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PubMedDate not supplied

Testing green coffee for ochratoxin A, part I: estimation of variance components.

The variability associated with testing lots of green coffee beans for ochratoxin A (OTA) was investigated. Twenty-five lots of green coffee were tested for OTA contamination. The total variance associated with testing green coffee was estimated and partitioned into sampling, sample preparation, and analytical variances. All variances increased with an increase in OTA concentration. Using regression analysis, mathematical expressions were developed to model the relationship between OTA concentration and the total, sampling, sample preparation, and analytical variances. The expressions for these relationships were used to estimate the variance for any sample size, subsample size, and number of analyses for a specific OTA concentration. Testing a lot with 5 microg/kg OTA using a 1 kg sample, Romer RAS mill, 25 g subsamples, and liquid chromatography analysis, the total, sampling, sample preparation, and analytical variances were 10.75 (coefficient of variation [CV] = 65.6%), 7.80 (CV = 55.8%), 2.84 (CV = 33.7%), and 0.11 (CV = 6.6%), respectively. The total variance for sampling, sample preparation, and analytical were 73, 26, and 1%, respectively.

Algorithms↗
PubMed2004

[Does coffee consumption represent a coronary risk factor?].

Aim of this paper is to critically review the evidence available regarding the relationship between coffee consumption and coronary risk. Large prospective studies do not support the hypothesis that moderate (< 5 cups of coffee a day) caffeine consumption significantly increases the risk of coronary heart disease. Data on higher coffee consumption are scanty and do not allow the acquisition of established conclusions, even if they suggest a statistically significant trend in coronary risk with increasing dose.

Caffeine↗
PubMedDate not supplied

Determination of ochratoxin A in green coffee by immunoaffinity column cleanup and liquid chomatography: collaborative study.

A collaborative study was conducted to evaluate a method using immunoaffinity column cleanup with liquid chromatography (LC) for the determination of ochratoxin A (OTA) in green coffee at levels that could be included in possible future regulations of the European Union. The test portion was extracted with methanol-3% aqueous sodium hydrogen carbonate solution (50 + 50, v/v). The extract was filtered, and the filtrate was diluted with phosphate-buffered saline and applied to an immunoaffinity column containing antibodies specific for OTA. After washing, the toxin was eluted from the column with methanol and quantified by LC with fluorescence detection. Pairs of 4 homogeneous noncontaminated and naturally contaminated materials (mean levels of < 0.12, 2.44, 5.15, and 13.46 ng/g) and blank samples (< 0.12 ng/g) for spiking were sent to 20 participant laboratories from 8 countries. The materials were analyzed according to the method description and all difficulties encountered in the analysis were reported. Statistical analysis was carried out according to the Harmonized Protocol of the International Union of Pure and Applied Chemistry. The relative standard deviation for repeatability (RSDr) ranged from 7.42 to 20.94%, and the relative standard deviation for reproducibility (RSDR) ranged from 16.34 to 29.17%. The method showed acceptable within-laboratory and between-laboratories precision for green coffee materials, as evidenced by HorRat values of < or = 0.85, at the studied range, for spiked and naturally contaminated materials. The mean recovery was 92.8% for green coffee material spiked with OTA at a level of 4.82 ng/g.

Buffers↗
PubMedDate not supplied

Testing green coffee for ochratoxin A, part II: Observed distribution of ochratoxin A test results.

The suitability of 4 theoretical distributions (normal, lognormal, negative binomial, and gamma) to predict the observed distribution of ochratoxin A (OTA) in green coffee was investigated. One symmetrical and 3 positively skewed theoretical distributions were each fitted to 25 empirical distributions of OTA test results for green coffee beans. Parameters of each theoretical distribution were calculated by using Methods of Moments. The 3 skewed theoretical distributions provided acceptable fits to each of the 25 observed distributions. Because of its simplicity, the lognormal distribution was selected to model OTA test results for green coffee. Using variance equations determined in previous studies, mathematical expressions were developed to calculate the parameters of the log normal distribution for a given OTA lot concentration and test procedure. Observed acceptance probabilities were compared to an operating characteristic curve predicted from the lognormal distribution, and all 25 observed acceptance probabilities were found to lie within the 95% confidence band associated with the predicted operating characteristic curve. The parameters of compound gamma distribution were used to calculate the fraction of OTA contamination beans within a contaminated lot. The percent-contaminated beans were a function of the lot concentration and increased with lot concentration. At a lot concentration of 5 microg/kg, approximately 6 beans per 10,000 beans are contaminated.

Buffers↗
PubMed2005

[Tea and coffee consumption among Russian population].

