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PubMed2001

Molecular and biochemical characterization of endo-beta-mannanases from germinating coffee (Coffea arabica) grains.

The activity of endo-beta-mannanase ([1-->4]-beta-mannan endohydrolase EC 3.2.1.78) is likely to be central to the metabolism of cell wall mannans during the germination of grains of coffee (Coffea spp.). In the present paper, we report the cloning and sequencing of two endo-beta-mannanase cDNAs (manA and manB) by different strategies from Coffea arabica L.. The manA cDNA was obtained by the use of oligonucleotides homologous to published sequences of other endo-beta-mannanases and manB by the use of oligonucleotides deduced from a purified enzyme from coffee. ManA and B proteins share about 56% sequence homology and include highly conserved regions found in other mannan endohydrolases. Purification of the activity by chromatography followed by separation by two-dimensional electrophoresis and amino acid sequencing demonstrated the existence of at least seven isomers of the ManB form. The existence of multiple manB genes was also indicated by Southern analysis, whereas only one or two gene copies were detected for manA. Northern hybridizations with manA- and manB-specific probes showed that mRNA transcripts for both cDNAs were present at the same periods of bean germination with transcript peaks at 20 days after imbibition of water (DAI). Transcripts were not detected during grain maturation or in the other tissues such as roots, stems, flowers and leaves. The peak endo-beta-mannanase activity occurred at approximately 28 DAI and was not detected in grains prior to imbibition. Activity and mRNA levels appeared to be tightly co-ordinated. Tests of substrate specificity with the purified ManB enzyme showed that activity required a minimum of five mannose units to function efficiently.

Amino Acid Sequence↗

PubMed2006

Phenol contents, oxidase activities, and the resistance of coffee to the leaf miner Leucoptera coffeella.

We examined the role of phenolic compounds, and the enzymes peroxidase and polyphenol oxidase, in the expression of resistance of coffee plants to Leucoptera coffeella (Lepidoptera: Lyonetiidae). The concentrations of total soluble phenols and chlorogenic acid (5-caffeoylquinic acid), and the activities of the oxidative enzymes peroxidase (POD) and polyphenol oxidase (PPO), were estimated in leaves of Coffea arabica, C. racemosa, and progenies of crosses between these species, which have different levels of resistance, before and after attack by this insect. The results indicate that phenols do not play a central role in resistance to the coffee leaf miner. Differences were detected between the parental species in terms of total soluble phenol concentrations and activities of the oxidative enzymes. However, resistant and susceptible hybrid plants did not differ in any of these characteristics. Significant induction of chlorogenic acid and PPO was only found in C. racemosa, the parental donator of the resistance genes against L. coffeella. High-performance liquid chromatography (HPLC) analysis also showed qualitative similarity between hybrids and the susceptible C. arabica. These results suggest that the phenolic content and activities of POD and PPO in response to the attack by the leaf miner may not be a strong evidence of their participation in direct defensive mechanisms.

Animals↗

PubMed1992

Stereochemistry of D-galactal and D-galacto-octenitol hydration by coffee bean alpha-galactosidase: insight into catalytic functioning of the enzyme.

Green coffee bean alpha-galactosidase was found to catalyze the hydration of D-galactal and (Z)-3,7-anhydro-1,2-dideoxy-D-galacto-oct-2-enitol (D-galacto-octenitol), each a known substrate for beta-galactosidase. The hydration of D-galactal by the alpha-galactosidase in D2O yielded 2-deoxy-2(S)-D-[2-2H]galactose; the hydration of D-[2-2H]galacto-octenitol in H2O yielded 1,2-dideoxy-2(R)-D-[2-2H]galactooct-3-ulose. Thus, the enzyme protonated each substrate from beneath the plane of the ring, as assumed for alpha-D-galactosides. These results provide an unequivocal assignment of the orientation of an acidic catalytic group to the alpha-galactosidase reaction center. In addition, they reveal a pattern of glycal/exocyclic enitol/glycoside protonation by the enzyme that differs from the pattern reported for beta-galactosidase and from that reported for alpha-glucosidases. Further findings show that D-galacto-octenitol is hydrated by the coffee bean alpha-galactosidase to form the alpha-anomer of 1,2-dideoxy-D-galactooctulose and by Escherichia coli beta-galactosidase to form the beta-anomer. That each enzyme converts this enolic substrate to a product whose de novo anomeric configuration matches that formed from its D-galactosidic substrates provides new evidence for the role of protein structure in controlling the steric outcome of reactions catalyzed by these and other glycosylases. The findings are discussed in light of the concept that catalysis by glycosidases involves a "plastic" protonation phase and a "conserved" product configuration phase.

