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At least 19 recordsLinked to original sources
PubMed2005

Polyphenoloxidase activity in coffee leaves and its role in resistance against the coffee leaf miner and coffee leaf rust.

In plants, PPO has been related to defense mechanism against pathogens and insects and this role was investigated in coffee trees regarding resistance against a leaf miner and coffee leaf rust disease. PPO activity was evaluated in different genotypes and in relation to methyl-jasmonate (Meja) treatment and mechanical damage. Evaluations were also performed using compatible and incompatible interactions of coffee with the fungus Hemileia vastatrix (causal agent of the leaf orange rust disease) and the insect Leucoptera coffeella (coffee leaf miner). The constitutive level of PPO activity observed for the 15 genotypes ranged from 3.8 to 88 units of activity/mg protein. However, no direct relationship was found with resistance of coffee to the fungus or insect. Chlorogenic acid (5-caffeoylquinic acid), the best substrate for coffee leaf PPO, was not related to resistance, suggesting that oxidation of other phenolics by PPO might play a role, as indicated by HPLC profiles. Mechanical damage, Meja treatment, H. vastatrix fungus inoculation and L. coffeella infestation caused different responses in PPO activity. These results suggest that coffee resistance may be related to the oxidative potential of the tissue regarding the phenolic composition rather than simply to a higher PPO activity.

Acetates↗
PubMed1977

[Studies on coffee and coffee substitutes. XIX. Dependence of the quantity of a highly polymeric galactomannan on the degree of extraction coffee-extracts (author's transl)].

In extracts of Columbia Arabica Coffee the content of galactomannan precipitable with alcaline copper solution decreases slowly up to an extraction yield of 43.6%; it decreases somewhat more rapidly with higher extraction yields. An extract of Angola Robusta Coffee showed opposite behaviour. In this case the content of galactomannan increased with the extraction yield, although not evenly. Calculated on the basis of roasted coffee solids the extract of the Arabica coffee had a rather limited range precipitable polysaccharide, the Robusta coffee in contrast with rated increased amounts of galactomannan. The different behaviour of the two coffee varieties may be due to mote or less strong binding of this high-polymer carbohydrate to the cell wall.

Cell Wall↗
PubMed1976

[Studies of coffee and coffee-substitute. XVIII. Dependence of the quantity and composition of a high polymer galactomannan on the coffee species and degree of roasting (authors transl)].

It is possible to determine quantitatively with satisfactory accuracy the galactomannan which is precipitated in coffee brew after addition of Fehling solution. The content of polysaccharides in the extracts increases with the degree of roasting. Galactomannan makes up 6.6 to 12.7% of the dry matter of the extracts and 1.8 to 4.4% of that of roast coffee. It consists mainly of mannan, to a much smaller degree of galactan. Often there are traces of glucan. The content of mannan increases with the degree of roasting while that of galactan decreases very rapidly.

Coffee↗
PubMed1995

Effect of different coffees on esophageal acid contact time and symptoms in coffee-sensitive subjects.

The purpose of this study was to correlate the effects of different coffees on esophageal acid contact, heartburn, and regurgitation in patients with coffee-sensitivity. Twenty volunteers with coffee-sensitivity were studied in a double-blind, 3 period, crossover study examining the effect of three regular (caffeinated) coffees (a coffee from the USA--"A"; a "treated" coffee from Europe--"B"; and an "untreated" coffee from Europe--"C") before and after a high-fat test meal. The median acid contact times for coffees A, B, and C were 6.5%, 9%, and 10.5%, respectively (A vs. C, p = 0.005). Significantly fewer patients reported any symptoms with coffee A compared with coffee C (p < 0.05). Symptoms were usually more frequent and severe after the test meal. There was a trend toward fewer and less severe symptoms with the treated coffee (B) compared with its untreated counterpart (C). Our conclusions are as follows: (a) Different coffees induce variations in gastroesophageal reflux in coffee-sensitive individuals. (b) Coffee can be treated in a manner which decreases heartburn symptoms by 75% while decreasing acid contact by only 14%. (c) Gastroesophageal reflux and symptoms of coffee sensitivity increase with the concomitant ingestion of food. (d) Symptoms of dyspepsia appear to be influenced by variations in both the coffee itself and characteristics of susceptible individuals. (e) Although gastroesophageal reflux is important in the genesis of coffee-sensitivity, there must be other factors which act in concert with reflux to produce symptoms of coffee-sensitivity.

