Bohn, M.; Leppchen, K.; Katzberg, M.; Lang, A.; Steingroewer, J.; Weber, J.; Bley, T.; Bertau, M.
Caffeine affects the stereoselectivity of microbial high cell density reductions with commercial grade Saccharomyces cerevisiae (Baker\'s yeast). Cyclic beta-keto esters ethyl 2-oxocyclopentanoate (1) and ethyl 2-oxocyclohexanoate (3) were shown to be reduced with increased diastereoselectivity (1: 90.1 --> 92.1% de, 3: 75.0 --> 90.0% de) after addition of caffeine. Effects on enantioselectivity were less pronounced (1: 97.3 --> 98.5% ee, 3: 90.1 --> 92.1% ee). The observations are ascribed to the action of caffeine on cellular calcium homeostasis. These effects are accompanied by caffeine-induced cell-death, which preferably takes effect on pre-stressed cells which were found to decrease diastereoselectivity.
Lee, J. E.; Hunter, D. J.; Spiegelman, D.; Adami, H. O.; Bernstein, L.; van den Brandt, P. A.; Buring, J. E.; Cho, E.; English, D.; Folsom, A. R.; Freudenheim, J. L.; Gile, G. G.; Giovannucci, E.; Horn-Ross, P. L.;
Leitzmann, M.; Marshall, J. R.; Mannisto, S.; McCullough, M. L.; Miller, A. B.; Parker, A. S.; Pietinen, P.;
Rodriguez, C.; Rohan, T. E.; Schatzkin, A.; Schouten, L. J.; Willett, W. C.; Wolk, A.; Zhang, S. M.; Smith-
Warner, S. A.
Specific beverage intake may be associated with the risk of renal cell cancer through a diluting effect of carcinogens, alterations of hormone levels, or other changes in the renal tubular environment, but few prospective studies have examined these associations. We evaluated the associations between coffee, tea, milk, soda and fruit and vegetable juice intakes and renal cell cancer risk in a pooled analysis of 13 prospective studies (530,469 women and 244,483 men). Participants completed a validated food frequency questionnaire at baseline. Using the primary data, the study-specific relative risks (RRs) were calculated and then pooled using a random effects model. A total of 1,478 incident renal cell cancer cases were identified during a follow-up of 7-20 years across studies. Coffee consumption was associated with a modestly lower risk of renal cell cancer (pooled multivariate RR for 3 or more 8 oz (237 ml) cups/day versus less than one 8 oz (237 ml) cup/day = 0.84; 95% CI = 0.67-1.05; p value, test for trend = 0.22). Tea consumption was also inversely associated with renal cell cancer risk (pooled multivariate RR for 1 or more 8 oz (237 ml) cups/day versus nondrinkers = 0.85; 95% CI = 0.71-1.02; pvalue, test for trend = 0.04). No clear associations were observed for milk, soda or juice. Our findings provide strong evidence that neither coffee nor tea consumption increases renal cell cancer risk. Instead, greater consumption of coffee and tea may be associated with a lower risk of renal cell cancer.
Saragoni, P.; Aguilera, J. M.; Bouchon, P.
Caking of powders is deleterious, and the study of particle deformation under gravity, as a function of time and under controlled environmental conditions, indicates caking tendency. This study followed structural changes in amorphous particles of coffee powder in real time using videomicroscopy, to determine the effect of temperature and RH on the projected area (PA) of particles, and to develop a caking index based on changes of PA. Advantages of using videomicroscopy to evaluate deformation of a material are discussed, and the authors suggest that the PA method could be used to predict the tendency to caking of amorphous particles.
Source : Food Chem 2007 104 (1), pp 122-126
Graziani, G.; Napolitano, A.; Somma, M. C.; Ritieni, A.
A study of the different varieties of coffee silverskin was carried out to to select the better health-promoting CS functional ingredient. It was carried out mainly to realise the differences in terms of chemical composition and antioxidant activity between two widespread coffee varieties � Arabica and Robusta. CS is a tegument of coffee beans (the outer layer)?which is a by-product of the roasting procedure. CS is used in Western countries as a fertiliser and combustible but is a potential functional ingredient in food because of its content of soluble fibre and its antioxidant activity. Samples analysed took in seven commercial coffee varieties. This article gives details of the result of the survey.
Source : Innovations in Food Technology 2007 vol. 36), pp 60 - 61
Marques-de-Carvalho, J.; Arraes-Maia, G.; Wilane-de-Figueiredo, R.; Sousa-de-Brito, E.; Rordrigues, S.
The objective of this study was to evaluate the acceptability of coconut water/cashew apple juice blends containing 100 ppm of added caffeine. 5 formulations with different concn. of cashew apple juice, previously standardized with respect to pH values, TSS (°Brix) and caffeine contents, were evaluated. The formulations were subjected to chemical characterisation (pH, soluble solids, acidity, total sugar and vitamin C), microbial and sensory evaluation (colour, flavour, overall quality and purchase intention). All samples showed good acceptability, but the formulation containing 12.5% cashew apple juice and 87.5% coconut water achieved the highest hedonic scores. All formulations showed good microbiological quality. Vitamin C content varied considerably between formulations and depended on the amount of cashew apple juice present.
Source : Intern J Food Sci Technol 2007 vol.42 (10), pp 1195 - 1200
Matthews, W.; Webber, N.; Massey, R.
The formation and reduction of the carcinogenic processing contaminant 3-MCPD is discussed. Aspects considered include: formation of 3-MCPD in foods such as bread, biscuits, cheese, malt, coffee, smoked foods and fish; and steps manufacturers can take to reduce 3-MCPD formation, such as reducing salt and glycerol in bread.
Siu, Y.; Mejia, G.; Mejia-Saavedra, J.; Pohlan, J.; Sokolov, M.
One of the driving forces of the economy in southeast Mexico is agriculture. In Soconusco, Chiapas, coffee is one of the main agricultural products and is traded on the international market. Coffee grown in this region is processed using the wet method in order to be commercialized as green coffee. In the beneficio (coffee processing plant) water is an essential resource which is required in great quantities (Matuk et al., 1997; Sokolov, 2002) as it is used to separate good coffee berries from defective ones, as a method of transporting the coffee berries to the processing machinery, in the elimination of the berry husk from the coffee grains (pulping) and finally in the post-fermentation washing process. This process gives rise to one of the smoothest, high-quality coffees available (Zuluaga, 1989; Herrera, 2002). Currently, many producers in Soconusco are opting for ecological coffee production, which has, among its many criteria, human health and environmental protection (Pohlan, 2005). Furthermore, increasing concern during the past few years regarding the production of food that is free from contaminants such as heavy metals, and recent environmental policies in relation to aquatic ecosystem protection, have given rise to questions concerning the quality of water used in coffee processing, as well as pollutants produced by this agroindustry. Water used in the coffee processing plants originates from the main regional rivers whose hydrological basins stretch from the Sierra Madre mountain range down to the coastal plain. As well as providing water, these rivers also receive the wastewater produced during coffee processing (Sokolov, 2002).
Source : Bull Environ Contam Toxicol 2007 vol.78 (5), pp 400 - 404
Siu, Y.; Mejia, G.; Mejia-Saavedra, J.; Pohlan, J.; Sokolov, M.
One of the driving forces of the economy in southeast Mexico is agriculture. In Soconusco, Chiapas, coffee is one of the main agricultural products and is traded on the international market. Coffee grown in this region is processed using the wet method in order to be commercialized as green coffee. In the beneficio (coffee processing plant) water is an essential resource which is required in great quantities (Matuk et al., 1997; Sokolov, 2002) as it is used to separate good coffee berries from defective ones, as a method of transporting the coffee berries to the processing machinery, in the elimination of the berry husk from the coffee grains (pulping) and finally in the post-fermentation washing process. This process gives rise to one of the smoothest, high-quality coffees available (Zuluaga, 1989; Herrera, 2002). Currently, many producers in Soconusco are opting for ecological coffee production, which has, among its many criteria, human health and environmental protection (Pohlan, 2005). Furthermore, increasing concern during the past few years regarding the production of food that is free from contaminants such as heavy metals, and recent environmental policies in relation to aquatic ecosystem protection, have given rise to questions concerning the quality of water used in coffee processing, as well as pollutants produced by this agroindustry. Water used in the coffee processing plants originates from the main regional rivers whose hydrological basins stretch from the Sierra Madre mountain range down to the coastal plain. As well as providing water, these rivers also receive the wastewater produced during coffee processing (Sokolov, 2002).
Source : Bull Environ Contam Toxicol 2007 vol.78 (5), pp 400 - 404
Baggenstoss, J.; Poisson, L.; Luethi, R.; Perren, R.; Escher, F.
Coffee roasting experiments with air cooling vs water quench cooling were carried out on laboratory scale with a fluidized-bed hot air roasting system (200 g batch size) and on a production scale with a rotating bowl roaster (320 kg batch size). 2 series of coffees with different water contents resulted, which were stored at 25°C under normal atmospheric conditions. CO2 desorption was followed and stability of selected aroma compounds was tested with headspace solid-phase microextraction GC-MS and stable isotope labelled compounds as internal standards. Degassing was faster in water-quenched coffees with higher moisture content, but pore size distribution in the different coffee samples did not correlate with degassing behaviour. Bean firmness, which increased with increasing moisture content, might have an influence on degassing. Air- and water-quenched coffees exhibited similar stability of most aroma compounds despite different degassing behaviour. However, evolution of dimethyl trisulfide was different in coffees with increased water content. This suggests higher thiol oxidation rates, a factor that is cited to be related to a faster loss of freshness attributes.