Aim of present study was the getting data on black and green tea and coffee consumption among Russian population in 1995-2003. The consumption of beverages tea and coffee was estimated by 24-hour recall of dietary intake in course of Russian Longitudinal monitoring surveys of economics and health. About 82% of population have consumed the black tea and only 2.2%--the green tea. Mean daily black and green tea intake among all population were 446 ml and 10 ml, correspondingly. The prevalence of black tea consumption was decreased and green tea and coffee consumption were increased from 1995 to 2003.

Adolescent↗
PubMedDate not supplied

Testing green coffee for ochratoxin A, part III: performance of ochratoxin A sampling plan.

Green coffee shipments are often inspected for ochratoxin A (OTA) and classified into good or bad categories depending on whether the OTA estimates are above or below a defined regulatory limit. Because of the uncertainty associated with the sampling, sample preparation, and analytical steps of an OTA test procedure, some shipments of green coffee will be misclassified. The misclassification of lots leads to some good lots being rejected (sellers' risk) and some bad lots being accepted (buyers' risk) by an OTA sampling plan. Reducing the uncertainty of an OTA test procedure and using an accept/reject limit less than the regulatory limit can reduce the magnitude of one or both risks. The uncertainty of the OTA test procedure is most effectively reduced by increasing sample size (or increasing the number of samples analyzed), because the sampling step is the largest source of uncertainty in the OTA test procedure. The effects of increasing sample size and changing the sample accept/reject limit relative to the regulatory limit on the performance of OTA sampling plans for green coffee were investigated. For a given accept/reject limit of 5 microg/kg, increasing sample size increased the percentage of lots accepted at concentrations below the regulatory limit and increased the percentage of lots rejected at concentrations above the regulatory limit. As a result, increasing sample size reduced both the number of good lots rejected (sellers' risk) and the number of bad lots accepted (buyers' risk). For a given sample size (1 kg), decreasing the sample accept/reject limit from 5 to 2 microg/kg relative to a fixed regulatory limit of 5 microg/kg decreased the percentage of lots accepted and increased the percentage of lots rejected at all OTA concentrations. As a result, decreasing the accept/reject limit below the regulatory limit increased the number of good lots rejected (sellers' risk), but decreased the number of bad lots accepted (buyers' risk).

Carcinogens↗
PubMedDate not supplied

Mass spectrometric confirmation of the presence of N-nitrosopyrrolidine in instant coffee.

Traces of N-nitrosopyrrolidine (NPYR) may occur in some samples of both instant coffee and fine-ground roasted coffee. The identity of NPYR in 2 samples of instant coffee was confirmed by mass spectrometry as well as by liquid chromatography-thermal energy analysis. A 2-step cleanup procedure, involving fractionation on basic alumina followed by gradient elution on reverse-phase C18 cartridge, is described that allows full-scan mass spectrometric confirmation of NPYR in tested samples.

Chromatography, Gas↗
PubMed1988

Acute effect of decaffeinated coffee on heart rate, blood pressure, and exercise performance in healthy subjects.

The effect of decaffeinated coffee on the cardiovascular exercise performance in nine healthy volunteers was evaluated in a double-blind randomized fashion. The heart rate, blood pressure, and duration of exercise were unchanged, and no arrhythmias or ischemic changes were seen on the electrocardiogram after drinking decaffeinated coffee. It was concluded that decaffeinated coffee has no discernible, acute, adverse cardiovascular effects.

Adult↗
PubMed1986

[Effect of roasting on the chromatographic profile obtained by gel filtration of Arabian coffee extract].

Gel filtration chromatography under a high pressure system was used to investigate green and roasted coffee aqueous extracts. Chromatographic columns used were of the type TSK-PW 4000, in series. Chromatography of the extracts was monitored either using a refractive index (RI) detector in series with an ultraviolet (UV) detector at 420 nm or with two UV detectors at 280 and 325 nm, respectively. The utilization of RI detection showed significant differences in the molecular weight profile between green and roasted coffees. UV detection at 280 and 325 nm revealed similar chromatographic patterns, suggesting that phenolic compounds were probably bound to proteins. Pigment formation after roasting was monitored by detection at 420 nm, showing that colored material was distributed throughout the molecular weight range studied. The method provided a more rapid analysis compared to traditional gel filtration chromatography and proved to be useful for monitoring changes in molecular weight profile which occur during coffee roasting.

Chromatography, Gel↗
PubMed1985

Coffee and methylxanthines and breast cancer: a case-control study.