Adult↗
PubMed1990

Comparison of coffee intake and coffee-induced symptoms in patients with duodenal ulcer, nonulcer dyspepsia, and normal controls.

Coffee and decaffeinated coffee stimulate acid secretion. In addition, many patients experience dyspepsia after coffee ingestion. Therefore, coffee is often prohibited by physicians in patients with peptic diseases. However, the association between peptic disease and symptoms remains unclear. This study compares coffee intake and the induction of symptoms by coffee in patients with duodenal ulcer disease, nonulcer dyspepsia, and normal controls. We have studied the coffee drinking habits of 58 duodenal ulcer patients, 55 nonulcer dyspepsia patients, and 55 normal controls. The use of coffee on a daily basis was not significantly different between duodenal ulcer patients (64%) and controls (56%), or between nonulcer dyspepsia patients (55%) and controls. There was also no difference between the three groups in the use of decaffeinated coffee, the number of cups per day, the method of preparation, the length of time of coffee use, or any change in coffee intake in the previous year. The intake of tea, caffeinated carbonated beverages, and aspirin or nonsteroidal anti-inflammatory drugs was also similar in the three groups. The duodenal ulcer patients were more likely to be cigarette smokers (45%) than either the controls (16%) or the nonulcer dyspepsia patients (24%). Daily alcohol intake was not significantly different in the three groups. The prevalence of coffee induction of dyspeptic symptoms was similar in duodenal ulcer patients (29%) and controls (22%), but was much more common in nonulcer dyspepsia patients (53%) than in controls (22%), p = 0.0036. In conclusion, there was no difference in coffee intake between patients with duodenal ulcer, nonulcer dyspepsia, or normal controls. However, patients with nonulcer dyspepsia, but not duodenal ulcer, were more likely to experience dyspeptic symptoms after coffee ingestion.

Caffeine↗
PubMed2003

A randomized, double-blind comparison of two different coffee-roasting processes on development of heartburn and dyspepsia in coffee-sensitive individuals.

The mechanism underlying coffee-induced heartburn and dyspepsia remains poorly understood. This has led to speculation that variations in coffee processing may be important. The primary objective of this study was to determine whether a coffee brewed with coffee beans processed using conduction roasting will result in fewer symptoms of gastroesophageal reflux and dyspepsia in coffee-sensitive individuals compared to a differently processed yet otherwise similar coffee. Thirty coffee-sensitive individuals completed this single-center, randomized, double-blind, crossover study in which the symptoms of heartburn, regurgitation and dyspepsia were assessed following coffee consumption both in the fasting state and after ingestion of a standard test meal. Consumption of both coffees resulted in heartburn, regurgitation, and dyspepsia in most individuals. No significant differences in the frequency or severity of heartburn, regurgitation, or dyspepsia were demonstrated between the two coffees either in the fasting state or after the test meal. We conclude that differences in the coffee bean roasting process do not result in marked differences in coffee-induced upper gastrointestinal symptoms.

Adult↗
PubMed2005

Coffee blunts mental stress-induced blood pressure increase in habitual but not in nonhabitual coffee drinkers.

Coffee is widely consumed, especially during mental stress conditions. Cardiovascular impact of coffee remains debated because the underlying mechanisms of action are complex. We reported previously differential cardiovascular stimulation of coffee at rest depending on habitual consumption. The present study was designed to evaluate the effects of coffee on cardiovascular response to mental stress. In 15 healthy volunteers (6 habitual, 9 nonhabitual coffee drinkers), we assessed the effect of mental stress on blood pressure (BP), heart rate (HR), and muscle sympathetic activity (MSA) before and after a triple espresso, intravenous caffeine, and placebo in the same subjects. Under baseline conditions, mental stress significantly increases MSA (+2.5+/-0.7 volts per minute; +14.1+/-10.3%), systolic (+11.6+/-4.1 mm Hg) and diastolic BP (+6.4+/-2.0 mm Hg), and HR (+9.6+/-1.8 minutes(-1)). In nonhabitual coffee drinkers, a triple espresso but not caffeine induced an additional increase in systolic BP (+9+/-6.3 mm Hg; P=0.003) during mental stress, whereas in habitual drinkers, the stress-induced BP increase was blunted (+4+/-3.9 mm Hg; P=NS). As a result, nonhabitual coffee drinkers experienced significantly higher BP during mental stress than habitual drinkers (151+/-17.9/83+/-5.6 mm Hg versus 130+/-7.8/74+/-6.7 mm Hg; P<0.05). Caffeine induced similar effects in habitual and nonhabitual coffee drinkers at rest and during mental stress. The response to the cold pressor test was not influenced by coffee drinking in both groups. In conclusion, in nonhabitual coffee drinkers, coffee enhances the cardiovascular response to mental stress with an additional increase in systolic BP, whereas in habitual drinkers, the response is blunted. Caffeine alone does not exert any potentiating effect, confirming that ingredients other than caffeine are partially responsible for the stimulating effect of coffee on the cardiovascular system.