Manzocco, L.; Nicoli, M. C.
The chemical stability of coffee brew derivatives as a function of aw and storage temp. was studied. Coffee brew was freeze-dried, equilibrated at increasing aw values and stored for <less than or equal to>10 months at different temp. from -30 to 60°C. The chemical stability of the samples was assessed by measuring H3O+ formation during storage. Independently of storage temp., the rate of H3O+ formation was low only when aw was reduced below 0.5 (94% w/w). Beyond this critical boundary, the rate increased, reaching a max. value at ca. 0.8 aw (78% w/w). Further hydration up to the aw of the freshly prepared beverage significantly increased chemical stability. It is suggested that mechanisms other than lactones\' hydrolysis, probably related to nonenzymic browning pathways, could contribute to the observed increase in acidity during coffee staling. The temp. dependence of H3O+ formation was well-described by the Arrhenius equation in the entire aw range considered. However, aw affected the apparent activation energy and frequency factor. These effects were described by simple equations that were used to set up a modified Arrhenius equation. This model was validated by comparing experimental values that were not used to generate the model with those estimated by the model itself. The model allowed efficient prediction of the chemical stability of coffee derivatives on the basis of only the aw value and storage temp.
Ramalakshmi, K.; Kubra, I. R.; Rao, L. J. M.
About 20% of the coffee bean harvest in India is rejected as it does not meet the quality requirements of the graded beans. This study examined the physical and chemical characteristics of these defective (triage) coffee beans with a view to finding a use for them. The results indicated that the physical parameters, such as density, weight and brightness of the defective beans were low compared with graded beans. Caffeine content was also low, but the content of chlorogenic acid was high, suggesting that they might find application as a source of antioxidants.
Source : J Food Sci 2007 72 (5), pp S333-S337
Mahramanlioglu, M.; Bicer, I. O.; Misirli, T.; Kilislioglu, A.
Large amounts of coffee residues contaminate the environment and reprocessing of them as valuable products such as adsorbents will be a good solution from an environmental and economic point of view. In this study some adsorbents were produced from coffee residues and used for batch removal experiments of uranium from aqueous solutions. The adsorption kinetics was found to follow the Lagergren equation. The adsorption process was described with the Langmuir and Freundlich isotherms. Additionally, the effect of different cations on the adsorption of uranium was studied.
Source : J Radioanal Nuclear Chem 2007 vol.273 (3), pp 621 - 624
Jae, Heun Chung; Seo, Young Choi; Ji, Young Kim; Dae, Hyun Kim; Jae, Won Lee; Jae, Sue Choi; Hae, Young Chung
Activation of the redox-sensitive transcription factor, nuclear factor-kappaB (NF-kappaB), plays a central role in inflammation and the ageing processes by inducing pro-inflammatory genes. This study was designed to unravel the molecular mechanisms underlying the anti-inflammatory effects of 3-methyl-1,2-cyclopentanedione (3-MCP) in coffee extracts. In particular, the effects of 3-MCP on the modulation of NF-kappaB signalling pathways and its target genes were investigated in the kidneys of aged animal rats: young (6 months old), old (21 months old) and old 3-MCP-fed (4 and 8 mg/kg/day for 10 days). Results strongly show that 3-MCP exerted potent anti-inflammatory effects, significantly reducing: the phosphorylation of inhibitor B and other NF-kappaB upstream events; the translocation of NF-kappaB into the nucleus; the expression of iNOS and COX-2; and pro-inflammatory genes such as VCAM-1, MCP-1 and IL-6. Furthermore, 3-MCP suppressed reactive oxygen species levels. Taken together, these results clearly demonstrate that 3-MCP modulated the age-related NF-kappaB signalling cascade and its proinflammatory genes. Therefore, 3-MCP is proposed to be an effective anti-inflammatory agent that can be a novel approach for the therapy of inflammation.
Murosaki, S.; Tae, Ryong Lee; Muroyama, K.; Eui, Seok Shin; Si, Young Cho; Yamamoto, Y.; Sang, Jun Lee
To develop an anti-obesity agent containing dietary components, we focused on the mechanisms that enhance both lipolysis and fatty acid oxidation. Caffeine and arginine (CA), a nonselective adenosinereceptor antagonist and an inducer of lipolytic hormone, respectively, were used to stimulate lipolysis. Soy isoflavones and L-carnitine (SL), stimulators of carnitine palmitoyl transferase 1A and a cofactor for betaoxidation of fatty acids, respectively, were used to enhance fatty acid oxidation. Effects of a combination of CA and SL (CASL) on lipid metabolism were studied in vitro and in vivo. During 3T3-L1 differentiation, lipid accumulation was significantly lower in cells treated with CASL (50 mumol/L, 1 mmol/L, 1 mumol/L, and 1 mmol/L, respectively) compared with each alone. Lipolysis was also significantly greater in 3T3-L1 adipocytes treated with CASL (50 mumol/L, 1 mmol/L, 10 mumol/L and 0.5 mmol/L, respectively) compared with each alone. In addition, treatment with higher concentrations of CASL (2 mmol/L, 1 mmol/L, 10 mumol/L, and 1 mmol/L, respectively) significantly enhanced beta-oxidation in HepG2 cells. The effects of CASL-containing diets (250 mg, 6 g, 200 mg, and 1.5 g/kg diet, respectively) were studied in vivo. When KK mice were food deprived for 48 h and subsequently refed a fat-free diet for 72 h, hepatic triglyceride (TG) accumulation was significantly lower in mice fed CASL compared with the control mice. In addition, after obese KK mice were fed a low-fat diet for 2 wk, adipose tissue weights were significantly lower in those fed CASL, but not CA or SL alone, compared with the control mice. Plasma and liver TG levels were also lower in mice fed CASL than in the control mice. These results suggest that CASL is effective for controlling obesity. (c)American Society for Nutrition. All rights reserved.
Daly, J. W.
Caffeine, widely consumed in beverages, and many xanthine analogs have had a major impact on biomedical research. Caffeine and various analogs, the latter designed to enhance potency and selectivity toward specific biological targets, have played key roles in defining the nature and role of adenosine receptors, phosphodiesterases, and calcium release channels in physiological processes. Such xanthines and other caffeine-inspired heterocycles now provide important research tools and potential therapeutic agents for intervention in Alzheimer\'s disease, asthma, cancer, diabetes, and Parkinson\'s disease. Such compounds also have activity as analgesics, antiinflammatories, antitussives, behavioral stimulants, diuretics/natriuretics, and lipolytics. Adverse effects can include anxiety, hypertension, certain drug interactions, and withdrawal symptoms.
Dooley, J. M.; Gordon, K. E.; Wood, E. P.; Brna, P. M.; MacSween, J.; Fraser, A.
In adults, caffeine has been shown to enhance the effectiveness of most analgesics, including ibuprofen. This double-blind cross-over pilot study evaluated the effect of ibuprofen and caffeine compared with ibuprofen and placebo in 12 children with headaches. Patients completed diaries for both headaches. Outcome measures included a five-faces severity scale, a measure of clinical disability, and a scale of pain severity. Comparison of the cumulative response scores revealed a trend toward a greater response to ibuprofen-caffeine treatment of headaches (P = 0.14, P = 0.09, and P = 0.07 for the three measures, respectively). Further larger studies are needed to confirm this effect and to identify potential responders.
Bendlin, B. B.; Trouard, T. P.; Ryan, L.
Caffeine ingestion results in increased brain cell metabolism (Nehlig et al. [1992] Brain Res Brain Res Rev 17:139-170) and decreased cerebral blood flow (Field et al. [2003] Radiology 227:129-135; Mulderink et al. [2002] Neuroimage 15:37-44). The current study investigated the effect of caffeine in a word stem completion task using only novel word stems (no repeated stimuli). Resting perfusion was measured with arterial spin labeled perfusion MRI, along with blood oxygenation level-dependent (BOLD) signal before and after ingestion of regular coffee, decaffeinated coffee, and water. Based on previous research (Laurienti et al. [2002] Neuroimage 17:751-757; Mulderink et al. [2002] Neuroimage 15:37-44), we hypothesized that caffeine would result in increased BOLD signal intensity and extent of BOLD activation. As expected, caffeine resulted in a significant decrease in cerebral perfusion. However, both the control and caffeine groups showed an increase in BOLD signal amplitude across two sets of novel word stems. Additionally, the control group showed a 50% reduction in the extent of BOLD activation, while the caffeine group showed no change in activation extent. Neither group showed changes in BOLD baseline signal over time, which had been suggested to mediate caffeine-related BOLD signal changes. The results suggest that caffeine may attenuate general task practice effects that have been described in recent functional MRI studies of word stem completion (Buckner et al. [2000] Brain 123:620-640).
McLellan, T. M.; Kamimori, G. H.; Voss, D. M.; Tate, C.; Smith, S. J.
