Query: caffeine extraction

title: Caffeine Extraction from Raw and Roasted Coffee Beans.
abstract: Coffee is a stimulant, psychoactive, popular daily beverage, and its caffeine affects human physiological health and behavior. These important issues prompted us to study caffeine extraction from both the raw and roasted coffee beans of 3 types at different temperatures. A hemispheric model is developed to simulate the extraction process of the caffeine from the coffee beans of hemisphere is proposed. The experimental data are in good agreement with the predicted model. The effective diffusivities of caffeine in both the raw and roasted beans increase with temperature in all 3 types. An incubation period, decreasing with increasing temperature, is observed in all samples studied. Caffeine extraction in roasted beans is more rapid than that for the raw beans and the time difference is significant at low temperatures. In both the raw and roasted samples, caffeine diffusion in the raw beans and the incubation behavior are thermally activated processes. Single activation energies are obtained for diffusion within the extraction temperature range for all beans tested with the exception of one type of the coffee beans, Mandheling, which exhibits 2 activation energies in raw samples. The surface energies of the epidermis of the raw beans and roasted beans obtained from the contact angle measurements are used to interpret the difference of incubation periods.  This study has a potential application to the decaffeinated coffee industry.Caffeine affects human physiological health and behavior so that caffeine extraction from coffee beans of different types at different temperatures is important for product refining and customers.

title: Effects of processing parameters on the caffeine extraction yield during decaffeination of black tea using pilot scale supercritical carbon dioxide extraction technique
abstract: In this pilot scale study supercritical carbon dioxide (SCCO2) extraction technique was used for decaffeination of black tea. Pressure (250, 375, 500 bar) extraction time (60, 180, 300 min) temperature (55, 62.5, 70 degC) CO2 flow rate (1, 2, 3 L/min) and modifier quantity (0, 2.5, 5 mol% were selected as extraction parameters. Three level and five factor response surface methodology experimental design with a Box Behnken type was employed to generate 46 different processing conditions. 100% of caffeine from black tea was removed under two different extraction conditions; one of which was consist of 375 bar pressure, 62.5 degC temperature, 300 min extraction time, 2 L/min CO2 flow rate and 5 mol% modifier concentration and the other was composed of same temperature, pressure and extraction time conditions with 3 L/min CO2 flow rate and 2.5 mol% modifier concentration. Results showed that extraction time, pressure, CO2 flow rate and modifier quantity had great impact on decaffeination yield.

title: Isolation of gallic acid, caffeine and flavonols from black tea by on line coupling of pressurized liquid extraction with an adsorbent for the production of functional bakery products
abstract: The objective of this work was to evaluate the on line coupling of pressurized liquid extraction with an adsorbent for the simultaneous extraction and separation of flavonols of black tea, producing a concentrated extract that could be used as ingredient for the production of functional bakery products. After the evaluation of different adsorbents, extraction temperatures and solvents, a two stage process was developed which was capable of producing three extracts: one with high concentration of gallic acid (78.97 5.49 mg/L) another one with high concentration of caffeine (109.72 3.15 mg/L) and a highly concentrated flavonol extract (322.0 4.50 mg/L) The developed method uses greener solvents (water and ethanol) and is capable of producing higher flavonol ~50% yields than conventional methods. The introduction of the flavonol extract in the dough can be used for the development of functional bakery since compounds were stable under processing conditions.

