Extraction of caffeine

Copyright 2005 Wiley-VCH Verlag GmbH Co. KGaA, Weinheim ISBN 3-527-30721-4 

Today caffeine extraction using SCCO2 is the most commonly operated technology and, besides the more expensive Swiss Water process (using only water - saturated with the coffee s own sugars and pephdes - as an extracting agent [12]), it is the only one which is considered to be sustainable. 

---

Bejr, V., Extraction of caffeine from green grain coffee, Czech., 184,966, 1978. (CA94 190554v)... 

Roselius, L., Kurzhals, H. A., Hubert, P., Selective extraction of caffeine from plant materials, Ger. Offen. 2,727,191, 1978. (CA90 85545n)... 

Total caffeine consumption will vary with a number of factors that are often difficult to disentangle. For caffeine exposure attributable to coffee, this includes brewing method and preparation type of coffee (Arabica, Robusta, instant), averaging to 1.3% caffeine for roasted beans 39 brand of coffee size of coffee cup and the volume of added ingredients, such as milk, cream sweeteners, and syrups. There are several different brewing or preparation techniques by which coffee can be prepared. Most notably, they differ in their final extraction of caffeine depending on the process. Filter coffee or automatic drip coffee results in approximately 97 to 100% caffeine extraction 37 however, regional differences in the volume of coffee... 

While percolators were long used and the most common method of coffee preparation up to 1975 (51%), automatic drip machines have steadily increased to be the method used for nearly half of all coffee prepared in 1981,41 as compared to only 7% automatic drip in 1975. This trend does impact caffeine exposure, as the different preparation methods have differential extraction of caffeine from the coffee that is used. 

Flow rate and extraction time. No report was found for the effect of flow rate in the extraction of phytochemicals from herbs. Extractions at lower pressures and/or temperatures required prolonged time and large amounts of CO2 to achieve the same yield as reported for the extraction of caffeine, theophylline, and theobromine from mate tea leaves (Saldana and others 1999,2002a). 

Mohamed RS, Saldana MDA, Zetzl C, Mazzafera P and Brunner G. 2002. Extraction of caffeine, theobromine, and cocoa butter from Brazilian cocoa beans using supercritical CO2 and ethane. Ind Eng Chem Res 41(26) 6751-6758. 

Saldana MDA. 1997. Extraction of caffeine, trigonelline and chlorogenic acid from Brazilian coffee beans using supercritical CO2 MSc. Thesis, UNICAMP, Campinas, Brazil. 

Supercritical carbon dioxide (SCCO2) is a well-estabhshed solvent for applications in extraction processes. During the last 40 years, there has been an implementation of large-scale processes, e.g., the extraction of caffeine [6] and the isolation of hop extracts from raw plant material [37]. These examples show that the usage of this supercritical fluid (pc = 73.8 bar, Tc = 31.1 °C) is a state of the art operation in process technology. 

Compare the following excerpts that describe the process of recrystallization for product purihcation. The hrst excerpt is adapted from an undergraduate laboratory experiment involving the extraction of caffeine from tea leaves. The last two, written for expert audiences, are taken from articles in The Journal of Organic... 

SCFs are widely used in small-scale laboratory extraction and analysis and are already established for large-scale extraction of caffeine from coffee, flavors from hops, and many other such uses with plant sizes up to 50,000 tons per year throughput. A Philip Morris semicontinuous denicotinization plant is said to employ pressure chambers of 1.5-m diameter and 5-m height. The outlet gas is passed through activated carbon and recycled. ... 

Dry cleaning Chlorinated solvents Fire extinguisher Flame retardants Extraction of caffeine Hexane... 

Duan, W., X. Zhou, and J. Zhou. 2006. Extraction of Caffeine with Annular Centrifugal Contactors. Solvent Extr. IonExch. 24(2), 251-259. 

One of the most well known uses of SCCO2 is in the extraction of caffeine from coffee. This is carried out industrially on a huge scale producing many thousands of tons of decaffeinated coffee per year. New uses of SCCO2 for synthesis on an industrial scale are slowly becoming established, particularly where additional benefits, such as a higher purity product or a desirable physical property result (Beckman, 2004 Jessop and Leitner, 1999 Oakes et al., 2001). 

Extraction process 5 Extraction of Caffeine from tealeaves... 

Brunner et al. [3] used shells from the production of cacaomass having a composition of 1 % theobromine, 0,1 % caffeine, 5 % fat and 8 % water They are stating that theobromine can be extracted from the shells to some extend without adding water but for the extraction of caffeine one needs to increase the moisture content to about 50 %. In all cases large quantities of solvent are needed. Being a waste product and used as source for the xanthines only the content of butter has no importance. 

