Bean, coffee

Caffeine. About 3% by weight of the roasted coffee bean is caffeine (16). The second U.S. Department of Agriculture world coffee crop estimate for 1988—1989 was 4.24 x 10 kg (93.3 million 100-lb bags) (102). World coffee consumption was predicted to rise in the foreseeable future at the rate of 1—2% per year and thus the total amount of caffeine and related alkaloids ingested from this source can also be expected to increase. Caffeine and related bases (eg, theophylline) are also found in various teas but, because most of the major producers (India, China, etc) export relatively Htfle of thek crops and keep most for domestic consumption, accurate figures on year-to-year production are more difficult to obtain. Nevertheless, these crops are of significant economic import (103). 

Highly pure / -hexane is used to extract oils from oilseeds such as soybeans, peanuts, sunflower seed, cottonseed, and rapeseed. There has been some use of hydrocarbons and hydrocarbon-derived solvents such as methylene chloride to extract caffein from coffee beans, though this use is rapidly being supplanted by supercritical water and/or carbon dioxide, which are natural and therefore more acceptable to the pubHc. 

Lactisole [13794-15-5] the sodium salt of racemic 2(4-methoxyphenoxy)propionic acid, is a sweet-taste inhibitor marketed by Domino Sugar. It was affirmed as a GRAS flavor (FEMA no. 3773). At a concentration of 100 to 150 ppm, lactisole strongly reduces or eliminates the sweet taste of a 10% sugar solution. This inhibition appears to be receptor-related because lactisole also inhibits the sweet taste of aspartame. The 5 -( —)-enantiomer [4276-74-8] (38), isolated from roasted coffee beans, is the active isomer the i -(+)-enantiomer is inert (127). 

In the wet method, as practiced in Colombia, freshly picked ripe coffee cherries are fed into a tank for initial washing. Stones and other foreign material are removed. The cherries are then transferred to depulping machines which remove the outer skin and most of the pulp. However, some pulp mucilage clings to the parchment shells that encase the coffee beans. Fermentation tanks, usually containing water, remove the last portions of the pulp. Fermentation may last from twelve hours to several days. Because prolonged fermentation may cause development of undesirable flavors and odors in the beans, some operators use enzymes to accelerate the process. 

A. G. W. Bradbury and D. J. HaUiday, "Polysaccharides in Green Coffee Beans," Proceedings of the 12th Colloquium ofyiSIC, Montreux, 1987, pp. 265-269. 

Green coffee bean dust Coffee processing and food industries... 

Coffee Roasting Heavy Oils from coffee beans... 

Atractyligenin and its sulfated glucoside (actractyloside) are toxins which block the transport of ADP into mitochondria and which occur in the coffee bean. Atractyligenin was synthesized following a multistrategic retrosynthetic plan in which the disconnection of ring B was a major objective. Novel stereocontrolled processes were employed for the critical cyclization to form the tetracarbocyclic network and for introduction of the carboxylic substituent. 

The synthesis of cafestol, an antiinflammatory agent which occurs in coffee beans along with related diterpenoids such as actractyloside and kahweol, was accomplished by the same strategic approach which was applied to its companion atractyligenin. 

A cup of brewed coffee is made with about 9.0 g of ground coffee beans. If a student brews three cups of gourmet coffee a day, how much does the student spend on a year s supply of gourmet coffee that sells at 8.99/lb ... 

Caffeine occurs in tea leaves, coffee beans, and cola nuts. Morphine is obtained from unripe opium poppy seed pods. Coniine, extracted from hemlock, is the alkaloid that killed Socrates. Fie was sentenced to death because of unconventional teaching methods teacher evaluations had teeth in them in ancient Greece. 