Carbohydrate Conformation↗

PubMed1996

Determination of serotonin released from coffee wax by liquid chromatography.

A simple hydrolysis and extraction method was developed for the release of serotonin (5-hydroxytryptamine) from a coffee wax sample obtained from decaffeination of coffee beans. The recoverable amount of serotonin was determined by reversed-phase high-performance liquid chromatography with gradient elution and UV detection, using the standard addition method. Different type of basic deactivated chromatographic columns were used for the separation.

Chromatography, High Pressure Liquid↗

PubMed1995

Change in alcohol, tobacco and coffee consumption in pregnant women: evolution between 1988 and 1992 in an area of high consumption.

OBJECTIVE: Analyse the evolution of alcohol, tobacco and coffee consumption during pregnancy in a population characterized by a high level of consumption and a low socioeconomic situation. STUDY DESIGN: Data were obtained from two studies done with the same protocol and questionnaire in the Roubaix Public Maternity Hospital in 1988 (176 women) and 1992 (235 women); the two periods were compared using univariate tests and multiple logistic regression to control for social factors. RESULTS: Between 1988 and 1992, there was a clear decrease in alcohol consumption, a slight decrease in coffee consumption and an increase in tobacco use. These changes affected usual consumption as well as consumption during pregnancy. The increase in tobacco use was no longer significant after controlling for social factors. However, the decrease in alcohol consumption affected all women regardless of sociodemographic characteristics, and remained significant after controlling for these characteristics. CONCLUSION: Several factors support the hypothesis that the decrease in the reported alcohol consumption is real, for consumptions in the low to moderate range. However, it is difficult to identify the role of the several factors involved in this evolution: behaviour of the general population, attitude among pregnant women, information and sensitization of prenatal care providers. Besides, one negative aspect needs to be considered: the stability of the incidence of fetal alcohol syndrome, probably reflecting the stability of the proportion of very heavy consumers.

Alcohol Drinking↗

PubMed1988

Inhibition of hamster buccal pouch carcinogenesis by green coffee beans.

Forty female Syrian Golden hamsters were divided into two equal groups and placed on one of two diets. The hamsters in Group I received a normal chow, and the animals in Group II were given the same chow supplemented with powdered green coffee beans (20%). After the hamsters adjusted to the diets, 16 animals from each group were selected. The right buccal pouch of each of these hamsters was painted three times weekly with a 0.5% solution of 7, 12-dimethylbenz(a)anthracene (DMBA) in heavy mineral oil. The eight remaining animals, four in each group, served as controls and were treated three times weekly with heavy mineral oil. After a total of 50 treatments (16 1/2 weeks), the hamsters were killed. The animals receiving green coffee beans exhibited a significant delay in the development of DMBA-induced carcinogenesis of the buccal pouch mucosa, as determined by both visual and histologic examination.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1991

Behavioral and biochemical consequences of perinatal exposure of mice to instant coffee: a correlative evaluation.

In the present study, the lasting effects of prepartum and perinatally consumed instant coffee by female mice on the behavior as well as on the level of activities of certain enzymes in the tissues of their male offspring have been investigated. The behavioral observations of nonsocial investigation, defense, displacement, latency to threat and naso-nasal contact has decreased significantly in offspring of treated mothers, while the threat, attack, latency to threat and attack and number of fights have increased significantly. Hence, coffee has proven to be an inducer of hyperactive behavior in these offspring. Such effects are both dose dependent and duration-of-treatment dependent. Moreover, variations were detected in the level of AChE activity in the brain tissues of these offspring together with variations in the levels of AcPase and AlPase activities in their liver, kidneys and testes. Such variations in these organs have developed in utero, making these enzymes convenient markers in teratological studies.

Acetylcholinesterase↗

PubMed1981

Non-mutagenicity of urine from coffee drinkers compared with that from cigarette smokers.

The urine of human coffee drinkers who ingested 12 g of instant coffee per day, during 4 days in a first experiment or 12 g within 2 h in a second experiment, was fractionated by XAD-2 column chromatography. The non-polar urine fractions so obtained were not mutagenic in the Ames Salmonella tester strains TA98 or TA100 in either experiment, either with or without beta-glucuronidase treatment of the urine. The non-polar urine fraction of smokers, who smoked 20--30 cigarettes per day during 4 days in the first experiment or 7--18 cigarettes during 7 h in the second experiment, was mutagenic when metabolically activated.