title: Aqueous two phase (polyethylene glycol sodium sulfate) system for caffeine extraction: Equilibrium diagrams and partitioning study
abstract: Environmental friendly methods for liquid liquid extraction have been taken into account due to critical conditions and ecotoxicological effects potentially produced by organic solvents applied in traditional methods. Liquid liquid extraction using aqueous two phase systems (ATPSs) presents advantages when compared to traditional liquid liquid extraction. (Polyethylene glycol (PEG) sodium sulfate water) ATPS was applied to study partition of caffeine. Binodal curves for ATPSs composed of PEG of different molecular weights (400 g mol 1 4000 g mol 1 and 6000 g mol 1 sodium sulfate water were determined by cloud point method at three different temperatures (293.15, 313.15 and 333.15) K. Liquid liquid equilibrium (LLE) data (tie lines, slope of the tie line and tie lines length) were obtained applying a gravimetric method proposed by Merchuck and co workers at the same temperatures for aqueous (PEG 400 sodium sulfate) and aqueous (PEG 400 sodium sulfate caffeine) systems. Reliability of the experimental tie line (TL) data was evaluated using the equations reported by Othmer Tobias and satisfactory linearity was obtained. Concerning to aqueous (PEG sodium sulfate) system, the results pointed out that the higher PEG molecular weight the largest is the heterogeneous region. Moreover, temperature showed not to be relevant on binodal curves behavior, but it influenced on tie line slopes. Partitioning of caffeine in aqueous (PEG 400 sodium sulfate) system was investigated at different temperatures and tie lines lengths (TLLs) It was shown that the partitioning was depended on the temperature and TLL and at all conditions studied the salting out effect displayed higher influence leading caffeine partition preferentially into the PEG rich (top) phase.

title: Magnetic solid phase extraction of trace paracetamol and caffeine in synthetic urine and wastewater samples by a using core shell hybrid material consisting of graphene oxide/multiwalled carbon nanotube/Fe3O4/SiO2
abstract: A new hybrid material was synthesized including magnetic graphene oxide/multiwalled carbon nanotube core shell (GO/MWCNT/Fe3O4/SiO2) and used as magnetic solid phase extraction adsorbent for separation and pre concentration of paracetamol and caffeine subsequent detection by high performance liquid chromatography. The morphology, composition, and properties of the synthesized hybrid material was characterized by Fourier transform infrared spectrometry, Raman spectrometry, X ray diffraction spectrometry, scanning electron microscopy, mapping photographs and BET surface area analysis. The experimental variables on the extraction efficiency were studied and optimized. The optimum conditions for quantitative extraction of paracetamol and caffeine were obtained as of adsorbent amount, 70 mg; pH, 8.0; and elution with 1 mL of methanol by vortex mixer for 60 s. Validation experiments showed that the developed method had good linear ranges 5 800 ng mL 1 for caffeine and 10 1000 ng mL 1 for paracetamol, respectively. The limits of detection were found as 1.48 and 3.32 ng mL 1 for caffeine and paracetamol, respectively. The accuracy of the developed magnetic solid phase extraction method was proved by addition recovery tests by using model solutions and the developed method was successfully applied for the determination of paracetamol and caffeine in synthetically prepared urine and waste water samples.

title: Simultaneous determination of six antipsychotics, two of their metabolites and caffeine in human plasma by LC MS/MS using a phospholipid removal microelution solid phase extraction method for sample preparation.
abstract: A simple and sensitive liquid chromatography tandem mass spectrometry method was developed and validated in human plasma for the simultaneous determination of aripiprazole (ARI) and its metabolite dehydro aripiprazole (DARI) olanzapine (OLA) risperidone (RIS) paliperidone (PAL) quetiapine (QUE) clozapine (CLO) and caffeine (CAF) CAF is included to the method because it can have an influence on drug metabolism due to competitive inhibition. The above mentioned compounds and their isotope labeled internal standards were extracted from 200 uL human plasma samples by both, effective phospholipids eliminating three step microelution solid phase extraction (u SPE) and protein precipitation (PPT) for comparison. A combination of formic acid (0.2% acetonitrile (pH 3.0; 65:35, v/v) was used as mobile phase and the chromatogram was run under gradient conditions at a flow rate of 0.6 mL/min. Run time lasted 6 min, followed by a re equilibration time of 3 min. All analytes were monitored by mass spectrometric detection operating in multiple reaction monitoring mode and the method was validated covering the corresponding therapeutic ranges: 0.18 120 ng/mL for ARI, 0.25 80 ng/mL for DARI, 1.00 100 ng/mL for OLA, 0.70 60 ng/mL for RIS, 0.20 30 ng/mL for PAL, 0.50 160 ng/mL for QUE, 0.50 1000 ng/mL for CLO, and finally 1200 3700 ng/mL for CAF. The method was validated based on the recommendations of regulatory agencies through tests of precision, accuracy, extraction recovery, identity confirmation, trueness, matrix effect, process efficiency, stability, selectivity, linearity and carry over effect fulfilling the guideline requirements. Our u SPE method results in the elimination of more than 99% of early eluting and more than 92% of late eluting phospholipids compared to PPT. Additionally, the method was successfully applied for quantifying ARI and OLA plasma concentrations from healthy volunteers.

