Caffeine trends

Zougagh, M., Valcarcel, M., and Rios, A., Automatic selective determination of caffeine in coffee and tea samples by using a supported liquid membrane-modified piezoelectric flow sensor with molecularly imprinted polymer. Trends Anal. Chem., 23, 399, 2004. 

The desirability of partial shade on tea estates has been a controversial subject. Desirable effects include temperature moderation at the leaf surface, which decreases low-humidity stress, and an increased yield of chlorophyll, amino acid, and caffeine production. The undesirable effects include decreased photosynthetic activity and competition for water and solid nutrients by the shade tree employed. In general, the trend has been toward the elimination of shade in most black-tea growing areas. Green tea products benefit from the additional chlorophyll and amino acid pro-... 

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. 

Health concerns about the effects of coffee are also an important consideration in coffee drinking trends. While many health issues have not been systematically and thoroughly evaluated, these concerns have undoubtedly contributed to consumption patterns. However, the most significant changes in coffee consumption occurred prior to scientific research and knowledge of health effects due to caffeine exposure. 

Gupta BS and Gupta U (1999). Caffeine and Behaviour Current Views and Research Trends. CRC Press, London. 

There is a recent trend towards simultaneous CE separations of several classes of food additives. This has so far been applied to soft drinks and preserved fruits, but could also be used for other food products. An MEKC method was published (Lin et al., 2000) for simultaneous separation of intense sweeteners (dulcin, aspartame, saccharin and acesulfame K) and some preservatives (sorbic and benzoic acids, sodium dehydroacetate, methyl-, ethyl-, propyl- and isopropyl- p-hydroxybenzoates) in preserved fruits. Ion pair extraction and SPE cleanup were used prior to CE analysis. The average recovery of these various additives was 90% with good within-laboratory reproducibility of results. Another procedure was described by Frazier et al. (2000b) for separation of intense sweeteners, preservatives and colours as well as caffeine and caramel in soft drinks. Using the MEKC mode, separation was obtained in 15 min. The aqueous phase was 20 mM carbonate buffer at pH 9.5 and the micellar phase was 62 mM sodium dodecyl sulphate. A diode array detector was used for quantification in the range 190-600 nm, and limits of quantification of 0.01 mg/1 per analyte were reported. The authors observed that their procedure requires further validation for quantitative analysis. 

Caffeine experts cite the widespread use of coffee, cola drinks, water, and other drinks spiked with caffeine as making it the most widely used mind drug. After a period in which clear and no-caffeine drinks were popular, the trend toward caffeinated soft drinks and coffee is back. Many teens socialize at coffee shops instead of the soda fountains that attracted their parents. 

ASHIHARA, H., CROZIER, A., Caffeine a well known but little mentioned compound in plant science., Trends Plant Sci., 2001,6,407-413. 

Crystallinity was checked by comparing X-Rays diffraction patterns of the products and feed. Measurements were performed directly on the material collected on the slide held in the crystallization unit. For caffeine, the filament structure gives only a weak major peak and a broad band between the 20 values of 18 and 32, indicating some disorder compared to the crude sample. Needles morphology does not provide necessarily the complete x-rays pattern. No correlation was found between experimental conditions and the lack of minor peaks. Furthermore, when the slide was overloaded with material collected from the beaker sides, most of the peaks were detected. So the lack of minor peaks may be most likely due to insufficient quantity of material but can also represent a partial loss of crystallinity for a specific material. Similar trends were... 

As with DNA aptamers, there is a trend towards applying RNA aptamers to a particular application. Allosteric ribozyme sensors have been developed which are specific for caffeine and aspartame. " Using a fluorescence-based assay, caffeine or aspartame may be detected in solution over a 0.5 5mM concentration range. Aptamers designed to malachite green (151) or other triphenylmethane dyes have been developed that enhance the fluorescence of the dye up to 2300-fold. " A further fluorescence-based assay has been... 

In summary, caffeine is consumed worldwide by people of all races and social cla.sses. Estimates arc that about 90% of the world s population regularly consumes products that contain caffeine, with coffee, tea, and soft drinks the most common sources (James, 1991). Trends in recent years in overall caffeine u.se arc difficult to spccift because of the measurement problems we referred to earlier. Nevertheless, there is no question that caffeine is the world s most preferred drug. 

Figure 33-1 5 Typical separation by MECC. (a) Some test compounds 1 = methanol, 2 = resorcinol, 3 = phenol, 4 = p-nitroaniline, 5 = nitrobenzene, 6 = toluene, 7 = 2-naphthol, 8 = Sudan III capillary, 50-p.m inside diameter, 500 mm to the detector applied voltage, ca. 15 kV detection UV absorption at 210 nm. (b) Analysis of a cold medicine 1 = acetaminophen, 2 = caffeine, 3 = sulpyrine, 4 = naproxen, 5 = guaiphenesin, 10 = noscapine, 11 = chloropheniramine and tipepidine applied voltage, 20 kV capillary, as in (a) detection UV absorption at 220 nm. (From S. Terabe, Trends Anal. Client., 1989,8, 129.)...

For all that, the history of coffee has not come to an end. People liked the social atmosphere of coffee drinking but did not want the possible effect of caffeine, hence the decaffeination process, or of some acids, hence the steam-treatment. For others, making coffee from the roasted beans was too much trouble, hence the preparation of soluble coffees, decaffeinated or not. All these treatments alter the content, and therefore the taste of the beverage. There is now a trend to new products (iced coffee, iced cappuccino for example). There are also gourmet people who buy specialty roasted coffee and increase the side-market for coffee-pots or espresso makers by brewing coffee according to their taste. 

None of the widely quoted statistics embrace all those individuals dependent on drugs and medicaments, but always only those who attract attention because of crime, their lifestyle, or their social environment. In the case of benzodiazepines, appetite-suppressants and combinations of analgesics with caffeine, the low-dose dependence of the patient is often associated with social conditions, so that the problem is often seen in the context of the particular decade in which the abuse occurs. The same is true of the experimental drug-taker who discontinues his or her consumption after a short time and is not noticed. For this reason, exact national statistics on consumption behavior are difficult to obtain. Moreover, it is possible to detect trends, e.g. the appearance of new dependence phenomena, patterns of abuse, drug combinations or methods of application, and the analyst must arrange his work accordingly. 

Friedman J, Waller GR (1985) Allelopathy and autotoxicity. Trend Biochem Sci 10 47-50 Ransom F (1912) The effects of caffeine upon the germination and growth of seeds. Biochem... 

Kesavan, P. C., 1990, Differential modification of oxygen-dependent and independent component of radiation mutagenesis by caffeine, in Recent Trends in Radiobiological Research (P. Uma Devi, ed.), pp. 141-157, Scientific Publishers, Jodhpur. 

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