Adult↗
PubMed2000

Coffee and fitness-coffee suppresses lipopolysaccharide-induced liver injury in rats.

To clarify the relationship between coffee and fitness, we investigated the effect of coffee on weight gain and total cholesterol as well as production of cytokines and activities of GOT (aspartate aminotransferase; EC 2.6.1.1.) and GPT (alanine aminotransferase; EC 2.6.1.2.) as injected lipopolysaccharides. Forty-eight male Wistar rats were divided into three dietary groups (n=16), which were fed a stock diet (control group), the diet supplemented with freeze-dried coffee of 6.2 g/kg (0.62% coffee group), and the diet supplemented with freeze-dried coffee of 13.6 g/kg (1.36% coffee group). It was confirmed by HPLC analysis that the serum caffeine concentrations in both coffee groups became significantly higher in 140 days after the start of feeding. No significant differences in body weight and serum cholesterol were found between the coffee groups and control group, though the coffee groups tended to be somewhat high at cholesterol level. Activities of serum GOT and GPT increased at 2 h after LPS injection, but in the coffee groups were significantly suppressed (p<0.05). However, the coffee feeding could not suppress the increases of serum cytokine (TNF-alpha and IL-6) levels. These results suggest that coffee may serve as a preventive against liver injury.

Alanine Transaminase↗
PubMed1992

Wake up and smell the coffee. Caffeine, coffee, and the medical consequences.

Caffeine is a methylxanthine whose primary biologic effect is antagonism of the adenosine receptor. Its presence in coffee, tea, soda beverages, chocolate, and many prescription and over-the-counter drugs makes it the most commonly consumed stimulant drug. Initially caffeine increases blood pressure, plasma catecholamine levels, plasma renin activity, serum free fatty acid levels, urine production, and gastric acid secretion. Its long-term effects have been more difficult to substantiate. Most of the caffeine consumed in the United States is in coffee, which contains many other chemicals that may have other biologic actions. The consumption of coffee is a self-reinforcing behavior, and caffeine dependence and addiction are common. Coffee and caffeine intake have been linked to many illnesses, but definitive correlations have been difficult to substantiate. Initial trials showing coffee's association with coronary disease and myocardial infarction have been difficult to reproduce and have many confounding variables. Recent studies showing a larger effect over long follow-up periods and with heavy coffee consumption have again brought the question of the role of coffee in disease states to the fore. Caffeine in average dosages does not seem to increase the risk of arrhythmia. At present there is no convincing evidence that caffeine or coffee consumption increases the risk for any solid tumor. The intake of coffee and caffeine has clearly been decreasing in this country over the past two decades, largely brought about by the increasing health consciousness of Americans. Although there have been many studies that hint that the fears of increased disease with coffee drinking may be warranted, many questions have yet to be answered about the health effects of coffee and caffeine use.

Arrhythmias, Cardiac↗
PubMed2003

Evolution of green coffee protein profiles with maturation and relationship to coffee cup quality.

Coffee flavor is the product of a complex chain of chemical transformations. The green bean has only a faint odor that is not at all reminiscent of coffee aroma. It contains, however, all of the necessary precursors to generate the unmistakable coffee flavor during roasting. The levels and biochemical status of these precursors may vary in relation to genetic traits, environmental factors, maturation level, postharvest treatment, and storage. To improve our understanding of coffee flavor generation, the sensory and biochemical impact of maturation was assessed. Maturation clearly favored the development of high-quality flavor in the coffee brew. A specific subclass of green coffee beans, however, generated high-quality coffee flavor irrespective of maturation. Biochemical aspects were examined using a dynamic system: immature and mature green coffee suspensions were incubated under air or argon. On the analytical side, a specific pool of flavor precursors was monitored: chlorogenic acids, green coffee proteins, and free amino acids. A link between maturation, the redox behavior of green coffee suspensions, and their sensory scores was identified. Compared to ripe beans, unripe beans were found to be more sensitive to oxidation of chlorogenic acids. Aerobic incubation also triggered the fragmentation or digestion of the 11S seed storage protein and the release of free amino acids.