Adult↗

PubMed1984

Mutagenicity of instant coffee on cultured Chinese hamster lung cells.

Coffee showed mutagenic activity in cultured Chinese hamster lung (CHL) cells as assessed by using diphtheria toxin resistance as a selective marker. Most of the mutagenicity was suppressed in the presence of sodium bisulfite. The contribution of methylglyoxal to the total mutagenicity of coffee was less than 3%.

Aldehydes↗

PubMed1990

N-2 acetylation of 2'-deoxyguanosine by coffee mutagens, methylglyoxal and hydrogen peroxide.

Coffee shows direct-acting mutagenicity in Salmonella typhimurium TA100 and most of this mutagenicity is due to the synergistic effects of methylglyoxal and hydrogen peroxide. The modifications of deoxyribonucleosides by methylglyoxal plus hydrogen peroxide were studied in vitro. When 2'-deoxyguanosine (6.25 mumole) was treated with methylglyoxal (125 mumole) and hydrogen peroxide (125 mumole) in 5 ml of 0.1 M phosphate buffer (pH 7.4) at 37 degrees C for 3 h, N2-acetyl-2'-deoxyguanosine was formed with a yield of 1.1%. Its formation increased time-dependently. By contrast, no appreciable modification of other deoxynucleosides was detected after their incubation with methylglyoxal and hydrogen peroxide under similar conditions. N2-Acetyl-2'-deoxyguanosine was also formed during incubation of 2'-deoxyguanosine with instant coffee.

Acetylation↗

PubMed1983

Reinforcements from the first drug experience can predict later drug habits and/or addiction: results with coffee, cigarettes, alcohol, barbiturates, minor and major tranquilizers, stimulants, marijuana, hallucinogens, heroin, opiates and cocaine.

The relationship between the reinforcing quality of the first drug experiences and eventual habits for a variety of drugs was studied in 42 male drug abusers who were predominantly opiate addicts. These subjects volunteered for drug studies carried out by the Addiction Research Center. The degree of reinforcement they derived from their first drug experience was related to their subsequent habit. This was true for alcohol, barbiturates, minor tranquilizers, cocaine, stimulants, marijuana, glue or solvents, hallucinogens, opiates other than heroin and heroin. Positive but non-significant correlations were found for coffee and major tranquilizers. The correlation for cigarettes was contrary to expectations. Of the components to the index of reinforcement, degree of liking of a drug on the first occasion was most related to the subsequent habit. The greatest initial reinforcement scores were found for heroin, cocaine and opiates other than heroin. drugs which were not well liked on the first occasion included major tranquilizers, cigarettes, coffee, and glue.

Adult↗

PubMed1989

Quality assessment of coffee beans with ESR and gamma-ray irradiation.

Peroxy radical formation in raw coffee beans of different qualities and origins from all over the world has been studied with electron spin resonance (ESR) analysis. The gamma-ray equivalent absorbed dose (ED) which creates the same concentration of radicals is obtained by the additive gamma-ray irradiation of the coffee beans. The ED and the cup quality is somewhat inversely related suggesting that the peroxidation of the unsaturated fatty acid is somewhat indicative of the degree of the aromatic decomposition and rancidity.

Coffee↗

PubMed1993

Coffee and alcohol intake as predictors of smoking cessation and tobacco withdrawal.

In one study of 105 smokers who received physician advice plus placebo gum and in another study of 630 self-quitters, neither the presence or absence, nor amount of precessation alcohol, nor coffee intake, nor changes in alcohol or coffee intake postcessation, predicted relapse or most withdrawal symptoms. The one possible exception was that heavy caffeine and alcohol users reported a greater increase in hunger and craving postcessation; however, these effects were not consistent across measures, follow-ups, and studies. Our results are inconsistent with theories that caffeine intoxication from increased caffeine blood levels postsmoking cessation worsen tobacco withdrawal or that alcohol or caffeine use during initial abstinence from smoking increases relapse to smoking.

Adult↗

PubMed2005

Comparative culturing of Pleurotus spp. on coffee pulp and wheat straw: biomass production and substrate biodegradation.