This study examined caffeine (CAF) effects on physical performance and vigilance during 4 d and 3 nights of sustained operations in Special Forces personnel. METHODS: There were 20 soldiers (28.6 +/- 4.7 yr, 177.6 +/- 7.5 cm, 81.2 +/- 8.0 kg) who were divided equally into placebo (PLAC) and CAF groups. A 4-km run that included three obstacles (OBST) was completed each morning with the performance on Day 2 representing control (CON) after familiarization on Day 1 and an 8-h sleep. From 01:30 to 06:15 of Days 3-5, soldiers performed two 2-h vigilance (VIG) sessions in the field. PLAC or 200 mg of CAF was administered at 21:45 of Days 2-4 and at 01:00, 03:45, and approximately 07:00 on Days 3-5. The run commenced within 30 min of the final dose. Soldiers were provided a 4-h sleep period from 13:30-17:30 during Days 3 and 4. RESULTS: VIC during Days 3-5 was greater for CAF vs. PLAC and not different from CON. Total run time was faster for CAF (29.7 +/- 2.0 min) compared with PLAC (30.7 +/- 2.9 min) on Day 3 due to faster completion of OBST (8.7 +/- 0.7 min vs. 9.2 +/- 1.0 min for CAF and PLAC, respectively). Thereafter, run times decreased for both groups on Days 4 and 5 compared with CON due primarily to an increased pace between OBST. CONCLUSIONS: it was concluded that CAF maintained both vigilance and physical performance during sustained operations that require periods of overnight wakefulness and restricted opportunities for daytime sleep.
Source : Aviat.Space Environ Med 2007 vol.78 (9), pp 871 - 877
Astorino, T. A.; Rohmann, R. L.; Firth, K.; Kelly, S.
Caffeine (CAF) exerts a pressor effect both at rest and during exercise, as blood pressure is higher than with placebo. However, the effect of acute CAF ingestion combined with intense resistance training on cardiovascular function is unknown. The primary aim of the study was to examine changes in cardiovascular function after completion of fatiguing bench-press and leg-press exercise after CAF or placebo ingestion. 22 resistance-trained men ingested CAF (6 mg/kg) or placebo 1 h preexercise in a randomized, double-blind crossover design. They refrained from CAF intake and strenuous exercise 48 and 24 h pretrial, respectively. Heart rate and blood pressure were measured preexercise. After a standardized warm-up, 1-repetition-max. (1-RM) on the barbell bench press and leg press was tested. When it had been determined, a load equivalent to 60% of 1-RM was placed on the bar, and the subject completed repetitions to failure. Measurements of heart rate and blood pressure were immediately completed, and mean arterial pressure and rate-pressure product were calculated. Results showed significant (P < 0.05) increases in heart rate (+10 beats/min), systolic blood pressure (+ 8-10 mmHg), and rate-pressure product with acute CAF ingestion versus placebo. No change (P > 0.05) in diastolic blood pressure across time or treatment was shown. It is suggested that to prevent elevated blood pressure and potential enhanced risk of heart disease, CAF intake should be monitored in at-risk men who participate in resistance training.
Borre, Y.; Chandrashekar, S.; Dougan, J. D.; Heidenreich, B. A.; Farmer-Dougan, V.
Changes in the sensitivity of response distributions to changes in reward distribution (reinforcer distribution sensitivity) were examined when rats were exposed to low and moderate doses of caffeine, ephedrine, and caffeine-ephedrine combinations. The data show significant decreases in sensitivity in response distributions to changes in reward schedule values during exposure to caffeine and ephedrine/caffeine combinations, whereas ephedrine alone resulted in overmatching comparable with baseline and NaCl conditions. Rats treated either with 3.0-mg/kg or 10.0-mg/kg doses of caffeine and all combinations of ephedrine at doses of 1.8 or 5.6 mg/kg with caffeine at 3.0 or 10.0 mg/kg showed reduced sensitivity in response distributions to differences in reinforcement schedule ratios. In contrast, when rats were exposed to ephedrine at 1.8 or 5.6 mg/kg, they maintained or increased the degree of overmatching. Although reinforcer distribution sensitivity was altered, drug exposure did not significantly affect the absolute rates of responding. Bias varied after exposure to caffeine, ephedrine, and their combinations, but not systematically. Finally, whereas the estimates of goodness of fit (r) to the matching equation showed some decreases during drug exposure, these were neither statistically significant nor correlated with drug dose. These results suggest differential effects of ephedrine and caffeine on the sensitivity of response distributions to changes in reinforcement ratio distributions, with deleterious effects of caffeine and ephedrine/caffeine combinations.
Hu, G.; Jousilahti, P.; Nissinen, A.; Bidel, S.; Antikainen, R.; Tuomilehto, J.Only 2 prospective studies have previously investigated the association between coffee consumption and incident hypertension, and the findings are equivocal. OBJECTIVE: The objective was to determine the relation between coffee consumption and the incidence of antihypertensive drug treatment. DESIGN: We prospectively followed 24 710 Finnish subjects aged 25-64 y without a history of antihypertensive drug treatment, coronary heart disease, or stroke at baseline. Daily coffee consumption was assessed by questionnaires. RESULTS: During a mean follow-up period of 13.2 y, 2505 participants started antihypertensive drug treatment. The multivariate-adjusted (age, sex, study year, education, leisure-time physical activity, smoking, body mass index, high total cholesterol, history of diabetes, and alcohol, tea, fruit, vegetable, sausage, and bread consumption) hazard ratios for antihypertensive drug treatment associated with the amount of coffee consumed daily (0-1, 2-3, 4-5, 6-7, or >or=8 cups) were 1.00, 1.29 (95% CI: 1.09, 1.54), 1.26 (95% CI: 1.06, 1.49), 1.24 (95% CI: 1.04, 1.48), and 1.14 (95% CI: 0.94, 1.37) (P for trend = 0.024), respectively. This trend became marginally significant after additional adjustment for baseline systolic blood pressure (P for trend = 0.077). CONCLUSIONS: The results indicate that coffee drinking seems to increase the risk of antihypertensive drug treatment, and this risk was higher in subjects with low-to-moderate coffee intakes; however, there was no significantly increased trend in drinkers of approximately 1 cup (100 mL)/d or >or=8 cups/d.
Voutilainen, S.; Tuomainen, T. P.; Mursu, J.; Salonen, J. T.
Background: The long-term longitudinal evidence for a relation between coffee intake and hypertension is relatively scarce. Objective: The objective was to assess whether coffee intake is associated with the incidence of hypertension. Design: This study was conducted on a cohort of 2985 men and 3383 women who had a baseline visit and follow-up visits after 6 and 11 y. Baseline coffee intake was ascertained with questionnaires and categorized into 0, >0–3, >3–6, and >6 cups/d. Hypertension was defined as a mean systolic blood pressure (SBP) 140 mm Hg over both follow-up measurements, a mean diastolic blood pressure (DBP) 90 mm Hg over both follow-up measurements, or the use of antihypertensive medication at any follow-up measurement. Results: Coffee abstainers at baseline had a lower risk of hypertension than did those with a coffee intake of >0–3 cups/d [odds ratio (OR): 0.54; 95% CI: 0.31, 0.92]. Women who drank >6 cups/d had a lower risk than did women who drank >0–3 cups/d (OR: 0.67; 95% CI: 0.46, 0.98). Subjects aged 39 y at baseline had 0.35 mm Hg (95% CI: –0.59, –0.11 mm Hg) lower SBP per cup intake/d and 0.11 mm Hg lower DBP (95% CI: –0.26, 0.03 mm Hg) than did those aged <39 y at baseline, although the difference in DBP was not statistically significant.
Conclusions: Coffee abstinence is associated with a lower hypertension risk than is low coffee consumption. An inverse U-shaped relation between coffee intake and risk of hypertension was observed in the women.
Cameron, M. D.; Wen, B.; Roberts, A. G.; Atkins, W. M.; Patricia-Campbell, A.; Nelson, S. D.
Acetaminophen ( N-acetyl- p-aminophenol, APAP) is a commonly used analgesic/antipyretic. When oxidized by P450, a toxic APAP metabolite is generated. Human P450 3A4 was expressed in Escherichia coli , purified, and reconstituted using artificial liposomes. Oxidation of APAP by P450 3A4, as detected by the formation of its glutathione adduct, was found to exhibit negative homotropic cooperativity with a Hill coefficient of 0.7. In the presence of caffeine, the observed kinetics were close to classical Michaelis-Menten kinetics with a Hill coefficient approaching 1. In order to probe for a potential repositioning of APAP within the P450 3A4 pocket in the presence of caffeine, NMR T 1 paramagnetic relaxation techniques were used to calculate distances from the P450 3A4 heme iron to protons of APAP alone and in the presence of caffeine. Both APAP and caffeine were found to bind at the active site in proximity to the heme iron. When APAP was incubated with P450 3A4, the acetamido group of APAP was found to be closest to the heme iron consistent with the amide group of APAP weakly associating with the heme iron. The addition of caffeine disrupted the ability of APAP to coordinate with the heme iron of P450 3A4 and enhanced the rate of oxidation to its toxic metabolite.
Mandal, A.; Poddar, M. K.
The aim of this study was to investigate the effect of long-term consumption of caffeine in the development of Ehrlich ascites carcinoma (EAC) cells in adult female mice, 25-30 g, in relation to immune response. Mice were treated with caffeine (20 mgkg(-1) daily, p.o.) for 22-27 consecutive days or inoculated with EAC cells (5 x 10(6) cells/mL, i.p.), or both. Control mice, corresponding to experimental groups, were treated with corresponding vehicles under similar conditions. The lymphocyte viability, mitogen-induced proliferating activity, cytotoxicity and DNA fragmentation from blood, spleen and thymus of both control and experimental groups were measured as immune response parameters. An immune response index, corticosterone, was also measured in adrenals and plasma under similar conditions. Results showed that development of EAC cells caused immune suppression with a reduction of lymphocyte viability, cytotoxicity and proliferative activity and induction of DNA fragmentation in those tissues, as well as an increase in plasma corticosterone. Though long-term caffeine treatment (which resulted in tolerance to caffeine) alone did not alter significantly any of the immune response parameters studied, including corticosterone status (immune biomarker), the continuation of caffeine treatment during the development of EAC cells either restored or reduced the EAC cell-induced alteration in these parameters, including the HPA axis biomarker. These results suggest that long-term caffeine intake may inhibit or reverse the EAC cell-induced immune suppression.