A dietary case-control study based on 818 newly diagnosed breast cancer (BC) patients was conducted in Israel between 1975 and 1978. The role of coffee and total methylxanthine intake from coffee, tea, cola, chocolate, and cocoa drinks was evaluated in the BC patients as compared to that in two matched control populations [surgical controls (SC) and neighborhood controls (NC)]. Because it has been suggested that caffeine enhances mammary carcinogenesis in rats fed high polyunsaturated fat diets, analysis was done also in relation to fat consumption. When comparison was done to both matched control groups, a nonsignificant negative association was found between consumption of cups of coffee and BC (odds ratios of greater than or equal to 4 cups of coffee/day vs. less than or equal to 1 per week = 0.6 for BC/NC and 0.7 for BC/SC). This association was observed in all 3 ethnic subgroups studied. The pattern was stronger among the high-fat consumers after controlling for several hormonal confounding factors (two-tailed P-value for linear trend = 0.06 for SC and P = 0.05 for NC). In addition, when the consumption of methylxanthine of BC patients was compared to that of benign breast patients, adjusted by age and ethnic group, a diminished risk was found (odds ratio for BC of the highest level of methylxanthine vs. lowest level = 0.59).

Adult↗
PubMed1985

Tobacco smoking, coffee drinking, and occupation as risk factors for bladder cancer in Greece.

Patients with bladder cancer (250 males and 50 females), consecutively admitted during a 2-year period in the major cancer hospital of Athens, and an equal number of age- and gender-matched comparison patients with orthopedic conditions were interviewed regarding demographic, socioeconomic, and biomedical characteristics, including their occupations and their use of coffee and tobacco prior to the onset of their present disease or condition. Analyses of the data showed that cigarette smoking is an important, statistically significant and dose-dependent risk factor for bladder cancer, particularly in males (tobacco smoking is rare among older Greek women); drinking 2 or more cups of Greek coffee per day appears to be a risk factor for bladder cancer, independent of tobacco smoking, although the association is neither strong nor dose dependent; and a priori specified "high-risk" occupations were associated with an increased rate ratio for bladder cancer among men less than 65 years and among women in general but not among older men. The overall results of this study indicate that the established risk factors for bladder cancer in the United States and in other developed countries are, apparently, equally important for bladder cancer in Greece, despite the differences in composition and conditions of use of Oriental tobacco and Greek coffee and in the activities and exposures to carcinogens in the Greek work place.

Age Factors↗
PubMed1982

Effect of coffee and cigarette smoking on the blood pressure of untreated and diuretic-treated hypertensive patients.

Patients with mild hypertension who habitually smoked cigarettes and consumed caffeine were examined after they abstained from caffeine and cigarettes overnight. Their mean blood pressure (147/89 mm Hg) was substantially lower than values recorded in the clinic (164/102 mm Hg) and remained so when they continued to abstain (149/94 mm Hg at two hours). Smoking two cigarettes (3.4 mg nicotine) elevated blood pressure by 10/8 mm Hg, but for only 15 minutes. Drinking coffee (200 mg caffeine) elevated blood pressure by up to 10/7 mm Hg between one and two hours. Combined coffee ingestion and cigarette smoking caused a sustained rise in blood pressure from 5 to 120 minutes to levels similar to those measured in the clinic (162/102 mm Hg at two hours). Similar results were obtained in thiazide-treated patients. The interaction of coffee and cigarettes on blood pressure, but not on pulse rate, was significant. The pressor effect of cigarette smoking and caffeine ingestion in combination may be important in the evaluation of patients with mild hypertension.

Adult↗
PubMedDate not supplied

The thermic effect of caffeinated and decaffeinated coffee ingested with breakfast.

The thermic effect of caffeinated and decaffeinated coffee ingested with a standard breakfast was studied in 8 healthy subjects with indirect calorimetry. A higher increase in the metabolic rate was observed after ingestion of the breakfast with coffee containing caffeine than after that with coffee deprived of caffeine.

Adult↗
PubMed1980

Mycotoxins in coffee.

This report reviews studies concerning the susceptibility of green coffee beans to mycotoxin contamination. Included are investigations on normal mold flora, toxin production in inoculated beans, effect of experimental roasting on aflatoxin, ochratoxin, and sterigmatocystin, and survey on the presence of these toxins in commercial green coffee. Because of the extremely low frequency of findings, the low levels of toxins, and the experimental data showing 70--80% destruction by the roasting process of toxin added to green coffee, further study on this topic has been discontinued.

Coffee↗
PubMedDate not supplied

Determination of carbohydrates in soluble coffee by anion-exchange chromatography with pulsed amperometric detection: interlaboratory study.

