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PubMed2004

Coffee, decaffeinated coffee, tea and cancer of the colon and rectum: a review of epidemiological studies, 1990-2003.

The literature from 1990 to 2003 on the relation between coffee, decaffeinated coffee, tea and colorectal cancer risk has been reviewed. For the relation with coffee, three cohort (517 total cases) and nine case-control studies (7555 cases) analysed colon cancer; three cohort (307 cases) and four case-control studies (2704 cases) rectal cancer; six case-control studies (854 cases) colorectal cancer. For colon cancer most case-control studies found risk estimates below unity; the results are less clear for cohort studies. No relation emerged for rectal cancer. A meta-analysis, including five cohort and twelve case-control studies, reported a pooled relative risk of 0.76 (significant). Any methodological artefact is unlikely to account for the consistent inverse association in different countries and settings. Plausible biological explanations include coffee-related reductions of cholesterol, bile acids and neutral sterol secretion in the colon; antimutagenic properties of selected coffee components; increased colonic motility. Decaffeinated coffee was not related to either colon or rectal cancer in three case-control studies. No overall association between tea and either colon or rectal cancer risk emerged in seven cohort (1756 total cases of colon, 759 of rectal and 60 of colorectal cancer) and 12 case-control studies (8058 cases of colon, 4865 of rectal, 604 of colorectal cancer).

Antioxidants↗

PubMed2006

Determination of acrylamide in coffee and coffee products by GC-MS using an improved SPE clean-up.

An improved gas chromatography-mass spectrometry (GC-MS) method to determine acrylamide (AA) in coffee and coffee products was developed. The method was based on two main purification steps: the first with ethanol and Carrez solutions in order to precipitate polysaccharides and proteins, respectively; and the second with a layered solid-phase extraction (SPE) column which proved to be efficient in the elimination of the main chromatographic interferences. The method is applicable to a wide range of coffee products. Twenty-six samples of different coffee products were analysed. The levels of AA were in the range 11.4-36.2 microg l-1 for 'espresso coffee' and 200.8-229.4 microg l-1 for coffee blends with cereals. The results indicate that the presence of cereals significantly increased the levels of AA.

Acrylamide↗

PubMed1976

[The effect of coffee and coffee components on the stomach muscle].

The isolated stomach muscle strip preparation works well when given pure compounds which are stable and non-toxic. When complex test mixtures such as coffee are used, however, the results are more difficult to interpret. This is probably due to non-specific effects of such mixtures, e.g. induction of changes in organ bath pH, etc. In spite of the above remark, differences in the effects of decaffeinated and normal instant coffees were clearly seen. The so-called "wholesome" coffees gave results identical to those obtained with normal instant coffee. In general, coffee induced muscle contraction followed by relaxation. Choline (possibly together with potassium) would appear to be responsible for the contractions observed, and caffeine for the relaxation.

Animals↗

PubMed1978

The effects of de-caffeinated coffee versus whole coffee on hyperactive children.

The effects of whole coffee and de-caffeinated coffee on hyperactive children were compared, using a double-blind crossover design. Reactions were assessed by tests of concentration, digit recall, visuo-motor co-ordination, and parents' and teachers' rating scales. Whole coffee was associated with a significant improvement on all measures when compared with de-caffeinated coffee. The results suggest that whole coffee as part of the normal diet may be a useful first step in the treatment of hyperactive children.

Attention↗

PubMed2004

Volatile composition of coffee berries at different stages of ripeness and their possible attraction to the coffee berry borer Hypothenemus hampei (Coleoptera: Curculionidae).

The analysis of volatile emissions of coffee berries in different physiological states of ripeness was performed using dynamic headspace and gas chromatography/mass spectrometry analysis for Coffea arabica, var. Colombia. The composition of the volatiles emitted by coffee berries is dominated by very high levels of alcohols, mainly ethanol, in all stages of ripeness in comparison with other compounds. Overripe coffee berries have high volatile emissions and show a composition dominated mainly by esters followed by alcohols, ketones, and aldehydes. The lowest level compounds were monoterpenes. 2-Methyl furan was detected in various ripening stages; this compound has not been previously reported as a coffee berry volatile. The presence of ethanol and other alcohols in the volatile composition might explain the effectiveness of using traps with mixed alcohols for detection and capture of coffee berry borers.

Alcohols↗

PubMed2000

Genotoxicity of instant coffee and of some phenolic compounds present in coffee upon nitrosation.