Lev, E. I.; Arikan, M. E.; Vaduganathan, M.; Alviar, C. L.; Tellez, A.; Mathuria, N.; Builes, A.; Granada, J. F.; del Conde, I.; Kleiman, N. S.
Clopidogrel inhibits the platelet P2Y12 receptor, leading to increased intracellular cyclic AMP (cAMP) levels. Caffeine also causes a rise in platelet cAMP. We aimed to test the effect of acute caffeine administration on platelet inhibition by clopidogrel, in healthy volunteers and patients with coronary artery disease. METHODS: Cohort 1: 12 healthy subjects were enrolled in a 2-week crossover study. Blood samples were drawn at baseline, 2, 4, and 24 hours after 300 mg clopidogrel intake. At the first week, 6 subjects received caffeine (300 mg pill, equivalent to a medium sized coffee drink) 30 minutes after clopidogrel. At week 2, the other 6 subjects received caffeine. One month later the effect of caffeine alone was tested. Platelet function was evaluated by aggregation in response to 5, 10, and 20 micromol/L adenosine diphosphate, 1 microg/mL collagen, and flow cytometric determination of P-selectin expression, PAC-1 binding, and vasodilator-stimulated phosphoprotein phosphorylation. Cohort 2: 40 patients with coronary artery disease receiving aspirin and clopidogrel (75 mg daily) for > or = 1 week were tested at baseline and 2.5 hours after caffeine (300 mg). RESULTS: In cohort 1 (crossover study), caffeine was associated with lower adenosine diphosphate-induced aggregation at 4 hours, lower activation markers at 2 hours, and lower vasodilator-stimulated phosphoprotein phosphorylation at 4 hours after clopidogrel. Caffeine alone had no effect on the assessed platelet surface biomarkers. In cohort 2, caffeine administration was associated with lower platelet activation markers (P-selectin, PAC-1 binding), without significant effect on aggregation. CONCLUSIONS: Acute caffeine administration after clopidogrel loading appears to be associated with enhanced platelet inhibition 2 to 4 hours after clopidogrel intake. The mechanism probably involves synergistic increase in cAMP levels.
Lohi, J. J.; Huttunen, K. H.; Lahtinen, T. M.; Kilpelainen, A. A.; Muhli, A. A.; Leino, T. K.
Caffeine has been suggested to act as a counter measure against fatigue in military operations. In this randomized, double-blind, placebo-controlled study, the effect of caffeine on simulator flight performance was examined in 13 military pilots during 37 hours of sleep deprivation. Each subject performed a flight mission in simulator four times. The subjects received either a placebo (six subjects) or 200 mg of caffeine (seven subjects) 1 hour before the simulated flights. A moderate 200 mg intake of caffeine was associated with higher axillary temperatures, but it did not affect subjectively assessed sleepiness. Flight performance was similar in both groups during the four rounds flown under sleep deprivation. However, subjective evaluation of overall flight performance in the caffeine group tended to be too optimistic, indicating a potential flight safety problem. Based on our results, we do not recommend using caffeine pills in military flight operations.
Goya, L.; Delgado-Andrade, C.; Rufian-Henares, J. A.; Bravo, L.; Morales, F. J.
Soluble high-molecular weight fraction (named melanoidin) from coffee brew was isolated by ultrafiltration, subsequently digested by simulating a gastric plus pancreatic digestive condition and partly characterized by CZE, gel-filtration and browning. The objective of the present study was to investigate the potential protective effect of the coffee melanoidin submitted to gastrointestinal digestion on cell viability (lactate dehydrogenase leakage) and redox status of cultured human hepatoma HepG2 cells submitted to oxidative stress induced by tert-butylhydroperoxide (t-BOOH). Concentration of reduced glutathione (GSH) and malondialdehyde (MDA), generation of reactive oxygen species (ROS) and activity of antioxidant enzymes glutathione peroxidase (GPx) and reductase (GR) were used as markers of cellular oxidative status. Pretreatment of cultured HepG2 cells with 0.5-10 microg/mL digested coffee melanoidins (DCM) for 2 or 20 h completely prevented the increase in cell damage and GR and partly prevented the decrease of GSH and the increase of MDA and GPx evoked by t-BOOH in HepG2 cells. In contrast, increased ROS generation induced by t-BOOH was not prevented when cells were pretreated with DCM. The results show that treatment of HepG2 cells with concentrations of DCM within the expected physiological range confers the cells a significant protection against an oxidative insult.
Tieges, Z.; Snel, J.; Kok, A.; Plat, N.; Ridderinkhof, R.
Effects of caffeine on task switching were studied using ERPs in a cued task-switch paradigm. The need for advance preparation was manipulated by varying the number of task-set aspects that required switching. In a double-blind, within-subjects experiment, caffeine reduced shift costs compared to placebo. ERPs revealed a negative deflection developing within the preparatory interval, which was larger for shift than for repeat trials. Caffeine increased this shift-induced difference. Furthermore, shift costs increased as a function of the number of task-set features to be switched, but this pattern was not modulated by caffeine. The results suggest that caffeine improves task-switching performance by increasing general effects on task switching, related to task-nonspecific (rather than task-specific) anticipatory processes. Caffeine\'s actions may be mediated by dopaminergic changes in the striatum or anterior cingulate cortex.
Shearer, J.; Sellars, E. A.; Farah, A.; Graham, T. E.; Wasserman, D. H.
Epidemiological studies indicate that regular coffee consumption reduces the risk of developing type 2 diabetes. Despite these findings, the biological mechanisms by which coffee consumption exerts these effects are unknown. The aim of this study was twofold: to develop a rat model that would further delineate the effects of regular coffee consumption on glucose kinetics, and to determine whether coffee, with or without caffeine, alters the actions of insulin on glucose kinetics in vivo. Male Sprague-Dawley rats were fed a high-fat diet for 4 weeks in combination with one of the following: (i) drinking water as placebo (PL), (ii) decaffeinated coffee (2 g/100 mL) (DC), or (iii) alkaloid caffeine (20 mg/100 mL) added to decaffeinated coffee (2 g/100 mL) (CAF). Catheters were chronically implanted in a carotid artery and jugular vein for sampling and infusions, respectively. Recovered animals (5 days postoperative) were fasted for 5 h before hyperinsulinemic-euglycemic clamps (2 mU.kg-1.min-1). Glucose was clamped at 6 mmol/L and isotopes (2-deoxy-[14C]glucose and [3-3H]glucose) were administered to obtain indices of whole-body and tissue-specific glucose kinetics. Glucose infusion rates and measures of whole-body metabolic clearance were greater in DC than in PL or CAF, indicating increased whole-body insulin sensitivity. As the only difference between DC and CAF was the addition of alkaloid caffeine, it can be concluded that caffeine antagonizes the beneficial effects of DC. Given these findings, decaffeinated coffee may represent a nutritional means of combating insulin resistance.
Source : Can J Physiol Pharmacol 2007 vol.85 (8), pp 823 - 830
Dekker, M. J.; Gusba, J. E.; Robinson, L. E.; Graham, T. E.
Acute caffeine ingestion increases serum non-esterified fatty acids (NEFA) and plasma adrenaline and decreases insulin sensitivity. Although frequently suggested, it is not known if a tolerance to these alterations in glucose homeostasis is developed in habitual caffeine consumers. This study aimed to determine whether acute caffeine ingestion continued to alter insulin, glucose, NEFA and adrenaline during an oral glucose tolerance test (OGTT) following 14 days of caffeine consumption. 12 caffeine-naïve young males underwent 4 OGTT over a 4-wk period. Subjects ingested a gelatin-filled placebo (PLA) capsule on the 1st trial day and 5 mg caffeine/kg body wt. on the remaining 3 trial days (day 0, day 7, day 14) before a 2 h OGTT. Following day 0 and day 7, subjects were given 6 dosages of 5 mg caffeine/kg to consume per day between trials. Serum insulin and blood glucose area under the curve (AUC) were significantly elevated (P < 0.05) vs. PLA on day 0 (36 and 103%, respectively) and were not different from PLA on day 7. On day 14, insulin AUC was 29% greater than PLA (P < 0.05), and glucose was greater (P < 0.05) during the 1st hour, although the 50% elevation in glucose AUC was not different from PLA. Before the OGTT, caffeine resulted in greater (P < 0.05) serum NEFA and plasma adrenaline concn. in all 3 caffeine trials, but both NEFA and adrenaline concn. were decreased (P < 0.05) on day 14 vs. day 0. Although 14 days of caffeine consumption by previously caffeine-naive subjects reduced its impact on glucose homeostasis, carbohydrate metabolism remained disrupted.
