Coffee, decaffeinated

The physiological effects of caffeine are not beneficial nor are they tolerated by everyone. Hence, many processes have been developed to remove caffeine ( 0.1%) from coffee. The following process steps are normally used  

In another indirect process, used in the USA, initially all the water-soluble compounds including caffeine are extracted from the green beans. The aqueous extract is decaffeinated with an organic solvent (e. g., dichloroethane), then added back to the green beans and evaporated to dryness with the beans. 

Swollen raw coffee can also be decaffeinated with supercritical CO2 (crit. point 31.06 °C 73.8 bar) at 40-80 °C and a pressure of 200-300 bar. The high vapor pressure of carbon dioxide under normal conditions guarantees a product that is free from solvent residues. Apart from the extraction of caffeine, this process can also be applied in the extraction of odor- and taste-active substances from hops and other plant materials. 

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Decaffeinated coffee products represented 18% of the coffee consumed in 1991 in the United States (31). Decaffeinated coffee was first developed commercially in Europe about 1900. The process as described in a 1908 patent (35) consists of first, moisturizing green coffee to at least 20% to facilitate transport of caffeine through the cell wall, and then contacting the moistened beans with solvents. 

To make an instant decaffeinated coffee product, the decaffeinated roast and ground coffee is extracted in a manner similar to nondecaffeinated coffee. Alternatively, the caffeine from the extract of untreated roasted coffee is removed by using the solvents described previously. 

FIG. 22-22 Schematic diagram of the Kraft process for producing decaffeinated coffee using supercritical carbon dioxide (McHugh and Ktukonis, op. cit.). 

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. 

One of the most widely established processes using SCCO2 is the decaffeination of coffee. Prior to widespread use of this process in the 1980s the preferred extraction solvent was dichloromethane. The potential adverse health effects of chlorinated materials were realized at this time and, although there was no direct evidence of any adverse health effects being caused by any chlorinated residues in decaffeinated coffee there was always the risk, highlighted in some press scare stories. Hence the current processes offer health, environmental and economic advantages. 

Various consumer products have been found to contain trichloroethylene. These include wood stains, varnishes, and finishes lubricants adhesives typewriter correction fluids paint removers and cleaners (Frankenberry et al. 1987). Trichloroethylene use as an inhalation anesthetic, fumigant, and extractant for decaffeinating coffee has been discontinued in the United States (EPA 1985c). 

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... 

Methods for the decaffeination of green coffee beans, mainly with solvents after a steaming, have already been described. Even with the selective adsorption techniques to remove only caffeine, it is unlikely that the full character of the starting beans can be realized in a final decaffeinated beverage the result is that Robusta coffees are generally used to prepare decaffeinated coffee. The cost is kept down and the treatment, anyway, reduces any harsh or bitter flavor that the Robusta coffee may have had. The resulting beverage will be relatively caffeine-free, but Robusta coffee will contribute more soluble carbohydrates, phenols, and volatile fatty acids, and much less of the diterpenes found in Arabica coffees. 

Peter, S. and Brunner, G., Decaffeinating coffee with solvents at high pressure, Ger. Offen. 2,737,794, 1979. (CA90 150500k)... 

Studiengesellschaft Kohle m.b.h, Decaffeinating coffee. Belg 856,955, 1978. (CA89 4866x)... 

Nartowicz, V. B., Buchanan, R. L., Segall, S., Aflatoxin production in regular and decaffeinated coffee beans, J. Food Sci., 44, 446, 1979. (CA90 166747g)... 

Van Rillaer, W., Janssens, G., Beernaert, H., Gas chromatographic determination of residual solvents in decaffeinated coffee, Z. Lebensm. Unters. Forsch., 175, 413,... 

As shown in Table 9, the caffeine content of coffee, tea, and other products can vary dramatically.5 29 33 Caffeine content in a cup of coffee has been reported as 74 mg for percolated coffee and 112 mg for automatic drip coffee, showing substantial differences according to preparation.34 Instant coffee is significantly less at 66 mg and caffeine from decaffeinated coffee is negligible (1 to 3 mg caffeine). 