Amino Acids↗
PubMed1995

Factors related to the development of sensitization to green coffee and castor bean allergens among coffee workers.

BACKGROUND: Occupational allergic respiratory symptoms in coffee workers have been frequently reported, but the ultimate cause of sensitization is still debated, castor bean being considered besides green coffee beans. Atopy and cigarette smoking have been suggested as promoting factors of sensitization for several occupational allergens. OBJECTIVE: This study was carried out to assess the prevalence of allergic respiratory symptoms and of sensitization to both green coffee beans and castor bean in the whole workforce of a coffee manufacturing plant. Furthermore we wanted to ascertain both the presence of castor bean antigens in the settled dust of the green coffee beans warehouse and the possible crossreactivity between the two beans. Meanwhile, the effect of smoking and atopy was considered. METHOD: Two-hundred and eleven workers were examined. A questionnaire on oculorhinitis and asthma was administered and skin-prick tests for green coffee beans, castor bean and 15 common inhalant allergens were carried out. Isoelectric focusing, isoelectric focusing immunoblot and radioallergosorbent assay (RAST) inhibition were performed on samples of settled environmental dust from the green coffee area, as well as on castor bean and green coffee beans. RESULTS: Ten per cent of the workers complained of oculorhinitis alone and 16% of asthma (nearly always associated with oculorhinitis). The overall prevalence of skin-sensitization was: 15% for green coffee beans, 22% for castor bean, 22% for common allergens. Evidence of sensitization to occupational allergens was more common in smokers, with a more than twofold increase in relative risk. The strong association between skin positivity to common and occupational allergens suggests that atopy acts as an enhancing host factor towards occupational sensitization. The analysis of the dust confirmed the presence of castor bean antigens. CONCLUSION: Our findings indicate that castor bean is the major cause of occupational sensitization among coffee workers, whereas smoking and atopy act as enhancing factors.

Adult↗
PubMed1976

Coffee grounds. I. Effects of coffee grounds on ration digestibility and diuresis in cattle, on in vitro rumen fermentation, and on rat growth.

Holstein steers were used to compare rations in which coffee grounds replaced grain at rates of 0, 5, 10, or 20%. The coffee grounds analyzed (%) dry matter 91.1, protein 11.8, fat 23.1, fiber 42.5, ash .7, and caffeine .13. Digestibility coefficients for dry matter, crude protein, and energy decreased, and ether extract increased progressively as concentrations of coffee grounds in the ration were increased. There was a significant decrease in nitrogen retention and utilization when the rations contained 10 or 20% coffee grounds. Coffee grounds depressed feed intake, increased urinary output, and increased water intake (based on dry matter intake). Coffee grounds caused diuresis and renal, urethral, and bladder irritation. Adding coffee grounds up to 35% of the substrate did not depress rumen microbial fermentation, as measured by in vitro gas production. Weight gain of rats fed rations containing 22.5% untreated coffee grounds was reduced significantly. Water extraction removed some undersirable factors in coffee grounds for rats, and ether extraction removed most of them. Incremental additions of coffee oil (1, 3, or 5%) to the basal diet resulted in incremental decreases in rat weight gain.

Animal Feed↗
PubMed1976

[Coffee hulls and pulp. XII. Effect of storage of coffee pulp on its nutritive value for calves].

Coffee pulp, dehydrated and stored for 7, 13 and 17 months or ensiled for 4, 10 and 14 months, was studied in calves with a rapid growing rate. Storage of dehydrated coffee pulp did not affect its chemical composition, but ensiling reduced crude fiber and increased its nitrogen free extract content after 10 and 14 months. Three growth trials were carried out with Holstein calves averaging 95 kg in the first and second trials, and 130 kg in the third. Eighteen calves were used in the first trial and 24 in each of the other two. In each trial the animals were divided into three equal groups and randomly assigned to one of the following treatments: control, which contained 48% cottonseed hulls, and the other two, with 30% dehydrated coffee pulp or 30% ensiled coffee pulp. Basically, the difference between trials consisted in the time of storage or ensiling of coffee pulp. In all trials, weight gains of calves fed coffee pulp (1.00, 0.90 and 0.98 kg/day, and 1.06, 0.94 and 1.08 kg/day, respectively) were significantly lower (P less than 0.05) than the weight gains induced by the control ration (1.21, 1.08 and 1.19 kg/day). Feed intake was also lower, but feed conversion ratio was higher for those rations containing coffee pulp. Calf performance was better with ensiled than with deydrated coffee pulp, particularly in the third trial, where the differences in weight gains were significantly higher (P less than 0.05). It is concluded that storage time does not change nutritive value of coffee pulp; and the ensiling is an adequate process for storing pulp during coffee harvesting, and, possibly also, for improving its nutritive value.