Kyung, Jin Lee; Jea, Ho Choi; Hye, Gwang Jeong
The hepatoprotective effects of kahweol and cafestol, coffee-specific diterpenes, on the carbon tetrachloride (CCl4)-induced liver damage as well as the possible mechanisms involved in these protections were investigated. Pretreatment with kahweol and cafestol prior to the administration of CCl4 significantly prevented the increase in the serum levels of hepatic enzyme markers (alanine aminotransferase and aspartate aminotransferase) and reduced oxidative stress, such as reduced glutathione content and lipid peroxidation, in the liver in a dose-dependent manner. The histopathological evaluation of the livers also revealed that kahweol and cafestol reduced the incidence of liver lesions induced by CCl4. Treatment of the mice with kahweol and cafestol also resulted in a significant decrease in the cytochrome P450 2E1 (CYP2E1), the major isozyme involved in CCl4 bioactivation, specific enzyme activities, such as p-nitrophenol and aniline hydroxylation. Kahweol and cafestol exhibited antioxidant effects on FeCl2-ascorbate induced lipid peroxidation in a mouse liver homogenate, and on superoxide radical scavenging activity. These results suggest that the protective effects of kahweol and cafestol against the CCl4-induced hepatotoxicity possibly involve mechanisms related to their ability to block the CYP2E1-mediated CCl4 bioactivation and free radical scavenging effects.
Kuwayama, K.; Inoue, H.; Kanamori, T.; Tsujikawa, K.; Miyaguchi, H.; Iwata, Y.; Miyauchi, S.; Kamo, N.; Kishi, T.
Amphetamine-type stimulants (ATSs) are often abused orally in the form of tablets for recreational purposes. The ATS tablets contain one or more active ingredients such as 3,4-methylenedioxymethamphetamine (MDMA), methamphetamine (MA), ketamine (KA), and caffeine (CF). The aim of this work is to determine whether such components in tablets interact with each other in intestinal absorption. The interactions between MDMA, MA, KA, and CF in the uptake and permeation by human intestinal epithelial Caco-2 cell line were investigated in monolayer cultures. MDMA, MA, and KA mutually inhibited the uptakes by Caco-2 cells. The inhibition of MA uptake by KA was the greatest of all combinations (72.6% inhibition). Similarly, MDMA, MA, and KA mutually inhibited the permeation from the apical to the basolateral side through Caco-2 cells. Although CF did not affect the uptakes of MDMA, MA, and KA, CF enhanced the permeation of MDMA in comparison to MDMA alone. In addition, the interaction of MA with KA and that of MDMA with CF in intestinal absorption were investigated by oral administration to rats. The area under the plasma concentration-time curve of MA significantly decreased by co-administration with KA in comparison to MA alone, while that of MDMA significantly increased by co-administration with CF in comparison to MDMA alone. The results in rats were similar to those in Caco-2 cells. These findings suggest that the intestinal absorption of similar compounds with amine moieties such as MDMA, MA, and KA are mediated by a common transport system, and that CF affects the absorption of MDMA in a different way from the transport system. In human, intakes of ATS tablets mixed with such components might result in similar interactions in intestinal absorption to those in Caco-2 cells and rats.
Browne, M. L.; Bell, E. M.; Druschel, C. M.; Gensburg, L. J.; Mitchell, A. A.; Lin, A. E.; Romitti, P. A.;
Correa, A.
The physiologic effects and common use of caffeine during pregnancy call for examination of maternal caffeine consumption and risk of birth defects. Epidemiologic studies have yielded mixed results, but such studies have grouped etiologically different defects and have not evaluated effect modification. METHODS: The large sample size and precise case classification of the National Birth Defects Prevention Study allowed us to examine caffeine consumption and specific cardiovascular malformation (CVM) case groups. We studied consumption of caffeinated coffee, tea, soda, and chocolate to estimate total caffeine intake and separately examined exposure to each caffeinated beverage. Smoking, alcohol, vasoactive medications, folic acid supplement use, and infant gender were evaluated for effect modification. Maternal interview reports for 4,196 CVM case infants overall and 3,957 control infants were analyzed. RESULTS: We did not identify any significant positive associations between maternal caffeine consumption and CVMs. For tetralogy of Fallot, nonsignificant elevations in risk were observed for moderate (but not high) caffeine intake overall and among nonsmokers (ORs of 1.3 to 1.5). Risk estimates for both smoking and consuming caffeine were less than the sum of the excess risks for each exposure. We observed an inverse trend between coffee intake and risk of atrial septal defect; however, this single significant pattern of association might have been a chance finding. CONCLUSIONS: Our study found no evidence for an appreciable teratogenic effect of caffeine with regard to CVMs.
Source : Birth Defects Res A Clin Mol Teratol 2007 vol.79 (7), pp 533 - 543
Alvira, D.; Yeste-Velasco, M.; Folch, J.; Casadesus, G.; Smith, M. A.; Pallas, M.; Camins, A.
The aim of the present study was to evaluate the neuroprotective effects of caffeine, an inhibitor of ataxia telangiectasia mutated (ATM) enzyme and an antagonist of adenosine receptors, in two models of apoptosis in cerebellar granule neurons (CGNs): the inhibition of mitochondrial complex I by the neurotoxin MPP(+) and serum and potassium deprivation. We used cerebellar granule neurons because of low glial contamination. Cell viability was measured by the MTT method, and apoptosis was evaluated by assessing DNA fragmentation with flow cytometry or quantification of nuclear condensation. Our data indicate that the neuroprotective effects of caffeine in the MPP+ model of apoptosis are mediated through activation of the ATM/p53 pathway. In addition, caffeine decreased the expression of cyclin D and the transcription factor E2F-1, a regulator of apoptosis in neurons. Caffeine-mediated neuroprotection was not mediated through blockade of adenosine receptors because DPCPX and CGS-15943, two antagonists of these receptors, failed to attenuate apoptosis produced by MPP+ treatment. In addition, caffeine did not exert neuroprotective effects after serum and potassium withdrawal, a p53-independent model of apoptosis. Taken together, our findings indicate that DNA damage/ATM activation is a key component of MPP+-induced apoptosis in CGNs through activation of p53 and reentry into the cell cycle, specifically expression of the transcription factor E2F-1.
Rengelshausen, J.; Goggelmann, C.; Burhenne, J.; Riedel, K. D.; Mikus, G.; Walter-Sack, I.; Haefeli, W. E.
Urinary caffeine metabolic ratios used to quantify the activity of numerous drug-metabolizing enzymes are an established component of cocktail approaches for metabolic phenotyping. Because in vitro evidence suggests that 1-methylxanthine (1-MX), a major caffeine metabolite, is actively secreted into urine by organic anion transporters (hOATs), coadministration of renal hOAT inhibitors like probenecid may impair these procedures. METHODS: In a randomized, placebo-controlled, double-blind crossover design, single oral doses of 300 mg caffeine with oral coadministration of placebo or 500 mg probenecid 3 times daily for 2 days were administered to 7 healthy men. The plasma and urine concentrations of caffeine and its major metabolites 1,7-dimethylxanthine (1,7-DMX) and 1-MX were determined by high-performance liquid chromatography. RESULTS: Coadministration of probenecid resulted in a 34% reduction of the renal clearance of 1-MX (mean +/- SD 190 +/- 42 versus 290 +/- 83 ml min(-1), 95% CI on difference 0.2, 200, p = 0.04) with a 41% reduction in its estimated non-glomerular clearance. The renal clearances of caffeine and 1,7-DMX and the area under the plasma concentrationtime curves of all substances were not significantly changed. CONCLUSIONS: 1-MX undergoes renal tubular secretion which is substantially reduced by probenecid, possibly due to inhibition of renal hOATs. This inhibition may explain the influence of probenecid on urinary caffeine metabolic ratios and, thus, its impact on the assessment of enzyme activities. It also suggests that 1-MX might serve as a model substrate for the renal tubular transport of organic anions.
Source : Int J Clin Pharmacol Ther 2007 vol.45 (8), pp 431 - 437
Cadden, I. S.; Partovi, N.; Yoshida, E. M.
Coffee is consumed by 50 percent of Americans every day. After oil, coffee is the second most valuable commodity in the world. In recent years a number of studies have suggested potential health risks associated with coffee consumption; however, the results are controversial. Whilst coffee has been reported to increase cardiovascular risk factors, other investigators have demonstrated its protective effects on diseases ranging from type 2 diabetes to Parkinson\'s disease. A number of investigators have focused their attention on the relationship between the consumption of coffee and liver disease. AIM: To examine the published literature to date in an attempt to establish the presence of an hepatoprotective effect of coffee. METHODS: Using PubMed, we identified published studies and review articles relating to the effect of coffee consumption on diseases of the liver. CONCLUSION: A number of studies have reported the beneficial effects of coffee on abnormal liver biochemistry, cirrhosis and hepatocellular carcinoma. At the present time the mechanism of this effect remains unclear as does the \'\'dose\'\' required to achieve these benefits.
Giovannetti, T.; Schwartz, M. F.; Buxbaum, L. J.
Errors in everyday activities pose significant consequences for individuals with mild cognitive deficits. However, there are few performance-based methods available to study action in these populations; the Coffee Challenge (CC) was designed for this purpose. Experiment 1 examined CC performance in healthy participants across 10 practice trials. Analyses showed evidence for routinization after 10 trials. In Experiment 2, CC performance was disrupted by dividing attention. Errors increased significantly, but performance was not qualitatively different from baseline. The results shed light on action impairments in patient populations and validate the CC as a promising new tool for future studies.
Source : J Clin Exp Neuropsychol 2007 vol.29 (7), pp 690 - 705
Higgins, G. A.; Grzelak, M. E.; Pond, A. J.; Cohen-Williams, M. E.; Hodgson, R. A.; Varty, G. B.