The dense fluid that exists above the critical temperature and pressure of a substance is called a supercritical fluid. It may be so dense that, although it is formally a gas, it is as dense as a liquid phase and can act as a solvent for liquids and solids. Supercritical carbon dioxide, for instance, can dissolve organic compounds. It is used to remove caffeine from coffee beans, to separate drugs from biological fluids for later analysis, and to extract perfumes from flowers and phytochemicals from herbs. The use of supercritical carbon dioxide avoids contamination with potentially harmful solvents and allows rapid extraction on account of the high mobility of the molecules through the fluid. Supercritical hydrocarbons are used to dissolve coal and separate it from ash, and they have been proposed for extracting oil from oil-rich tar sands. 

In some cases, the solids themselves are subjected to extraction by a solvent. For example, in one process used to decaffeinate coffee, the coffee beans are mixed with activated charcoal and a high-pressure stream of supercritical carbon dioxide (carbon dioxide at high pressure and above its critical temperature) is passed over them at approximately 90°C. A supercritical solvent is a highly mobile fluid with a very low viscosity. The carbon dioxide removes the soluble caffeine preferentially without extracting the flavoring agents and evaporates without leaving a harmful residue. 

Group (c), a-D-mannosidase from jack beans and from almonds, and a-D-galactosidase from coffee beans, showed no inactivation. The results with these enzymes can possibly be explained by the formation of a (weak) non-covalent complex in which glycosylation is too slow to cause inactivation within the time period of measurements, or, less likely, rapid hydrolysis of the glycosyl-enzyme intermediate. 

The basic process outline is depicted in Figure 5.2 moist un-roasted coffee beans and CO2 are fed counter-currently into the extractor under supercritical conditions. Caffeine is selectively extracted into the CO2 and this stream is led to a water-wash column to remove caffeine at a reduced pressure, the CO2 being recycled back to the extraction column. Extraction of the caffeine into water is necessary to avoid dropping the CO2 pressure too low, since compression is energy-intensive. There is now the problem of separating the caffeine (which is used in soft drinks and pharmaceu-... 

How would you describe the differences between a cup of coffee and a cup of hot water What probably come to mind are the aroma, the dark color, and the taste of a good cup of coffee. Coffee s action as a stimulant is another obvious difference. These properties come from the chemical compounds that hot water dissolves from ground coffee beans. These compounds are molecules constructed from different atoms bound together in veiy specific arrangements. The molecule that makes coffee a stimulant is caffeine. Our background photo is a magnification of crystals of pure caffeine, and the inset is a ball-and-stick model of this molecule. 

Decaffeination of Coffee and Tea This application is driven by the environmental acceptability and nontoxicity of CO2 as well as by the ability to tailor the extraction with the adjustable solvent strength. It has been practiced industrially for more than two decades. Caffeine may be extracted from green coffee beans, and the aroma is developed later by roasting. Various methods have been proposed for recovery of the caffeine, including washing with water and adsorption. 

Caffeine was extracted from ficw varieties of roasted coffee beans and was determined in parallel by (1) measurement of spot area after thin layer chromatography on silica gel GF plates (development with chloroform/ cyclohexane/glacial acetic acid, 8 2 1, visualization in UV light), and (2) Kjeldahl N determination. Caffeine contents by (1) and (2), respectively, in the five varieties analyzed were (percent in DM) Santos lave 0, 1.10, and 1.12 Java Robusta 3, 1.19, and 1.22 Camerun Robusta 2, 1.16, and 1.19 Mocca 2, 1.21, and 1.26 Guatemala 0, 1.18, and 1.20. (1) is considered slightly less accurate than (2) but rather easier and more rapid.21... 

A method for determining the caffeine content of regular and decaffinated green and roasted coffee beans and of regular and decaffeinated coffee extract powders, using HPLC, is specified in a British Standard Instruction.34 Caffeine is extracted from the sample with water at 90°C in the presence of magnesium oxide. The mixture is filtered and an aliquot purified on a silica microcolumn modified with phenyl groups. The caffeine content is then determined by HPLC with UV detection.35... 

Washuettl, J., Bancher, E., and Riederer, P., A new thin-layer chromatographic method for determination of caffeine in roasted coffee beans, Zeitschrift fuer Lebensmitteluntersuchung und Forschung, 143,253,1970. 

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