A collaborative study was conducted to validate a liquid chromatographic (LC) method to determine the free and total (after acid hydrolysis) carbohydrate profile of soluble coffee. Carbohydrates were separated on a pellicular anion-exchange column using pure water as mobile phase, and were detected by pulsed amperometry. Eleven collaborators were sent 6 test samples of commercial soluble coffee for duplicate analysis. They were also sent a practice sample with known levels of free and total carbohydrates and material for preparation of all standard solutions. The reproducibility relative standard deviations (RSDR) were 9.9-59.5% for mannitol, 35.6-72.6% for fucose, 4.9-21.1% for arabinose, 4.1-13.0% for galactose, 6.1-24.3% for glucose, 10.0-41.6% for sucrose, 20.2-37.7% for xylose, 10.6-40.0% for mannose, 15.5-71.7% for fructose, and 17.8-97.9% for ribose. Precision in the determination of free and total carbohydrates was very similar. The average repeatability RSDr and RSDR values were 4.5 and 14.3%, respectively, for carbohydrate levels above 0.3%. The precision of the technique was considered good, regardless of the usual peak integration problems always encountered in LC, the low levels of free carbohydrates, the hydrolysis step, and the relative lack of experience of most participating laboratories. The method allows good and reproducible separation of all major carbohydrates found in soluble coffee and is, therefore, suitable for routine analysis.

Carbohydrates↗
PubMed1994

Coffee induced thermogenesis and skin temperature.

The purpose of this study was to investigate the relationship between the changes in mean skin temperature and the energy expenditure induced by drinking coffee containing 4 mg of caffeine/kg body weight. Twelve healthy, weight-stable subjects were studied (five males, seven females; mean age +/- s.d., 25.3 +/- 3.3 years; BMI 22.5 +/- 3.1). Energy expenditure (EE) was measured by open-circuit indirect calorimetry, and skin temperature was determined with thermometric probes applied to the four body regions indicated by Ramanathan (chest, arm, thigh, calf). The calorimetric and thermometric measurements were carried out for 120 min with the participants lying down quietly. A significant correlation was found between the total thermogenic responses (net responses) and the temperature changes between 90 and 120 min from the coffee intake. Multiple regression analysis using mean EE after coffee intake as the dependent variable, and mean skin temperature and body weight as the independent variables yields the following equation: EE (kcal/min/m2) = -1.44 + 0.052 (mean skin temperature) + 0.004 (body weight). (r = 0.71 and P = 0.01) Our results indicate that small interindividual differences in mean skin temperature could explain energy expenditure differences in subjects with the same body weight, body composition and physical activity. This, in turn, could help explain variations in proneness to obesity.

Adult↗
PubMed1994

[Life-threatening caffeine poisoning by using coffee as a psychoactive drug].

A 27 year-old deeply unconscious male patient with shallow spontaneous respiration was admitted to hospital following an epileptoid convulsion with a tentative diagnosis of cerebral trauma. On admission he was noted to have hyperpyrexia, tachycardia and hypertension. The clinical and laboratory findings pointed to intoxication. Aspiration of the stomach produced a large amount of coffee grounds, but not tablets or other poison. The plasma caffeine level was 29 micrograms/ml, which is potentially lethal. Therapy was commenced with a beta-blocker, an anticonvulsive drug and an antipyretic, and supportive symptomatic measures were undertaken. After 12 hours the patient was fully conscious, orientated and cooperative. He subsequently admitted having ingested about 500 g ground coffee with the intention of obtained a "high" state of drug intoxication, which he had successfully achieved on previous occasions with a smaller amount of coffee and without complications. The clinical picture was consistent with the expected signs of caffeine intoxication whereby the central effects of the substance remain to be clarified. This appears to be the first report of caffeine misused in this manner. In cases of intoxication with convulsions of uncertain aetiology, caffeine poisoning should be considered in the differential diagnosis.

Adult↗
PubMed1993

[Coffee and caffeine. Various selected aspects for everyday practice].

Moderate consumption of methylxanthines, for example in coffee, tea, cola-drinks and other foodstuffs containing caffeine, is probably without particular health risks, insofar as other risk factors (smoking, alcohol, nutrition in general) can be kept under control. To avoid prohibition on one hand and to evaluate necessary restrictions concerning caffeine consumption individually on the other hand is an artful task in daily medical practice. Coffee is one of the chemically most complex consumables, and its physiologic effects are accordingly complex and to a great deal still unknown. Caffeine in moderate amounts has practically neither a negative effect on health nor does it promote pathogenesis of disease. Only excessive use may induce problems. Therefore, excessive use of caffeine is assumed in those persons, in which withdrawal is followed by withdrawal symptoms (41). Many aspects of caffeine and biomedical caffeine effects cannot yet be explained. Nevertheless, from the medical point of view, there are no objections to a moderate use of caffeine with one exception: if the coffee break is used as a pretext for smoking.

Arrhythmias, Cardiac↗