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PubMed2006

Investigation of sample treatment steps for the analysis of polycyclic aromatic hydrocarbons in ground coffee.

Sample treatment procedures were tested for the determination of polycyclic aromatic hydrocarbons (PAHs) in ground coffee. Pressurized liquid extraction (PLE), under different conditions, was combined with several cleanup methods, namely in situ purification, C18-silica solid-phase extraction (SPE), silica SPE, acid digestion, and alkaline saponification. Soxhlet extraction and direct alkaline saponification were also tested. Best results were obtained using PLE with hexane/acetone 50:50 (v/v) under 150 degrees C. Alkaline saponification followed by cyclohexane extraction and silica SPE was required to eliminate interferent compounds. Finally, 11 PAHs could be quantified in ground coffee with limits of detection in the range of 0.11-0.18 microg kg(-1). Application to ground Arabica coffee lots from Colombia revealed the presence of several PAHs, giving an overall toxicity equivalence in the range of 0.16-0.87 microg kg(-1). PAH identification was performed using both high-performance liquid chromatography-diode array detection and gas chromatography coupled to mass spectrometry.

Chromatography, High Pressure Liquid↗
PubMed2006

High molecular weight melanoidins from coffee brew.

The composition of high molecular weight (HMw) coffee melanoidin populations, obtained after ethanol precipitation, was studied. The specific extinction coefficient (K(mix)) at 280, 325, 405 nm, sugar composition, phenolic group content, nitrogen content, amino acid composition, and non-protein nitrogen (NPN) content were investigated. Results show that most HMw coffee melanoidins are soluble at high ethanol concentrations. The amino acid composition of the HMw fractions was similar, while 17% (w/w) of the nitrogen was NPN, probably originating from degraded amino acids/proteins and now part of melanoidins. A strong correlation between the melanoidin content, the NPN, and protein content was found. It was concluded that proteins are incorporated into the melanoidins and that the degree of chemical modification, for example, by phenolic groups, determines the solubility of melanoidins in ethanol. Although the existence of covalent interaction between melanoidins and polysaccharides were not proven in this study, the findings suggest that especially arabinogalactan is likely involved in melanoidin formation. Finally, phenolic groups were present in the HMw fraction of coffee, and a correlation was found with the melanoidin concentration.

Amino Acids↗
PubMed1999

Rapid analysis of cholesterol-elevating compounds in coffee brews by off-line high-performance liquid chromatography/high-resolution gas chromatography.

A new method is proposed to analyze the cholesterol-elevating cafestol and kahweol which allows their rapid and reliable determination in different coffee brews. The method involves the preseparation of the sample by high-performance liquid chromatography, the collection of the selected fraction, and its subsequent analysis by high-resolution gas chromatography using a programmed temperature vaporizer operated in the split mode as sampling system. Under the experimental conditions investigated, recoveries as high as 87% (cafestol) and 94% (kahweol) were achieved while detection limits equal to 0.06 and 0.04 ppm for cafestol and kahweol, respectively, were obtained. Examples are given comparing levels of cafestol and kahweol resulting from the same ground roasted coffee by different brewing methods, which show the lowest values for brews prepared from coffee bags.

Cholesterol↗
PubMed2000

Potent odorants of raw Arabica coffee. Their changes during roasting.

Aroma extract dilution analysis of raw Arabica coffee revealed 3-isobutyl-2-methoxypyrazine (I), 2-methoxy-3,5-dimethylpyrazine (II), ethyl 2-methylbutyrate (III), ethyl 3-methylbutyrate (IV), and 3-isopropyl-2-methoxypyrazine (V) as potent odorants. The highest odor activity value was found for I followed by II, IV, and V. It was concluded that I was responsible for the characteristic, peasy odor note of raw coffee. Twelve odorants occurring in raw coffee and (E)-beta-damascenone were also quantified after roasting. The concentration of I did not change, whereas methional, 3-hydroxy-4, 5-dimethyl-2(5H)-furanone, vanillin, (E)-beta-damascenone, and 4-vinyl- and 4-ethylguaiacol increased strongly during the roasting process.

Chromatography, Gas↗
PubMed1997

Bladder cancer, tobacco smoking, coffee and alcohol drinking in Brescia, northern Italy.