Caffeine produces effects on cognitive function particularly relating to aspects of attention such as reaction time. Considering the plasma exposure levels following regular caffeine intake, and the affinity of caffeine for known protein targets, these effects are likely mediated by either the adenosine A(1) or A(2A) receptor. In the present studies, two rat strains [Long-Evans (LE) and CD] were trained to asymptote performance in a test of selective attention, the 5-choice serial reaction time task (5-CSRTT). Next, the effects of caffeine were compared to the selective A(2A) antagonists, SCH 412348 and KW-6002(Istradefylline), and the A(1) antagonist, DPCPX. Further studies compared the psychostimulant effects of each drug. Finally, we tested the A(2A) agonist, CGS-21680, on 5-CSRTT performance and given the antipsychotic potential of this drug class, studied the interaction between CGS-21680 and amphetamine in this task. Caffeine (3-10mg/kg IP) increased reaction time in both LE and CD rats, with no effect on accuracy, an effect replicated by SCH 412348 (0.1-1mg/kg PO) and KW-6002 (1-3mg/kg PO), but not DPCPX (3-30mg/kg PO). At least with SCH 412348, these effects were at doses that were not overtly psychostimulant. In contrast, CGS-21680 (0.03-0.3mg/kg IP) slowed reaction speed and increased omissions. Interestingly, at a comparatively low dose of 0.03mg/kg, CGS-21680 attenuated the increased premature responding produced by amphetamine (1mg/kg IP). The present results suggest that the attention-enhancing effects of caffeine are mediated through A(2A) receptor blockade, and selective A(2A) receptor antagonists may have potential as therapies for attention-related disorders. Furthermore, the improvement in response control in amphetamine-treated rats following CGS-21680 pretreatment supports the view that A(2A) agonists have potential as novel antipsychotics.
Various authors
The following papers were presented at the DG Sanco/CIAA workshops on \'acrylamide\' and \'furan in food\', held in March and May 2006: \'Update on the progress in acrylamide and furan research\', by R.H. Stadler and E. Anklam; \'EU acrylamide workshop\', by D. Lineback; \'European Union database of acrylamide levels in food: update and critical review of data collection\', by T. Wenzl and E. Anklam; \'Occurrence of acrylamide in selected foods and mitigation options\', by T.M. Amrein, L. Andres, F. Escher and R. Amado; \'Genetic and agronomic approaches to decreasing acrylamide precursors in crop plants\', by N.G. Halford, N. Muttucumaru, T.Y. Curtis and M.A.J. Parry; \'Acrylamide in fried and roasted potato products: a review on progress in mitigation\', by R.J. Foot, N.U. Haase, K. Grob and P. Gonde; \'Acrylamide in cereal and cereal products: a review on progress in level reduction\', by E.J.M. Konings, P. Ashby, C.G. Hamlet and G.A.K. Thompson; \'Acrylamide in coffee: review of progress in analysis, formation and level reduction\', by H. Guenther, E. Anklam, T. Wenzl and R.H. Stadler; \'Options for legal measures to reduce acrylamide contents in the most relevant foods\', by K. Grob; \'The German minimization concept for acrylamide\', by A. Gobel and A. Kliemant; \'Furan in food: headspace method and product survey\', by O. Zoller, F. Sager and H. Reinhard; \'Factors affecting the analysis of furan in heated foods\', by C. Crews, S. Hasnip, D.P.T. Roberts and L. Castle; \'Data requirements for risk assessment of furan in food\', by C.W. Heppner and J.R. Schlatter; \'Formation of furan and methylfuran from ascorbic acid in model systems and food\', by A. Limacher, J. Kerler, B. Conde-Petit and I. Blank; and \'Potential of furan formation in hazelnuts during heat treatment\', by H.Z. Senyuva and V. Gokmen.
Source : Food Add Contam 2007 vol.24 (9), supplement "Update on the progress in
acrylamide and furan" (not available on line
Guenther, H.; Anklam, E.; Wenzl, T.; Stadler, R. H.
This paper summarizes the progress made in understanding the formation of acrylamide in coffee, as well as potential reduction strategies, as presented during the joint CIAA/EC workshop on acrylamide, held in Brussels in March 2006. Currently, there are no concrete measures to reduce acrylamide concn. in roast and ground coffee without appreciably changing the sensory properties of the product. Certain approaches, such as steam roasting, have been tried on a laboratory scale, albeit without affording a significant reduction. It is suggested that more work on the mechanisms governing the loss of Acrylamide during storage of roast and ground coffee is warranted, and studies in this direction have been initiated. Finally, risk/benefit analysis must be addressed in a complex food such as coffee, known to harbour numerous health beneficial or chemoprotective compounds with antioxidative and antimutagenic properties.
Anon.
This atmospheric pressure drying method for determination of mass loss on drying of coffee extract corresponds to that specified in German Standard DIN 10764-4, issued in March 2007.
Source : Amtliche Sammlung von Untersuchungsverfahren nach Paragraph 64 LMBG.2007 vol.L pp 46 -
49 (not available on line)
Anon.
This vacuum drying method for determination of mass loss on drying of coffee extract corresponds to that specified in German Standard DIN 10764-2, issued in March 2007.
Source : Amtliche Sammlung von Untersuchungsverfahren nach Paragraph 64 LMBG.2007 vol.L pp 46 -
48 (not available on line)
Anon.
This method for determination of mass loss on drying of raw coffee at 105°C corresponds to that specified in German Standard DIN ISO 6673, issued in March 2007.
Source : Amtliche Sammlung von Untersuchungsverfahren nach Paragraph 64 LMBG 2007 vol.L, pp 46 (not available on line)
Dorri, Y.; Sabeghi, M.; Kurien, B. T.
Smell and its mechanism has been of interest to scientists for many years. Smell, not only provides a sensual pleasure of food and perfumes for humans but also reminds us of past memories, thoughts, locations and finally warns of dangers such as fire. One of the uses of coffee beans is on perfume counters, enabling people to distinguish between perfume fragrances. We hypothesize that coffee can be also used to refresh olfactory receptors after cooking, since people usually experience loss of appetite after cooking. We have experienced an increase in appetite, after cooking, by smelling coffee beans. This is probably due to the detachment of food odourants from olfactory receptors by the coffee odourant molecules. We also think that coffee smell could be used in animal research studies, to keep animals healthy by stimulating their appetite. In a recent study, 28 different odourants have been identified from coffee. One or more of these odourants may have strong binding affinity to olfactory receptors which results in detachment of other odourants from the receptors. The high vibration intensity from coffee odourant molecules may cause the detachment of food odourant from olfactory receptors. Another hypothesis might be the unique structure of these coffee odourants. Studies need to be done to investigate the effect of coffee smell on salivary flow and appetite in animals and humans.
Lopez-Galilea, I.; De Pena, M. P.; Cid, C.
Relationships between volatile and nonvolatile compounds and the antioxidant capacity of coffee brews prepared from commercial conventional and torrefacto roasted coffees, employing commonly used doses and prepared by four brewing procedures (filter, plunger, mocha, and espresso machine) were assessed. Significant correlations between volatile Maillard reaction products and antioxidant capacity (measured by both 2,2-diphenyl-1-picrylhydrazyl radical and redox potential methods) were not observed. Highly positive correlations between browned compounds and caffeine with both antioxidant capacity parameters were reported. Principal component analysis allowed coffee brews separation according to coffee roasting processes (PC1) and brewing procedures (PC2), showing that in all cases coffee brews from torrefacto roasted coffee were more antioxidant that those extracted from conventional ones; also, coffee brews extracted by an espresso machine were more antioxidant than those extracted by mocha, plunger, and filter machines.
Source : J Agric Food Chem 2007 vol.55 (15 ), pp 6110 - 6117
Thomas, J. B.; Sharpless, K. E.; Mitvalsky, S.; Roman, M.; Yen, J.; Satterfield, M. B.
Caffeine and its derivatives can cause adverse physiological effects, particularly when taken in combination with other stimulants, such as ephedra. In this study, the caffeine, theobromine and theophylline contents of two ephedra-containing standard reference materials (SRM 3243 Ephedra-Containing Solid Oral Dosage Form; and SRM 3244 Ephedra-Containing Protein Powder) were determined by the National Institute of Standards and Technology and a collaborating laboratory using three independent methods (reversed-phase liquid chromatography with absorbance or tandem mass spectrometry detection). The Standard Reference Materials, which are part of a series that provide concentration values for multiple components in dietary supplements, are intended for method validation and quality control of dietary supplements.
Nogueira, T.; do-Lago, C. L.
A method based on the formation of pi-complexes with chlorogenate-like species was proposed for the determination of caffeine in regular (nondecaffeinated) and decaffeinated coffee. Both caffeate and 3,4-dimethoxycinnamate were able to transform caffeine - a neutral species in aqueous solutions - into an anionic species. The usage of 3,4-dimethoxycinnamate in the running electrolyte is advantageous, because of its greater chemical stability and the improved resolution of the peaks of caffeine, theobromine, and theophylline. Negative peaks were registered with a capacitively coupled contactless conductivity detector when solutions of these alkylxanthines were analyzed with a BGE composed of 20 mmol/L 3,4-dimethoxycinnamic acid and pH adjusted to 8.5 with Tris. This behavior was expected, because the complex is larger and thus should move slower than the free anion. Caffeine was determined in ground and instant coffee with precision and accuracy that meet Brazilian norms about such products. The LOD was estimated as 33 mg/L, which corresponds to 0.8 and 0.3 mg of caffeine per gram of dry instant coffee and ground coffee, respectively. For the case of decaffeinated coffee, ten times preconcentration with dichloromethane was carried out to allow the quantitation of caffeine, which should not exceed the concentration of 1 mg/g in dry matter.