Instant coffee exhibits genotoxic activity upon nitrosation at acidic pH values in the Ames tester strain TA100. Using adsorption chromatography (Amberlit XAD-2) it was observed that the major fraction of molecules responsible for the genotoxic activity upon nitrosation was not retained on this resin, suggesting that the polar molecules present in instant coffee could be responsible for the genotoxicity observed upon nitrosation. Some phenolic molecules present in instant coffee (catechol, caffeic acid, and chlorogenic acid) were also genotoxic upon nitrosation under the same experimental conditions. The concentrations of nitrosatable phenolic compounds in the studied coffee were determined by HPLC and their contributions to the total genotoxicity observed were studied. The results obtained suggest that besides phenolic compounds other molecules were also involved in the genotoxicity of this beverage upon nitrosation. Teratogenesis Carcinog. Mutagen. 20:241-249, 2000.

Adsorption↗

PubMed2006

Coffee inhibits the reactivation of glucocorticoids by 11beta-hydroxysteroid dehydrogenase type 1: a glucocorticoid connection in the anti-diabetic action of coffee?

Recent epidemiological studies demonstrated a beneficial effect of coffee consumption for the prevention of type 2 diabetes, however, the underlying mechanisms remained unknown. We demonstrate that coffee extract, corresponding to an Italian Espresso, inhibits recombinant and endogenous 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) activity. The inhibitory component is heat-stable with considerable polarity. Coffee extract blocked 11beta-HSD1-dependent cortisol formation, prevented the subsequent nuclear translocation of the glucocorticoid receptor and abolished glucocorticoid-induced expression of the key gluconeogenic enzyme phosphoenolpyruvate carboxykinase. We suggest that at least part of the anti-diabetic effects of coffee consumption is due to inhibition of 11beta-HSD1-dependent glucocorticoid reactivation.

11-beta-Hydroxysteroid Dehydrogenase Type 1↗

PubMed2005

Study of acrylamide in coffee using an improved liquid chromatography mass spectrometry method: Investigation of colour changes and acrylamide formation in coffee during roasting.

An improved analytical method for the determination of acrylamide in coffee is described using liquid chromatography coupled to mass spectrometric detection (LC-MS). A variety of instant, ground and laboratory roasted coffee samples were analysed using this method. The sample preparation entails extraction of acrylamide with methanol, purification with Carrez I and II solutions, evaporation and solvent change to water, and clean-up with an Oasis HLB solid-phase extraction (SPE) cartridge. The chromatographic conditions allowed separation of acrylamide and the remaining matrix co-extractives with accurate and precise quantification of acrylamide during MS detection in SIM mode. Recoveries for the spiking levels of 50, 100, 250 and 500?microg/kg ranged between 99 and 100% with relative standard deviations of less than 2%. The effects of roasting on the formation of acrylamide and colour development were also investigated at 150, 200 and 225 degrees C. Change in the CIE (Commission Internationale de l'Eclairage) a* colour value was found to show a good correlation with the change in acrylamide. CIE a* and acrylamide data was fitted to a non-linear logarithmic function for the estimation of acrylamide level in coffee. Measured acrylamide levels in commercial roasted coffees compared well with the predicted acrylamide levels from the CIE a* values.

Acrylamide↗

PubMed1982

Hydride generation and condensation flame atomic absorption spectroscopic determination of antimony in raw coffee beans and processed coffee.

A method was developed for determining Sb at nanogram per gram levels in raw coffee beans and processed coffee. The procedure uses either total acid digestion or extraction with 6M HCl followed by hydride generation/condensation with subsequent revolatilization of stibine (SbH3) and detection by flame atomic absorption spectroscopy. The lowest quantifiable level, based on a 2 g (dry weight) sample, is 2 ng Sb/g. The results of recoveries on spiked samples, precision studies on composited coffee samples, and the analysis of National Bureau of Standards Standard Reference Materials demonstrate the reliability and accuracy of the procedure. Sb concentrations in coffee samples were verified by neutron activation analysis and inductively coupled plasma atomic emission spectroscopy. Advantages of the method compared with the AOAC colorimetric procedure and hydride generation without condensation are discussed.

Antimony↗

PubMedDate not supplied

Adulteration of soluble coffee with coffee husks and parchments.

