chemical composition. Several compounds have been identified in the extracts, corresponding to different carotenoids previously identified in Spirulina platensis microalga along with chlorophyll a and some degradation products. Also, the structure of some phenolic compounds could be tentatively identified. The antioxidant activity of the extracts could be attributed to some of the above mentioned compounds. [source]

Decontamination of organochlorine pesticides in Radix Codonopsis by supercritical fluid extractions and determination by gas chromatography

BIOMEDICAL CHROMATOGRAPHY, Issue 9 2006
Chunjie Zhao
Abstract A method involving depuration of 12 organochlorine pesticides (OCPs) from Radix codonopsis was developed using supercritical fluid extraction (SFE). The pesticides investigated in the study included , -, , -, , - and , -benzene hexachloride, PCNB (pentachloro-nitrobenzene), PCA (pentachloroaniline), HEPT (heptachlor), MPCPS (methyl-pentachlorophenyl sulfide), pp,-DDE [1,1-dichloro-2, 2-bis(p -chlorophenyl) ethylene], op,-DDT [1,1,1-trichloro-2-(o -chlorophenyl)-2-(p -chlorophenyl)ethane], pp,-DDD [1,1-dichloro-2-2-bis(p -chlorophenyl)ethane] and pp,-DDT [1,1,1-trichloro-2,2-bis(p -chlorophenyl)ethane]. A series of experiments was conducted to optimize the final extraction conditions as follows: pure CO2, extraction pressure 15 MPa, extraction temperature 60°C, extraction time 20 min and flow rate 55 mL/h. A GC method with electron capture detection was employed for the determination of the OCPs in Radix codonopsis. An HPLC method was developed for the quantitative determination of active constituents. SFE was used to remove the organochlorine pesticide from Radix codonopsis. The results showed that at least 93.5% of the organochlorine pesticide residues in the herb sample were removed by SPE, while 95.0% of the active constituent marker (atractylenoide III) remained. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Supercritical fluid extraction for the separation of organochlorine pesticides residue in Angelica sinensis

BIOMEDICAL CHROMATOGRAPHY, Issue 7 2002
Chunjie Zhao
A method involving the simultaneous extraction and separation of 12 organochlorine pesticides (OCPs) from Angelicae sinensis was developed using supercritical fluid extraction (SFE). The pesticides in the study were ,-, ,-, ,- and ,-benzene hexachloride, PCNB (pentachloro- nitrobenzene), PCA (pentachloroaniline), HEPT (heptachlor), MPCPS (methyl-pentachlorophenyl sulfide), pp,-DDE [1,1-dichloro-2,2-bis (p -chlorophenyl) ethylene], op,-DDT [1,1,1,-trichloro-2-(o -chlorophenyl)-2-(p -chlorophenyl) ethane], pp,-DDD [1,1-dichloro-2,2-bis(p -chlorophenyl) ethane], and pp,-DDT [1,1,1,-trichloro-2,2-bis (p -chlorophenyl)ethane]. The extraction conditions were optimized as follows: pure CO2, extraction pressure 15 MPa, extraction temperature 60°C, extraction time 20,min, and flow-rate 1.5,mL/min. A GC method with electron capture detection was employed to determine the OCPs in Angelicae sinensis. An HPLC method was developed for the quantitative determination of active constituents. The SFE provided high decontamination rate of OCPs and low loss of active constituents in Angelicae sinensis. Copyright © 2002 John Wiley & Sons, Ltd. [source]