The U.S. is responsible for consuming the most coffee overall in the world in 1991, it was estimated that each person consumed nearly 27 gallons (101.4 liters) of coffee.10 Decaffeinated coffee is consumed less frequently in the U.S., at levels of 24% in 1987 to 15% in 1993.10 Table 11 shows that the U.S. by far consumed the most coffee in weight than any other nation in the world, nearly double that of Germany as the second highest consumer.38 Estimates for the U.S. up to the early 1990s did not show a great increase in total consumption, but rather a stabilization that is consistent with coffee trade to and from the U.S. 

Superko, H., Bortz, W., Williams, P., Albers, J. and Wood, P., Caffeinated and decaffeinated coffee effects on plasma lipoprotein cholestrol, apolipoprotiens and lipase activity A controlled, randomized trial. American Journal of Clinical Nutrition 54, 599-605, 1991. 

Hofer, I., Battig, K., Psychophysiological effects of switching to caffeine tablets or decaffeinated coffee under field conditions. Special Issue Caffeine research. Pharmacopsychoecologia 7(2), 169-177, 1994. 

The failure to find an effect in the American trial above was confirmed in a study conducted in the Netherlands, which also used paper-filtered, drip-brewed coffee.14 In that 12-week experiment, 23 women and 22 men who habitually drank 4 to 6 cups of coffee per day were assigned to consume 5 cups/day of either caffeinated (417.5 mg caffeine/day) or decaffeinated coffee (15.5 mg caffeine/day) for six weeks, and then switch for another six weeks. The blend of coffee beans was 71% Arabica and 29% Robusta for the caffeinated coffee, and 58% Arabica and 42% Robusta for the decaffeinated coffee. Lipid values at the end of both six-week study periods were almost identical. Total cholesterol was 5.47 vs. 5.48 mmol/ L (212 vs. 212 mg/dL), LDL-C was 3.41 vs. 3.40 mmol/L (132 vs. 131 mg/ dL), HDL-C was 1.52 vs. 1.52 mmol/L (59 vs. 59 mg/dL), and TG were 1.17 vs. 1.20 mmol/L (104 vs. 106 mg/dL) for the caffeinated vs decaffeinated coffee periods, respectively. Further, a small study of 12 Finnish men also failed to find an effect of caffeinated coffee on serum cholesterol levels.15 However, the study period was only three weeks which may have been insufficient. 

Massey and Opryszek9 elaborated further by showing that habitual caffeine consumption induced chronic hypercalcuria in young women (mean 24 years) after an oral caffeine challenge where they were fed either 300 mg of caffeine tablets per day or 6 mg caffeine per kilogram lean body mass (LBM) per day (range 274 to 325 mg/caffeine) mixed with decaffeinated coffee or tea when compared to a week of abstinence. Ad-... 

Oral caffeine loads added to decaffeinated coffee or tea Self report of daily intake of cups of coffee... 

Raaska, K., Raitasuo, V., Laitila, J. Neuvonen, P. J. (2004). Effect of caffeine-containing versus decaffeinated coffee on serum clozapine concentrations in hospitalised patients. Pharmacol. Toxicol, 94, 13-18. 

Although placebo effects are generally referred to as nonspecific, there is also a sense in which they are very specific. The effect of the placebo is specific to the beliefs that people have about the substance they are ingesting. Placebo morphine, for example, reduces pain, whereas placebo antidepressants reduce depression. Even the side effects that people report when given a placebo tend to be the same side effects that are produced by the real drug.12 In other words, the effect of a placebo is specific to the effect that the person expects it to have. When given placebo stimulants like decaffeinated coffee (presented as regular coffee), people feel more alert, and their heart rate and... 

We continue our theme of coffee . Most coffees contain a large amount of the heterocyclic stimulant caffeine (I). Some people prefer to decrease the amounts of caffeine they ingest for health reasons, or they simply do not like to consume it at all, and they ask for decaffeinated coffee instead. 

Secondly, solid CO2 is relatively cheap. Finally, after caffeine removal, any occluded CO2 will vaporize from the coffee without the need to heat it or employ expensive vacuum technology. Again, we retain the volatile essential oils of the coffee. Even if some CO2 were to persist within the coffee granules, it is chemically inert, has no taste and would be released rapidly as soon as boiling water was added to the solid, decaffeinated coffee. 

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