Commercial soluble coffee can be adulterated with coffee husks or parchments. Xylose is a good tracer for this type of mispractice. The analysis of total xylose in a wide selection of green beans and the assessment of its fate during processing allowed the derivation of a maximum total xylose limit of 0.40%, above which a soluble coffee should be considered as adulterated. Out of the 700 commercial soluble coffees analyzed, 81 exhibited a total xylose level above this limit. Of the samples with total xylose level lower than the limit, 99% displayed concentrations in free mannitol and total glucose below 0.30 and 2.10%, respectively.

Chromatography, Ion Exchange↗

PubMed1994

Trigonelline in coffee. II. Content of green, roasted and instant coffee.

The results of several determinations of trigonelline in green, roasted and instant coffees are reported. The values in normal coffee species and degrees of roast are in agreement with most literature values. In Coffea dewevrei var. excelsa and C. stenophylla lower values were found than reported in the only other publication. The differences from steamed samples were minimal. Fast roasting may result in higher values with the same organic roasting loss, but this was not observed in commercial blends. During industrial extraction of roasted coffee, trigonelline is not completely extracted. The percentage depends on the extraction yield.

Alkaloids↗

PubMed1996

Analysis of free amino acids in green coffee beans. II. Changes of the amino acid content in arabica coffees in connection with post-harvest model treatment.

To investigate amino acid changes in green coffee beans in the post-harvest period, amino acid concentrations were determined in green beans and after modelled drying, fermentation and storage. After the drying at alternating temperatures up to maximally 40 degrees C, considerable changes in the concentrations of individual amino acids were identified. At the beginning of the storage period, significant changes in concentration were found to a minor extent. Under the condition of drying, it was mainly the concentration of glutamic acid that changed considerably. There was an increase in all the samples by 500 mg/kg dry matter on average, which corresponds to an increase of about 50% of the original value. In contrast, the concentration of aspartic acid in most of the samples decreased clearly due to drying. For the predominant part of the coffee samples, there was a significant increase in the hydrophobic amino acids Val, Phe, Ile and Leu. Changes of the quantities of other amino acids were non-uniform and only insignificant. Constant drying at 80 degrees C for most of the amino acids brought about only minor concentration changes compared to those values obtained at 40 degrees C. Modelled fermentation had no significant effect on the concentrations of the individual amino acids. After a 4-week storage of dried beans, amino acid concentrations did not change further. It is very possible that different post-harvest treatment parameters may influence the amount of aroma precursor compounds in the coffee beans.

Amino Acids↗

PubMed2001

Model studies on the influence of coffee melanoidins on flavor volatiles of coffee beverages.

Addition of the total melanoidin fraction isolated by water extraction from medium-roasted coffee powder to a model solution containing a set of 25 aroma compounds mimicking the aroma of a coffee brew reduced, in particular, the intensity of the roasty, sulfury aroma quality. Model studies performed by static headspace analysis revealed that especially three well-known coffee odorants, that is, 2-furfurylthiol (FFT), 3-methyl-2-butene-1-thiol, and 3-mercapto-3-methylbutyl formate, were significantly reduced in the headspace above an aqueous model solution when melanoidins were added. In particular, the low molecular weight melanoidins (1500-3000 Da) led to the most significant decrease in FFT. In contrast, for example, aldehydes remained unaffected by melanoidin addition.

Chromatography, Gas↗

PubMed2003

Coffee ringspot virus vectored by Brevipalpus phoenicis (Acari: Tenuipalpidae) in coffee.

Coffee ringspot is characterized by conspicuous ringspot symptoms on leaves, berries, and less frequently on twigs. It is caused by coffee ringspot virus (CoRSV), a short, bacilliform virus (40 nm x 100-110 nm). The virus is not seed borne and is transmitted by Brevipalpus phoenicis (Geijskes). Transovarial transmission within the mite does not occur. CoRSV has been mechanically transmitted to Chenopodium amaranticolor Coste and Reynaud, C. quinoa Wildenow, Beta vulgaris L., and Alternanthera tenella Colla resulting in local lesions. Systemic infection within both C. amaranticolor and C. quinoa occurs. Virions are found in the nucleus or cytoplasm of infected cells, commonly associated with membranes. Occasionally, membrane bounded particles are found within the cisternae of the endoplasmic reticulum. A characteristic electron lucent, nuclear inclusion is commonly found in many infected cells. These cytopathic effects place CoRSV among the nuclear type of Brevipalpus-borne viruses. The disease has been reported in several Brazilian states (São Paulo, Paraná, Minas Gerais, and Federal District) and recently found in Costa Rica. A similar disease is known in the Philippines, but no information exists about its relationship to CoRSV. Coffee ringspot had no economical significance until recently when a large scale infection was reported in Minas Gerais that resulted in yield loss.