Grembecka, M.; Malinowska, E.; Szefer, P.
The concentrations of 14 elements (Ca, Mg, K, Na, P, Co, Mn, Fe, Cr, Ni, Zn, Cu, Cd, Pb) were determined in market coffee samples after dry mineralisation of both dry samples and infusions evaporated to dryness. The total metal contents were analysed by flame atomic absorption spectrometry (F-AAS) using deuterium-background correction. Phosphorus was determined in the form of phosphomolybdate by spectrophotometric method. Reliability of the procedure was checked by the analysis of the certified reference materials Tea (NCS DC 73351), Cabbage (IAEA-359) and Spinach leaves (NIST-1570). It was concluded, based on RDA calculated for essential metals, that coffee infusions are not an important source of bioelements in human diet. In the case of toxic elements Provisional Tolerable Weekly Intake (PTWI) was estimated and there is no health hazard associated with exposure to Cd and Pb via coffee consumption. Significant correlation coefficients (p<0.001, p<0.01 and p<0.05) were found between concentrations of some metals in coffee. Factor analysis and canonical analysis were applied to the data processing in order to characterise the market coffee samples. The 12 metals determined were considered as chemical descriptors of each sample. Based on the mineral composition, it was possible to differentiate chemometrically particular types of coffee distinguishing arabica from robusta, ground from instant coffee, and their infusions.
Almajano, M. P.; Carbo, R.; Delgardo, M. E.; Gordon, M. H.
Caffeic acid is a polyphenolic compound present in many foods including blueberries, apples and coffee. Its antioxidant and antimicrobial activity are of interest owing to the potential of caffeic acid as a natural food preservative. Previous studies have indicated that a combination of caffeic acid with bovine serum albumin (BSA) shows better antioxidant properties than either substance separately. In this study, the effects of pH on the antioxidant and antimicrobial activity of caffeic acid in different media and in the presence of BSA were investigated. The results indicated that the presence of BSA increased the antioxidant activity of caffeic acid. The antimicrobial activity of caffeic acid was found to be pH dependent, and was greater at pH values of 5 - 7 than at neutral pH values.
Jham, G. N.; Winkler, J. K.; Berhow, M. A.; Vaughn, S. F.
The adulteration of coffee with cereals, coffee twigs, etc. is apparently widespread in Brazil with corn being considered the most widely used. No adequate methods are available to detect such contamination in commercial coffee. A new method, based on high-performance liquid chromatography (HPLC) tocopherol determination was developed to detect coffee adulteration by corn. Percentages of alpha-, beta-, gamma-, and delta-tocopherol determined by HPLC in six coffee varieties were 29.0, 61.7, 3.3, and 6.0, respectively. Similar values were obtained in six popular coffee brands. The percentages of alpha-, gamma-, and delta-tocopherol in six corn samples were 3.6, 91.3, and 5.1, respectively. These differences could be applied to detect corn in a pure coffee sample intentionally contaminated with corn with the best result obtained with gamma-tocopherol. With this methodology, one coffee brand was apparently adulterated (8.9%), most likely with corn. Tocopherol fingerprinting offers the potential to detect adulteration.
Sobottka-Rolim-de-Moura, S. C.; Pimentel-Marconi-Germer, S.; Delgado-de-Almeida-Anjos, V.; Mori, E.-E. M.; Capparelli-Mattoso, L. H.; Firmino, A.; Fernandes-Nascimento, C. J.
An evaluation of the roasting process of pure arabica coffee was performed using a 22 factorial design with 5 levels. This design resulted in 11 samples, the independent variables being the internal temp. of the drum at the beginning (200-230°C) of the process and the roasting time (10-15 min). Samples were analysed with respect to their chemical characteristics (pH, acidity and contents of moisture, soluble solids, reducing sugars and caffeine), physical properties (density, roasting degree, reflectance and instrumentally measured colour (L* a* b*)) and sensory properties with principal component analysis using an electronic tongue. It was possible to obtain predictive models for the physical and chemical characteristics, as well as for the sensory characteristics of sweetness and bitterness, as a function of time and roasting degree temp. using response surface methodology. Correlating the physical and chemical results with the overall sensory quality, optimum roasting for pure arabica coffee was determined to occur at 215°C for 17.5 min.
Source : Brazilian J Food Technol 2007 vol.10 (1), pp 17 - 25 (not available on line)
Pellegrini, M.; Marchei, E.; Rossi, S.; Vagnarelli, F.; Durgbanshi, A.; Garcia-Algar, O.; Vall, O.; Pichini, S.
A procedure based on liquid chromatography/tandem mass spectrometry (LC/MS/MS) is described for the determination of nicotine and its principal metabolites cotinine, trans-3-hydroxycotinine and cotinine-Noxide, caffeine and arecoline in breast milk, using N-ethylnorcotinine as internal standard. Liquid/liquid extraction with chloroform/isopropanol (95:5, v/v) was used for nicotine, cotinine, trans-3-hydroxycotinine, cotinine-N-oxide and caffeine under neutral conditions and for arecoline under basic conditions. Chromatography was performed on a C(8) reversed-phase column using a gradient of 50 mM ammonium formate, pH 5.0, and acetonitrile as a mobile phase at a flow rate of 0.5 mL/min. Separated analytes were determined by electrospray ionization tandem mass spectrometry in the positive ion mode using multiple reaction monitoring. Limits of quantification were 5 microg/L for nicotine, cotinine, trans-3-hydroxycotinine, cotinine-N-oxide and caffeine, and 50 microg/L for arecoline using 1 mL human milk per assay. Calibration curves were linear over the calibration ranges for all the substances under investigation, with a minimum r(2) > 0.998. At three concentrations spanning the linear dynamic range of the assay, mean recoveries from breast milk ranged between 71.8 and 77.4% for different analytes. This method was applied to the analysis of analytes in human milk to assess substance exposure in breast-fed infants in relation to eventual clinical outcomes. This LC/MS/MS assay provides adequate sensitivity and performance characteristics for the simultaneous quantification of biomarkers of three of the drugs most commonly used worldwide (tobacco, caffeine and areca nut).
Source : Rapid Commun Mass Spectrom 2007 vol.21 (16), pp 2693 - 2703
Shrivas, K.; Wu, H. F.
A simple and rapid sample cleanup and preconcentration method for the quantitative determination of caffeine in one drop of beverages and foods by gas chromatography/mass spectrometry (GC/MS) has been proposed using drop-to-drop solvent microextraction (DDSME). The best optimum experimental conditions for DDSME were: chloroform as the extraction solvent, 5min extraction time, 0.5muL exposure volume of the extraction phase and no salt addition at room temperature. The optimized methodology exhibited good linearity between 0.05 and 5.0mug/mL with correlation coefficient of 0.980. The relative standard deviation (RSD) and limits of detection (LOD) of the DDSME/GC/MS method were 4.4% and 4.0ng/mL, respectively. Relative recovery of caffeine in beverages and foods were found to be 96.6- 101%, which showing good reliability of this method. This DDSME excludes the major disadvantages of conventional method of caffeine extraction, like large amount of organic solvent and sample consumption and long sample pre-treatment process. So, this approach proves that the DDSME/GC/MS technique can be applied as a simple, fast and feasible diagnosis tool for environmental, food and biological application for extremely small amount of real sample analysis .
Andrews, K. W.; Schweitzer, A.; Zhao, C.; Holden, J. M.; Roseland, J. M.; Brandt, M.; Dwyer, J. T.; Picciano, M. F.; Saldanha, L. G.; Fisher, K. D.; Yetley, E.; Betz, J. M.; Douglass, L.
As part of a study initiating the development of an analytically validated Dietary Supplement Ingredient Database (DSID) in the United States (US), a selection of dietary supplement products were analyzed for their caffeine content. Products sold as tablets, caplets, or capsules and listing at least one caffeine containing ingredient (including botanicals such as guarana, yerba mate, kola nut, and green tea extract) on the label were selected for analysis based on market share information. Two or three lots of each product were purchased and analyzed using high-pressure liquid chromatography (HPLC). Each analytical run included one or two National Institute of Standards and Technology (NIST) Standard Reference Materials (SRMs) and two products in duplicate. Caffeine intake per serving and per day was calculated using the maximum recommendations on each product label. Laboratory analysis for 53 products showed product means ranging from 1 to 829 mg caffeine/day. For products with a label amount for comparison (n = 28), 89% (n = 25) of the products had analytically based caffeine levels/day of between -16% and +16% of the claimed levels. Lot-to-lot variability (n = 2 or 3) for caffeine in most products (72%) was less than 10%.
Castillo, M.; Cortes, M. A.; Montesinos, L.
Validation trials on a HPLC method for determination of ochratoxin A in foods are reported. Trials were conducted on samples of cereals, dried fruit, coffee and spices. Results showed that precision, accuracy and quantification limit were in accordance with Spanish requirements.
Source : Alimentaria 2007 vol.382, pp 93 - 94 (not available on line)
Muscat, S.; Pelka, J.; Hegele, J.; Weigle, B.; Munch, G.; Pischetsrieder, M.