The results of the cultivation of six strains of Pleurotus (P. djamor (2), P. ostreatus (2) and P. pulmonarius (2)) on coffee pulp and wheat straw are presented. Metabolic activity associated with biomass of each strain was determined, as well as changes in lignin and polysaccharides (cellulose and hemicellulose), phenolic and caffeine contents in substrate samples colonized for a period of up to 36 days. Analysis were made of changes during the mycelium incubation period (16 days) and throughout different stages of fructification. Greater metabolic activity was observed in the wheat straw samples, with a significant increase between 4 and 12 days of incubation. The degradation of polysaccharide compounds was associated with the fruiting stage, while the reduction in phenolic contents was detected in both substrates samples during the first eight days of incubation. A decrease was observed in caffeine content of the coffee pulp samples during fruiting stage, which could mean that some caffeine accumulates in the fruiting bodies.

Biodegradation, Environmental↗

PubMed2006

The relationship between the consumption of meat, fat, and coffee and the risk of colon cancer: a prospective study in Japan.

The risk of the development of colon cancer in relation to a western diet was studied in a community-based cohort in Japan. From 1992 to 2000, 13,894 men and 16,327 women were followed. In men, high consumption of processed meat increased the risk in comparison with low consumption (adjusted RR=1.98, 95% CI: 1.24-3.16). In women, daily coffee drinkers had a reduced risk in comparison with individuals who never or rarely drank coffee (adjusted RR=0.43, 95% CI: 0.22-0.85). The findings suggest the possible linkage between a western diet and risk of colon cancer.

Adult↗

PubMed2004

Capillary electrophoresis for the analysis of short-chain organic acids in coffee.

A simple and rapid capillary electrophoresis method for low-molecular mass carboxylic acids measurement in coffee has been optimised and validated. Regarding separation conditions, phosphate concentration in the background electrolyte, surfactant type [cetyltrimethylammonium bromide (CTAB), tetradecyltri methylammonium bromide (TTAB) and hexadimethrine bromide (HDB)], percentages of organic modifier and pH were assayed. The best conditions were: 500 mM phosphate buffer at pH 6.25 with CTAB 0.5 mM. The separation was carried out with an uncoated fused-silica capillary (57 cm x 50 microm i.d.) which was operated at -10 kV potential. Detection was performed at 200 nm. In such conditions 17 short-chain organic acids: oxalic, formic, fumaric, mesaconic, succinic, maleic, malic, isocitric, citric, acetic, citraconic, glycolic, propionic, lactic, furanoic, pyroglutamic, quinic acids plus nitrate were separated, identified and measured. Validation parameters of the method allow us to consider it lineal, accurate and precise and, therefore, reliable for its employment in food composition studies or for quality control. Results in coffees with different industrial treatment allow the detection of important differences in the organic acid profile.

Acids↗

PubMed2004

Gourmet coffee beverage consumption among college women.

Gourmet coffee beverages (GCBs) are relatively new products in the foodservice industry that consist of high-energy coffee drinks. A descriptive study was conducted to evaluate the frequency of consumption of GCBs and their energy and fat contribution to overall dietary intake in college women using a beverage questionnaire and a 3-day food diary. A convenience sample of 165 undergraduate and graduate women attending Simmons College completed a beverage questionnaire, and a subsample of 41 women completed a 3-day food diary. Mean reported GCB consumption was 2.5 times/week for the entire sample and 7 times/week for the food diary subsample. A comparison of GCB consumers and nonconsumers indicated that GCB drinkers had a 206 kcal/day higher intake (P=.250) and a 32 g higher sugar intake than nonconsumers (P<.05). A significant percentage of college women consume GCBs, which contributes additional energy and fat to dietary intake. Over time, this could potentially affect weight status.

Adult↗

PubMed2006

Analysis of amino acids and carbohydrates in green coffee.

The analysis of carbohydrates and amino acids in green coffee is of the utmost importance since these two classes of compounds act as precursors of the Maillard reaction during which the colour and aroma are formed. During the course of the Maillard reaction potentially harmful substances like acrylamide or 5-hydroxymethyl-furfural accrue as well. The carbohydrates were analysed by anion-exchange chromatography with pulsed amperometric detection and the amino acids by reversed phase chromatography after derivatization with 6-amino-quinolyl-N-hydroxysuccinimidyl carbamate and fluorescence detection. Both methods had to be optimized to obtain a sufficient resolution of the analytes for identification and quantification. Sucrose is the dominant carbohydrate in green coffee with a concentration of up to 90 mg/g (mean = 73 mg/g) in arabica beans and significantly lower amounts in robusta beans (mean=45 mg/g). Alanine is the amino acid with the highest concentration (mean = 1200 microg/g) followed by asparagine (mean = 680 microg/g) in robusta and 800 microg/g and 360 microg/g in arabica respectively. In general, the concentration of amino acids is higher in robusta than in arabica.

Amino Acids↗