Animals↗

PubMed1995

A placebo-controlled parallel study of the effect of two types of coffee oil on serum lipids and transaminases: identification of chemical substances involved in the cholesterol-raising effect of coffee.

In a randomized double-blind parallel study in 36 subjects the effect on serum cholesterol of a daily dose of 2 g lipid extracted from green Arabica and Robusta coffee beans was studied. Arabica oil elevated serum total cholesterol by 1.1 mmol/L (95% CI for the difference from placebo: 0.41, 1.73 mmol/L); the effect of robusta oil (+0.5 mmol/L) was not statistically significant (95% CI: -0.01, 0.92 mmol/L). Arabica oil also raised plasma triglycerides by 0.8 mmol/L (95% CI: 0.26, 1.25 mmol/L). The effect of robusta oil on triglycerides was +0.14 mmol/L and not significant (95% CI: -0.26, 0.42 mmol/L). In the 12 subjects taking arabica oil an average serum alanine amino-transferase elevation of 18 U/L (95% CI: 9.4, 28.4 U/L) was observed. Because only arabica oil contains kahweol and arabica coffee contains more cafestol than does robusta oil, this is further evidence for the role of diterpenes in the rise of serum cholesterol and alanine aminotransferase after consumption of boiled coffee.

Administration, Oral↗

PubMed2006

Coffee: good, bad, or just fun? A critical review of coffee's effects on liver enzymes.

Coffee consumption is a regular part of daily life throughout the world. Research into the effects of coffee on human health is ongoing, but a recent study suggests that coffee and caffeine consumption can reduce the risk of elevated alanine aminotransferase activity in individuals at high risk for liver disease. This review will analyze the results of that study in light of the current literature.

Alanine Transaminase↗

PubMed2000

[Massive multiplication of coffee (Coffee arabica L. cv. Catimor) through embryogenic cell suspension culture].

Cell suspensions offer several advantages as a system for massive propagation because of the high rates of multiplication, the higher homogeneity in the culture conditions and the possibility of automatization. In this study, different experimental conditions were analyzed to establish embryogenic cell suspension cultures of coffee. The best conditions to establish the embryogenic cell suspension cultures of coffee were as follows: coffee leaf sections were cultivated during 12 weeks (Stage I) in a solid medium with the Murashige and Skoog salts, 2 mg/l kinetin and 0.5 mg/l 2,4-dichlorophenoxiacetic acid (medium 1). Under these conditions the explants formed a callus tissue that was transferred to a liquid medium containing 5 mg/l of 6-benzylamlno-purine (medium 2). After 12 days in a shaking liquid medium (Stage II), the cultures were sieved and were maintained In the same media, which was renewed every eight days (Stage III). This method yielded 1884 embryos in 50 ml; placing the embryos under conditions for germination yielded plantlets of normal appearance.

Cloning, Organism↗

PubMedDate not supplied

A survey of homopteran species (Auchenorrhyncha) from coffee shrubs and poró and laurel trees in shaded coffee plantations, in Turrialba, Costa Rica.

A survey of homopteran species (Auchenorryncha) was conducted in coffee plantations with no shade (C), and in those with shade of either poró (Erythrina poeppigiana) (CP) or poró plus laurel (Cordia alliodora) (CPL), in Turrialba, Costa Rica. A total of 130 species in ten families were collected, dominated by Cicadellidae (82 species). Species richness was highest in the CP system (88), followed by CPL (74) and C systems (60). Five most common species for all systems were Fusigonalia lativittata, Hebralebra nicaraguensis, Neocoelidia sp., Oliarus sp. and Clastoptera sp. Diversification of the coffee agroecosystem favors some species while limiting others, and have no effect on the majority of species. Thus, only F. lativittata, Neocoelidia sp. and Scaphytopius ca. latidens were well represented in all systems, but were more abundant in coffee shrubs. Additionally, the following were the dominant species in each system: Graphocephala sp. 1 (C), F. lativittata (CP) and H. nicaraguensis (CPL). Four species abundant on laurel trees, including H. nicaraguensis, appeared almost exclusively on these tree species. Species similarity was highest on the CP and CPL systems (51% of the species in common), followed by the C and CP (39%) and the C and CPL systems (38%). These findings show that even disturbed systems can harbor many insect species, so that they deserve attention from conservation advocates and biologists.

Animals↗