Solubilitiesattemperaturesand pressures above the critical values of the solvent liave important applications for supercritical separation processes. Examples are extraction of caffeine from coffee beans and separation of asplraltenes from heavy petroleum fractions. For a typical solid/vapor equilibrium (SVE) problem, tire solid/vapor saturation pressure P is very small, and the saturated vapor is for practical purposes an ideal gas. Hence 0 for pure solute vapor at this pressure is close to unity. Moreover, exceptfor very low values of the system pressure P, the solid solubility yj is small, and can be approximated by j, the vapor-phase fugacity coefficient of the solute at infinite dilution. Finally, since is very small, the pressure difference P — in the Poyntingfactor is nearly equal to P at any pressure where tins factor... 

SPME can also be used to extract target analytes from food and drug samples. Thus, it has been employed for the extraction of caffeine from coffee and tea [225], and for that of volatile impurities in drugs. Headspace SPME has also been tested for flavour analysis in foods. Thus, the SPME/GC/TOF-MS tandem was successfully used for the rapid analysis of volatile flavour compounds in apple fruit. The sample (300-450 g of apple) was subjected to static headspace sampling for 4 6 h in order to allow the volatiles... 

Due to the relative success of the pure component solubility studies, the same series of experiments were carried out using the complex seed material. Three systems were investigated to evaluate the ability of supercritical fluids to extract monocrotaline from the seeds of Crotalaria spectabilis. Pure carbon dioxide was studied with the expectation that the oils would be preferentially extracted. Ethanol was added as a co-solvent to increase the solubility of monocrotaline. Also, due to its success in the extraction of caffeine and nicotine, water was used as a co-solvent. 

Carbon Dioxide - Water - Crotalaria Spectabilis System. Water has been used as a CO-solvent in the extraction of caffeine from coffee and nicotine from tobacco. To extract caffeine from coffee beans, Zosel (3) recommended the pre-saturation of the carbon dioxide with water before passing the fluid through the coffee bean bed. In the case of nicotine from tobacco, Hubert and Vitzthum (2) first soaked the tobacco with up to 25 wt.% water and subsequently passed carbon dioxide through the tobacco bed. The water acted as a co-solvent as it saturated the fluid phase. Both of these processes have proven highly selective toward the alkaloids present in the plant material. Therefore, water was used as a co-solvent in the present study. 

Few investigations are available on liquid natural materials. One example is the extraction of caffeine from aqueous phases. Phase transitions as well as the hydraulic behaviour of packed and unpacked columns have been investigated (1-4). 

Farrington, K Magner, E. Regan, F., Predicting the performance of molecularly imprinted polymers, Selective extraction of caffeine by molecularly imprinted solid phase extraction, Anal. Chim. Acta. 2006, 566, 60-68... 

Bakerbond Application Note FF-006 Extraction of Caffeine, Saccharin, and Sodium Benzoate from Diet Cola. Published with the permission of J. T. Baker, Inc. (see Suggested Reading, Chapter 1). 

The most common use of scC02 is in the extraction of caffeine from coffee or tea, nicotine from tobacco, and essential oils from plants. The isolation of products is simple, with the evaporation of the solvent with no residue. Another important application is in supercritical fluid chromatography (SFC). 

Each patent has somewhat different features and claims. We select one patent for more detailed discussion to highlight certain technical facets of the process. First we explain the (often misunderstood) effect of water on the extractability of caffeine by selective supercritical carbon dioxide. A number of references report that dry carbon dioxide cannot extract caffeine from dry coffee, either green or roasted, but moist carbon dioxide can. The inability of dry carbon dioxide to extract caffeine from coffee should not be misconstrued to mean that dry carbon dioxide cannot dissolve neat caffeine. This same moist-versus-dry effect is experienced if, for example, methylene chloride is used to extract caffeine from coffee. Dry methylene chloride cannot decaffein-ate dry coffee but moistened coffee can be decaffeinated. It is thought that the caffeine is chemically bound in a chlorogenic acid structure present in the coffee bean. Thus, water somehow acts as a chemical agent it frees caffeine from its bound form in the coffee matrix in both the carbon dioxide and the methylene chloride processes. 

Mar. 10, 1981 4,255,458 Method for the selective extraction of caffeine from vegetable materials HAG Aktiengsellschaft... 

Oct. 25, 1983 4,411,923 Process for the extraction of caffeine supercritical solutions HAG Aktiengesellschaft... 

---