Animal Feed↗
PubMed2005

Coffee consumption and human health--beneficial or detrimental?--Mechanisms for effects of coffee consumption on different risk factors for cardiovascular disease and type 2 diabetes mellitus.

Coffee is probably the most frequently ingested beverage worldwide. Especially Scandinavia has a high prevalence of coffee-drinkers, and they traditionally make their coffee by boiling ground coffee beans and water. Because of its consumption in most countries in the world, it is interesting, from both a public and a scientific perspective, to discuss its potential benefits or adverse aspects in relation to especially two main health problems, namely cardiovascular disease and type 2 diabetes mellitus. Epidemiological studies suggest that consumption of boiled coffee is associated with elevated risk for cardiovascular disease. This is mainly due to the two diterpenes identified in the lipid fraction of coffee grounds, cafestol and kahweol. These compounds promote increased plasma concentration of cholesterol in humans. Coffee is also a rich source of many other ingredients that may contribute to its biological activity, like heterocyclic compounds that exhibit strong antioxidant activity. Based on the literature reviewed, it is apparent that moderate daily filtered, coffee intake is not associated with any adverse effects on cardiovascular outcome. On the contrary, the data shows that coffee has a significant antioxidant activity, and may have an inverse association with the risk of type 2 diabetes mellitus.

Animals↗
PubMed2005

Human monoamine oxidase enzyme inhibition by coffee and beta-carbolines norharman and harman isolated from coffee.

Monoamine oxidase (MAO) is a mitochondrial outer-membrane flavoenzyme involved in brain and peripheral oxidative catabolism of neurotransmitters and xenobiotic amines, including neurotoxic amines, and a well-known target for antidepressant and neuroprotective drugs. Recent epidemiological studies have consistently shown that coffee drinkers have an apparently lower incidence of Parkinson's disease (PD), suggesting that coffee might somehow act as a purported neuroprotectant. In this paper, "ready to drink" coffee brews exhibited inhibitory properties on recombinant human MAO A and B isozymes catalyzing the oxidative deamination of kynuramine, suggesting that coffee contains compounds acting as MAO inhibitors. MAO inhibition was reversible and competitive for MAO A and MAO B. Subsequently, the pyrido-indole (beta-carboline) alkaloids, norharman and harman, were identified and isolated from MAO-inhibiting coffee, and were good inhibitors on MAO A (harman and norharman) and MAO B (norharman) isozymes. beta-carbolines isolated from ready-to-drink coffee were competitive and reversible inhibitors and appeared up to 210 microg/L, confirming that coffee is the most important exogenous source of these alkaloids in addition to cigarette smoking. Inhibition of MAO enzymes by coffee and the presence of MAO inhibitors that are also neuroactive, such as beta-carbolines and eventually others, might play a role in the neuroactive actions including a purported neuroprotection associated with coffee consumption.

Carbolines↗
PubMed2006

Germination of coffee seeds and its significance for coffee quality.

Besides genotypic characteristics, the crucial factor that determines coffee quality is the mode of post-harvest treatment, i.e., the wet and dry processing. Up to now, the resulting characteristic flavour differences between these differentially processed coffees were attributed exclusively to differences in starting material. However, as these quality differences are still evident, even when identical coffee samples were processed by the two methods in parallel, the differences must be created by metabolic processes in the coffee beans themselves. Based on expression studies of the germination-specific isocitrate lyase and the resumption of cell cycle activity, monitored by the abundance of beta-tubulin, we evidence that germination is initiated in coffee seeds during the course of standard coffee post-harvest treatments. The extent and nature of the germination processes depend on the processing method. The coherence of metabolic events, substantial differences in the chemical composition of the coffee beans, and the generation of specific coffee qualities establishes the basis for a quite novel approach in coffee research.

Coffea↗