title: Caffeine Extraction from Tea and Coffee

title: The kinetics of the extraction of caffeine from guarana seed under the action of ultrasonic field with simultaneous cooling
abstract: The kinetics of isothermal extraction of caffeine from guarana seed under the action of ultrasonic field with simultaneous cooling (UESC) was investigated. The isothermal kinetics curves were measured at temperatures range T 17 58degC. Using the model fitting method it was determined that the kinetics of caffeine extraction can be described by a theoretical Jander three dimensional diffusional model. The values of the rate constant were calculated for different temperatures, as well as the kinetic parameters (activation energy (Ea) and pre exponential factor (lnA) Based on the results obtained, it is concluded that the rate constants of caffeine extraction under UESC are about 2 times higher in comparison to the values obtained for the extraction in the conditions of conventional heating (CH) The activation energy of the caffeine extraction under the UESC E a UESC 19.4 kJ mo l 1 \left( E_{\text{a}\text{UESC}=19.4\\text{kJ}\cdot \text{mo}\text{l} 1} \right)$is lower than the values are for CH E a CH 21.8 kJ mo l 1 \left( E_{\text{a}\text{CH}=21.8\\text{kJ}\cdot \text{mo}\text{l} 1} \right) Energy consumption for UESC is four times lower than for CH conditions. It is shown that there is a linear correlation relationship between kinetic parameters obtained for UESC and CH conditions. The changes in the values of kinetic parameters are explained by the model of selective transfer of energy from the reaction system to the reactant molecules.

title: Deep eutectic solvents used as the green media for the efficient extraction of caffeine from Chinese dark tea
abstract: In recent years, more and more attention are paid to the green media in the extraction field. Deep eutectic solvents (DESs) are considered as excellent substitutes to traditional organic solvents and ionic liquids (ILs) In this work, DESs were used to extract caffeine from Chinese dark tea (CDT) then caffeine was recovered from the crude DES extract using macroporous resins. The factors affecting the solid liquid extraction, including DES concentration, liquid solid ratio, extraction time, extraction temperature, and system pH were studied in the single factor experiments. The Kamlet Taft polarity parameters of DESs were determined to analyze the proper hydrogen bond interaction between DESs and caffeine. Then the major factors of DES concentration, liquid solid ratio, and extraction time were optimized by response surface methodology (RSM) The results showed that the maximum extraction yield of 26.78 mg/g were obtained using the DES choline chloride lactic acid (ChCl LA) as extractant under the optimized conditions. Moreover, the kinetics model of caffeine extraction was established using the Fick's Second Law, the experimental results were well fitted by this model. This extraction of caffeine from CDT using DESs is much simpler and environmentally friendly with low cost and high extraction efficiency.

title: Simultaneously Extraction of Caffeine and Chlorogenic Acid from Coffea canephora Bean using Natural Deep Eutectic Solvent Based Ultrasonic Assisted Extraction
abstract: NADES is an alternative solvent in the extraction of metabolites from plants which has many environmental benefits, such as low toxicity, biodegradability, can dissolve polar and non polar compounds, low costs and simple preparation.  This study aims to determine the effect of natural deep eutectic solvent based ultrasonic assisted extraction (NADES UAE) on enrichment of caffeine and chlorogenic acid in extract from green coffee beans (Coffea canephora)  The powders were extracted using NADES UAE method in several types of extraction condition, including the composition of NADES, water addition in NADES and extraction time. Caffeine and chlorogenic acid content were analyzed using HPLC, reverse phase system and C18 ODS 3 column.  The highest of caffeine and chlorogenic acid content was respectively, 7.89 mg/g and 28.62 mg/g (composition of NADES betaine: sorbitol [1:1.2] ratio and NADES water addition [1:2] ratio for 30 min)  This research showed that the composition of NADES, extraction time and water addition are important parameter in extracting caffeine and chlorogenic acid content in green coffee beans.