In this study, we investigated the immunomodulatory activity of coffee and Maillard reaction products on macrophages in vitro. Stimulation of macrophages with coffee, but not with raw coffee extract in PBS, led to a 13-fold increased nuclear NF-kappaB translocation. A Maillard reaction mixture (25 mM D-ibose/Llysine, 30 min at 120 degrees C) increased NF-kappaB translocation 18-fold (in PBS) or six-fold (in medium). MRPs also induced a two-fold increased NF-kappaB translocation in untransfected human embryonic kidney (HEK) cells as well as in HEK cells stably transfected with the receptor for advanced glycation endproducts (RAGE), indicating that the effect was not RAGE mediated. On the other hand, catalase totally abolished coffee- and MRP-induced NF-kappaB translocation. Consequently, up to 366 microM hydrogen peroxide was measured in the coffee preparation and Maillard mixtures used for cell stimulation. Stimulation of macrophages with MRPs did not lead to significantly increased IL-6 or NO release. Thus, it can be concluded that coffee and MRPs induce NF-kappaB translocation in macrophages via the generation of hydrogen peroxide.
Dash, S. S.; Gummadi, S. N.
In this study, the kinetics of degradation of caffeine and related methylxanthines by induced cells of Pseudomonas sp. was performed. The kinetics data showed that degradation of caffeine, theobromine, and 7-methylxanthine followed Michealis-Menten kinetics. The values of K (m) are low for caffeine and 7-methylxanthine and high for theobromine. Degradation of caffeine and theobromine was enhanced in the presence of NADH and NADPH, whereas the degradation of 7-methylxanthine was unaffected. Among the various metal ions tested, Fe(2+) was found to enhance the rate of degradation for all three substrates, whereas Zn(2+) and Cu(2+) inhibited the degradation of caffeine and theobromine but not 7-methylxanthine. The differences in kinetic parameters and cofactor requirement suggest the possibility of the involvement of more than one N-demethylases in the caffeine catabolic pathway in Pseudomonas sp. The induced cells can serve as effective biocatalysts for the development of biodecaffeination techniques.
Gniechwitz, D.; Reichardt, N.; Blaut, M.; Steinhart, H.; Bunzel, M.
Arabinogalactans and galactomannans from coffee beverages are part of the dietary fibre complex. Chemical structures and fermentability of soluble dietary fibre obtained from a standard filter coffee beverage (Coffea arabica, origin Colombia, medium roasted) by human intestinal bacteria were investigated. 1 cup (150 ml) of filter coffee contained approx. 0.5 g soluble dietary fibre (enzymicgravimetric methodology), 62% of which were polysaccharides. The remainder was composed of Maillard reaction products and other nonidentified substances. Galactomannans and type II arabinogalactans were present in almost equal proportions. Coffee dietary fibre was readily fermented by human faecal slurries, resulting in the production of short-chain fatty acids (SCFA). After 24 h of fermentation, 85% of total carbohydrates were degraded. In general, arabinosyl units from the polysaccharide fraction were degraded at a slower rate than mannosyl and galactosyl units. In the process of depolymerisation arabinogalactans were debranched and the ratio of (1<right arrow>3)-linked to (1<right arrow>6)-linked galactosyl residues decreased. Structural units composed of (1<right arrow>5)-linked arabinosyl residues were least degradable, whereas terminally linked arabinosyl residues were easily utilized. The impact of coffee fibre on numerically dominant population groups of the intestinal microbiota was investigated by fluorescence in situ hybridization combined with flow cytometry (FISH-FC). After 24 h of fermentation, an increase of approx. 60% of species belonging to the Bacteroides-Prevotella group was observed. The growth of bifidobacteria and lactobacilli was not stimulated.
Camassola, M.; Dillon, A. J.
In this work, the effect of supplementing liquid cellulase production media (CPM) with methylxanthines (aminophylline, caffeine and theophylline), with and without the addition of glucose, on the secretion of cellulases by Penicillium echinulatum strain 2HH (wild-type) and the derived mutant strain 9A02S1 was studied. METHODS AND RESULTS: When compared with unsupplemented CPM, both strains produced higher beta-glucosidase and filter paper activities (FPAs) in CPM supplemented with 1 micromol l(-1) of caffeine but lower activities with 5 micromol l(-1) of caffeine. With theophylline only, strain 9A02S1 produced higher beta-glucosidase and FPAs, while aminophylline produced no effect on the cellulase activity of either strain. Supplementation of CPM with 0.5% (w/v) of glucose plus caffeine resulted in higher beta-glucosidase and FPAs being produced by strain 2HH, but not strain 9A02S1, than
in CPM supplemented with 0.5% (w/v) of glucose only. CONCLUSIONS: These results indicate that different concentrations of caffeine and theophylline can increase the beta-glucosidase and FPAs produced by P. echinulatum strains 2HH and 9A02S1. SIGNIFICANCE AND IMPACT OF THE STUDY: The results suggest that some methylxanthines, in adequate concentration, can be used as media components to increase cellulase production.
Kouadio, A. I.; Lebrihi, A.; Agbo, G. N.; Mathieu, F.; Pfohl-Leszkowiz, A.; Dosso, M. B.
: In the present study, the effect of temp. and aw on fungal growth and ochratoxin production on coffee-based medium was assessed. Optimal growth of 3 Aspergillus strains was observed in the same ecological conditions, namely 30°C and 0.99 aw. Max. daily growth was 11.2, 6.92 and 7.22 mm/day for A. niger, A. carbonarius and A. ochraceus, respectively. However, ecological conditions for optimal ochratoxin production varied according to the toxinogenic strain, with aw as a limiting factor. Ochratoxin A production was inhibited at 42°C and 0.75 aw. Correspondence between laboratory tested aw and that measured on a sun-dried ripe cherry batch showed that the first 5 days of drying were critical for fungal growth and ochratoxin A production. It is concluded that artificial drying of cherries at temp. > 42°C will impede not only fungal growth but also contamination with ochratoxin A.
Patui, S.; Peresson, C.; Braidot, E.; Tubaro, F.; Colussi, A.; Bonnlander, B.; Macri, F.; Vianello, A.
In this paper lipoxygenase (LOX) presence was investigated in coffee berries to determine its involvement in lipid degradative metabolism of plants grown in organic and conventional cultivations. An immunochemical analysis has evidenced a ca. 80 kDa protein, cross-reacting with an anti-LOX antibody, only in the pulp fraction of berries obtained from plants of both cultivations. LOX activity in this fraction could be monitored either as conjugated diene formation or reaction products (determined by HPLC) and was mainly associated with a heavy membrane fraction (HMF, enriched in tonoplast, endoplasmic reticulum, plasma membrane, and mitochondria) and a light membrane fraction (LMF, enriched in plasma membrane and endoplasmic reticulum, with low levels of tonoplast and mitochondria). The LOX activity of LMF from berries of both cultivations showed an optimum at pH 8.0. The HMF exhibited a different activity peak in samples from conventional (pH 8.0) and organic (pH 5.5) cultures, suggesting the presence of different isoenzymes. These findings were also confirmed by variation of the ratio of 9- and 13-hydroperoxides in organic (1:1) and conventional cultivations (1:10), indicating that the organic one was subjected to an oxidative stress in the coffee pulp fraction leading to the expression of an acidic LOX. Such de novo synthesized LOX activity could be responsible for the production of secondary metabolites, which may interfere with the organoleptic profile of coffee.
McCarthy, A. A.; McCarthy, J. G.
Caffeine (1,3,7-trimethylxanthine) is a secondary metabolite produced by certain plant species and an important component of coffee (Coffea arabica and Coffea canephora) and tea (Camellia sinensis). Here we describe the structures of two S-adenosyl-l-methionine-dependent N-methyltransferases that mediate caffeine biosynthesis in C. canephora \'robusta\', xanthosine (XR) methyltransferase (XMT), and 1,7-dimethylxanthine methyltransferase (DXMT). Both were cocrystallized with the demethylated cofactor, Sadenosyl-L-cysteine, and substrate, either xanthosine or theobromine. Our structures reveal several elements that appear critical for substrate selectivity. Serine-316 in XMT appears central to the recognition of XR. Likewise, a change from glutamine-161 in XMT to histidine-160 in DXMT is likely to have catalytic consequences. A phenylalanine-266 to isoleucine-266 change in DXMT is also likely to be crucial for the discrimination between mono and dimethyl transferases in coffee. These key residues are probably functionally important and will guide future studies with implications for the biosynthesis of caffeine and its derivatives in plants.
Herrera, J. C.; D\'Hont, A.; Lashermes, P.
Fluorescence in situ hybridization (FISH) was used to study the presence of alien chromatin in interspecific hybrids and one introgressed line (S.288) derived from crosses between the cultivated species Coffea arabica and the diploid relatives C. canephora and C. liberica. In situ hybridization using genomic DNA from C. canephora and C. arabica as probes showed elevated cross hybridization along the hybrid genome, confirming the weak differentiation between parental genomes. According to our genomic in situ hybridization (GISH) data, the observed genomic resemblance between the modern C. canephora genome (C) and the C. canephora-derived subgenome of C. arabica (Ca) appears rather considerable. Poor discrimination between C and Ca chromosomes supports the idea of low structural modifications of both genomes since the C. arabica speciation, at least in the frequency and distribution of repetitive sequences. GISH was also used to identify alien chromatin segments on chromosome spreads of a C. liberica-introgressed line of C. arabica. Further, use of GISH together with BAC-FISH analysis gave us additional valuable information about the physical localization of the C. liberica fragments carrying the SH3 factor involved in resistance to the coffee leaf rust. Overall, our results illustrate that FISH analysis is a complementary tool for molecular cytogenetic studies in coffee, providing rapid localization of either specific chromosomes or alien chromatin in introgressed genotypes derived from diploid species displaying substantial genomic differentiation from C. arabica.
Source : Genome 2007 vol.50 (7), pp 619 - 626