The association between tobacco smoking, the consumption of coffee and alcohol and bladder cancer was investigated in a hospital-based case-control study in Brescia, northern Italy. A total of 172 incident cases (135 men and 37 women) and 578 controls (398 men and 180 women) were enrolled. As expected, cigarette smoking was strongly associated with bladder cancer. The odds ratios (OR) for coffee drinking adjusted for age, education, residence and cigarette smoking in current drinkers were 2.6 (95% confidence interval, CI: 1.1-6.1) in men and 5.2 (95% CI: 1.0-30.4) in women. A dose-response relationship was found in men, with the highest risk in the highest category of exposure: drinkers of more than 5 cups per day had an OR of 4.5 (95% CI: 1.2-16.8). The ORs for current alcohol drinkers were 2.1 (95% CI: 1.0-4.8) in men and 3.4 (95% CI: 1.2-9.7) in women; according to grams of ethanol drunk per day (grams/day, g/d) the ORs were: 1.7 (1-20 g/d), 1.6 (21-40 g/d), 4.3 (41-60 g/d) and 4.6 (61+ g/d) in men and 3.1 (1-20 g/d) and 3.9 (21+ g/d) in women. These results suggest that regular consumption of both coffee and alcohol can be independently associated with an increased bladder cancer risk.

Aged↗
PubMed2000

Heavy coffee drinking and the risk of suicide.

Earlier research has implicated coffee drinking as a possible protective factor for suicide. We followed-up 43,166 subjects for the mean 14.6 years, and 213 suicides were committed. Daily coffee drinking had a J-shaped association with the risk of suicide. Using the Cox model we controlled for potential covariates, and found that among heavy coffee drinkers (> or = 8 cups/day) the risk of suicide was 58% higher compared with more moderate drinkers.

Adult↗
PubMed1998

Tea and coffee consumption and the risk of digestive tract cancers: data from a comparative case-referent study in Japan.

OBJECTIVES: The purpose of this study was to examine the hypothesis that tea and coffee consumption have a protective effect against development of digestive tract cancers. METHODS: A comparative case-referent study was conducted using Hospital-based Epidemiologic Research Program at Aichi Cancer Center (HERPACC) data from 1990 to 1995 in Nagoya, Japan. This study comprised 1,706 histologically diagnosed cases of digestive tract cancers (185 esophagus, 893 stomach, 362 colon, 266 rectum) and a total of 21,128 non-cancer outpatients aged 40 years and over. Logistic regression was used to analyze the data, adjusting for gender; age; year and season at hospital-visit; habitual smoking and alcohol drinking; regular physical exercise; fruit, rice, and beef intake; and beverage intake. RESULTS: The odds ratio (OR) of stomach cancer decreased to 0.69 (95 percent confidence interval [CI] = 0.48-1.00) with high intake of green tea (seven cups or more per day). A decreased risk was also observed for rectal cancer with three cups or more daily intake of coffee (OR = 0.46, CI = 0.26-0.81). CONCLUSIONS: The results suggest the potential for protective effect against site-specific digestive tract cancer by consumption of green tea and coffee, although most associations are limited only to the upper category of intake and have no clear explanation for site-specificity.

Adult↗
PubMed2003

Coffee drinking: the rationale for treating it as a potential effect modifier of carcinogenic exposures.

Clinical and epidemiological studies on cancer etiology seldom treat coffee drinking as a potential effect modifier. Yet caffeine exerts significant effects upon a large variety of physiologic, cellular and molecular systems. Caffeine, 'the world's most popular drug', is also a fundamental research tool, widely used in clinical studies on drug metabolism, and in experimental studies on cell cycle checkpoints, DNA repair, and apoptosis, among many other. Caffeine can profoundly alter cell cycle checkpoint function and several mechanisms of DNA repair, as well as carcinogen metabolism. The impact of caffeine on cell cycle checkpoint function occurs in spite of it being nonmutagenic in traditional mutagenesis assays. A complex body of biologic evidence suggests that caffeine-containing beverages can both enhance and antagonise potentially carcinogenic exposures. However, most pathways leading to the ultimate effects in human beings remain unknown. It is unclear whether any of the hundreds of compounds contained in coffee and tea exert a direct and significant carcinogenic effect per se in any human tissue at usual conditions of use. Reasons exist to consider that coffee may sometimes be an indirect, positive confounder. The study of interactions between caffeine-containing beverages and environmental agents in well defined groups of healthy and diseased people could yield new insights into checkpoint signal transduction and other mechanisms of carcinogenesis. Information on the use of caffeine-containing beverages should more often be integrated in studies on the role of gene-environment interactions in the pathogenesis of cancer.

Coffee↗
PubMed2005

[Coffee--poison or medicine?].

Intake of coffee, one of the most common beverages worldwide, has often been discussed as a potential cardiovascular risk factor. However, definitive data about this topic are missing and newer studies even point out for a favorable rather than hazardous effect. Despite many studies no clear association between coffee and the risk of hypertension, myocardial infarction and other cardiovascular diseases was found. Recent publications suggest that moderate coffee intake does not represent a health hazard, but may even be associated with beneficial effects on the cardiovascular system and diabetes.

