Caffeine, extraction

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... 

C and pressures ranging from 10 to 40 MPa. The quantity of caffeine extracted increased with an increase in pressure, with this effect being more pronounced at 70°C than at 40°C (Saldana and others 2002a,b). One important aspect to consider while depressurizing the system is that this step might affect the breakage of the coffee beans (Saldana 1997). 

Purified, caffeine (Figure 4.1) is a white crystalline powder with a bitter taste. While caffeine is not particularly soluble in water, it is extracted from plant material with hot water. The longer the extraction period, the greater the amount of caffeine extracted. In plants, caffeine s purpose may be to discourage consumption by predators with its bitter taste and mild nervous system effects, but with humans it clearly has the opposite effect of encouraging consumption of the plant. 

Explanation of the caffeine-extraction plants, most of the commercial plants produce at least two different products. Plants were consolidated to what is thought to be the main product. Capacities are estimated on a twelve months operation basis, which is - at least for hops -higher than reality. The order of product groups is in terms of decreasing total extraction volume. The product groups Chemistry and Environmental Purposes contain both products from natural and artificial origins. Several plants with the same product at one site are counted as one. 

Figure 7.2.19 Continuous-flow 1H NMR spectrum (400 MHz) of caffeine extracted from coffee with supercritical CO2...

In addition to common organic solvents, supercritical fluids (scf s) can be used for a great variety of extraction processes [158 165], Supercritical fluid extraction (SFE), mostly carried out with SC-CO2 as eluant, has many advantages compared to extractions with conventional solvents. The solvent strength of a supercritical fluid can easily be controlled by the pressure and temperature used for the extraction at a constant temperature, extraction at lower pressures will favour less polar analytes, while extraction at higher pressures will favour more polar and higher molar mass analytes. As supercritical fluids such as CO2 and N2O have low critical temperatures (tc = 31 °C and 36 °C, respectively), SFE can be performed at moderate temperatures to extract thermolabile compounds. Typical industrial applications using SC-CO2 include caffeine extraction from coffee beans [158] as well as fat and oil extraction from plant and animal tissues [165]. For some physical properties of supercritical solvents, see Section 3.2. 

Cola is a caffeine-containing seed, or nut, from a tropical tree, the cola tree. In some African countries cola nuts are so valuable they are used as money. The nuts have a bitter, aromatic taste, and people chew them for their stimulating effect. Bottled cola drinks have very little cola nut in them and do not taste like cola nuts at all. Though they do contain caffeine, it is usually synthetic caffeine or caffeine extracted from coffee or tea. These soft drinks are also drugs, and people can become dependent on them, as with coffee. Also, they contain a lot of sugar. 

Because caffeine extraction is an important industrial application of SC CO2 technology, different studies have been recently conducted on solvent recovery by membrane separation. As the molecular weight (MW) (194 g moP ) of caffeine is higher than CO2 (44 g moP ), classical suitable membrane for this application needs to reject caffeine while letting CO2 cross through the membrane. Thus, pure CO2 can be obtained on permeate side and recycled. 

Caffeine extraction Fluorocarbon production Paint removers Rubber... 

Prodolliet et al. (1998) tried to determine the geographic origin of coffee using the isotope ratios (C, N, H) in samples of caffeine extracted from green arabicas and robustas from 16 countries. Neither univariate nor multivariate analysis allowed the determination of the species or of the country of origin. 

H. Kutzhals. Caffeine Extraction," paper presented at the Society of Chemical Industry Food... 

Literature citations of adsorption coupled with supercritical fluid extraction range from the "classical" caffeine extraction with CO2 (1) to recent attempts to separate cholesterol from butter using adsorbent beds of charcoal and silica gel (2). 

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. 

Caffeine, extracted from coffee beans, tea leaves, and the kola nut and used in medicine and beverages. 

A radiometric method utilizing liquid scintillation counting has been developed which can assist in evaluation of the presence and degree of adulteration of plant extraction material with its synthetic counterpart. The basis of the method is the measurement of the decrease in the ambient radiocarbon level of the plant material caused by the addition of petroleum derived synthetic material. Cinnamic aldehyde used for evaluating the quality of cinnarmn, and caffeine extracted from tea and coffee are two products which lend themselves well to this method of analysis. The procedures for sample preparation, liquid scintillation counting and accuracy in evaluating product adulteration are discussed. 

The ability of small molecular fluids under nearcritical conditions to dissolve low-vapour-pressure solid materials was first discovered by Hannay et al. (1). Scheffer and coworkers (2) investigated extensively the solubility of naphthalene in near- and supercritical ethylene. Since then many researchers have started to study the possibilities of supercritical solvents and within the past two decades several research institutes have Investigated and developed the principles and technology of supercritical fluid separations. Commercial application can be found in areas as diverse as spice extraction, monomer purification, coal extraction, nicotine and caffeine extraction, fractionation of (co-) polymers or the extraction of oils from all kinds of natural products. Reviews of most of this work are... 

Tea yields better-quality caffeine than that obtained from coffee. Caffeine from tea is relatively colorless, whereas the caffeine extracted from coffee is highly colored. About 25 mg of caffeine is isolated in either case. Sublimation removes much of the color from the tea and coffee samples. 

Coffee substitute blends and similarly designated products are blends of the above-outlined coffee substitutes, coffee adjuncts and coffee beans. Caffeine-containing coffee substitutes or adjuncts are made by incorporating plant caffeine extracts... 

Caffeine and sodium iodide is an intimate mixture of equal parts of caffeine with sodium iodide. Caffeine is extracted by chloroform in alkaline solution in the usual way. Sodium iodide is determined in the aqueous residues from the caffeine extraction by iodate titration. 

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