Cardiovascular Diseases↗
PubMed2002

The value of bees to the coffee harvest.

The self-pollinating African shrub Coffea arabica, a pillar of tropical agriculture, was considered to gain nothing from insect pollinators. But I show here that naturalized, non-native honeybees can augment pollination and boost crop yields by over 50%. These findings, together with world coffee-harvest statistics and results from field studies of organically shade-grown coffee, indicate that coffee plants would benefit from being grown in habitats that are suitable for sustaining valuable pollinators.

Animals↗
PubMed1982

Coffee and caffeine and alcohol effects on psychomotor function.

Interactions of alcohol and caffeine were studied in two double-blind and crossover trials in which several psychophysiologic functions and subjective effects were measured in healthy men. The effects of alcohol (1 gm/kg) with and without caffeine (200 or 500 mg) were measured in 10 subjects. Two doses (0.7 or 1.5 gm/kg) of alcohol alone and in combination with caffeine (250 + 250 mg) were similarly studied in another 10 subjects. Alcohol impaired psychomotor functions to an extent dependent on dose whereas caffeinated and decaffeinated coffee did not. Both kinds of coffee also failed to modify alcohol effects. Subjectively, caffeine was indistinguishable from placebo and no particular interaction of alcohol and caffeine was detected. Alcohol did elevate serum caffeine concentrations. We conclude that coffee does not counteract alcohol inebriation.

Adult↗
PubMed2006

Coffee drinking and risk of preterm birth.

OBJECTIVES: We analysed the association between coffee drinking before and during the three trimesters of pregnancy and the risk of preterm birth of babies normal for gestational age (NGA) or small for gestational age (SGA). METHODS: Case-control study conducted in University clinics of North Italy. Cases were 502 women who delivered at <37 weeks of gestation. The controls included 1966 women who gave birth at term (>or=37 weeks of gestation) to healthy infants on randomly selected days at the hospitals where cases had been identified. RESULTS: There was inverse association for coffee consumption in the third trimester of pregnancy in SGA cases compared to NGA (heterogeneity test between OR: chi1(2)=5.6811 P<0.05). In comparison with not drinkers, all the ORs of overall intake of caffeine were closed near the unity for both SGA and NGA preterm birth. CONCLUSION: Compared with no consumption, a low consumption of coffee during pregnancy may not have significant effects on preterm birth.

Adolescent↗
PubMedDate not supplied

Acute health effects of organophosphorus pesticides on Tanzanian small-scale coffee growers.

Acute health effects of organophosphorus (OP) pesticides on coffee farmworkers in 1991-1992 in Tanzania are reported to provide a basis for concern over farmworkers being overexposed during application. Workers exposed to OP pesticides (N=133) were drawn from a population of about 240,000 coffee farmers. They were interviewed on symptoms and personal protection, and their erythrocyte acetylcholinesterase (AChE) activity was determined during both spraying and nonspraying period. AChE activities during spraying and nonspraying period were comparable (mean 32.0, SD 7.8 vs. 33.0, SD 8.7 U/g HgB, P=0.26). The prevalence of cough, headache, abdominal pain, excessive sweating, nausea, excessive salivation, diarrhea, and vomiting did not differ significantly between spraying and nonspraying periods. There was no suggestion of decreased AChE in exposed subjects who complained of OP-related symptoms compared to symptomless exposed subjects. Use of gloves, long boots, head cover, face cover, and coverall was not significantly associated with AChE activity. No marked AChE depression was found during spraying season, which may explain the lack of association between symptoms and AChE. The fact that only moderately toxic OP pesticides were used may indicate that toxicity was not sufficiently high to cause depression. Experience, however, suggests that occupational poisoning remains a potential serious danger in coffee cultivation in Tanzania.

Abdominal Pain↗
PubMed1976

Coffee drinking and death due to coronary heart disease.

For a series of 649 patients who died of coronary heart disease within 24 hours of onset of symptoms, and an equal number of neighborhood controls, information was obtained on a large number of variables, including coffee consumption. An analysis using multivariate risk scores to control for all available variables yields a maximum likelihood estimate of the risk ratio associated with coffee drinking of 1.1 (95 per cent two-sided confidence limits, 0.8 to 1.6). The estimate of the risk ratio depends somewhat on the number and nature of variables controlled for in the analysis. Overall, our findings, limited to low-risk and middle-risk patients, suggest that the risk, if any, of death from coronary heart disease associated with coffee drinking is small.

Adult↗
PubMed2004

Economic value of tropical forest to coffee production.

Can economic forces be harnessed for biodiversity conservation? The answer hinges on characterizing the value of nature, a tricky business from biophysical, socioeconomic, and ethical perspectives. Although the societal benefits of native ecosystems are clearly immense, they remain largely unquantified for all but a few services. Here, we estimate the value of tropical forest in supplying pollination services to agriculture. We focus on coffee because it is one of the world's most valuable export commodities and is grown in many of the world's most biodiverse regions. Using pollination experiments along replicated distance gradients, we found that forest-based pollinators increased coffee yields by 20% within approximately 1 km of forest. Pollination also improved coffee quality near forest by reducing the frequency of "peaberries" (i.e., small misshapen seeds) by 27%. During 2000-2003, pollination services from two forest fragments (46 and 111 hectares) translated into approximately 60,000 USD per year for one Costa Rican farm. This value is commensurate with expected revenues from competing land uses and far exceeds current conservation incentive payments. Conservation investments in human-dominated landscapes can therefore yield double benefits: for biodiversity and agriculture.

Animals↗
PubMed2000

7-Methylxanthine methyltransferase of coffee plants. Gene isolation and enzymatic properties.

Caffeine is synthesized through sequential three-step methylation of xanthine derivatives at positions 7-N, 3-N, and 1-N. However, controversy exists as to the number and properties of the methyltransferases involved. Using primers designed on the basis of conserved amino acid regions of tea caffeine synthase and Arabidopsis hypothetical proteins, a particular DNA fragment was amplified from an mRNA population of coffee plants. Subsequently, this fragment was used as a probe, and four independent clones were isolated from a cDNA library derived from coffee young leaves. Upon expression in Escherichia coli, one of them was found to encode a protein possessing 7-methylxanthine methyltransferase activity and was designated as CaMXMT. It consists of 378 amino acids with a relative molecular mass of 42.7 kDa and shows similarity to tea caffeine synthase (35.8%) and salicylic acid methyltransferase (34.1%). The bacterially expressed protein exhibited an optimal pH for activity ranging between 7 and 9 and methylated almost exclusively 7-methylxanthine with low activity toward paraxanthine, indicating a strict substrate specificity regarding the 3-N position of the purine ring. K(m) values were estimated to be 50 and 12 microM for 7-methylxanthine and S-adenosyl-l-methionine, respectively. Transcripts of CaMXMT could be shown to accumulate in young leaves and stems containing buds, and green fluorescent protein fusion protein assays indicated localization in cytoplasmic fractions. The results suggest that, in coffee plants, caffeine is synthesized through three independent methylation steps from xanthosine, in which CaMXMT catalyzes the second step to produce theobromine.

Amino Acid Sequence↗
PubMed2006

Coffee berry borer Hypothenemus hampei (Coleoptera: Curculionidae): searching for sustainable control strategies.

The coffee berry borer Hypothenemus hampei (Ferrari) is the most serious pest of the world's most valuable tropical export crop. Since the last review on this insect was published six years ago, many new studies have contributed to an improved insight into the biology and ecology of the beetle, and have indicated new avenues for integrated and biological control. The latest developments in research, both laboratory and field, on the pest, its natural enemies and their implications for integrated control of H. hampei are summarized, with a particular focus on the situation in The Americas. Lately, the global coffee industry has changed radically; it has suffered a long cycle of lowest-ever world market prices caused by overproduction and technological change. At the same time, the advent of sustainable certification schemes has had a major impact on the industry. The role of integrated pest management and biological control of H. hampei in an era of changes in the coffee industry is discussed.

Agriculture↗
PubMed1983

The influence of dietary tea, coffee and cocoa on protein and energy utilization of soya-bean meal and barley in rats.

Two series of balance experiments were performed with growing rats to test the effect of black tea, green tea, coffee and cocoa on protein and energy utilization. In Expt 1 soya-bean meal was fed as a basal diet and supplemented with freeze-dried materials from 11 black tea, green tea or coffee/500 g dry matter. Cocoa powder, corresponding to 11 of the beverage, was also added to the basal diet. In Expt 2 the procedure was repeated with a barley-based diet. In both experiments both tea varieties and coffee had significantly negative effects on true protein digestibility and biological value, while digestible energy was only slightly affected in the barley-based diet. Cocoa had no effect on protein or energy utilization in either soya-bean meal or barley diets, although the protein in cocoa powder was completely indigestible. As the tannin concentration in both tea varieties and coffee was very high it is assumed that the observed deleterious effects might, in part, be explained by anti-nutritional effects of tannin. The strongest deleterious effect was recorded for black tea.

Amino Acids↗