Coffee Science Alert n° 22
January 2009
AGRONOMY
Proximity to forests drives bird conservation value of coffee plantations: implications for certification
Anand, M. O.; Krishnaswamy, J.; Das, A.
Widespread loss of primary habitat in the tropics has led to increased interest in production landscapes for biodiversity conservation. In the Western Ghats biodiversity hotspot in India, shade coffee plantations are located in close proximity to sites of high conservation value: protected and unprotected forests. Coffee is grown here under a tree canopy that may be dominated by native tree species or by nonnative species, particularly silver oak (Grevillea robusta). We investigated the influence of properties at the local scale and the landscape scale in determining bird communities in coffee plantations, with particular emphasis on species of conservation priority. We used systematic point counts in 11 coffee plantation sites and analyzed data in a randomized linear modeling framework that addressed spatial autocorrelation. Greater proportion of silver oak at the local scale and distance to contiguous forests at the landscape scale were implicated as factors most strongly driving declines in bird species richness and abundance, while increased basal area of native tree species, a local-scale variable, was frequently related to increased bird species richness and abundance. The influence of local-scale variables increased at greater distances from the forest. Distance to forests emerged as the strongest predictor of declines in restricted-range species, with 92% reduction in the abundance of two commonly encountered restricted-range species (Pompadour Green Pigeon and Yellow-browed Bulbul) and a 43% reduction in richness of bird species restricted to Indian hill forests within 8 km of forests. Increase in proportion of silver oak from 33% to 55% was associated with 91% reduction in the abundance of one commonly encountered restricted-range species (Crimson-fronted Barbet). One conservation strategy is providing incentives to grow coffee in a biodiversity-friendly manner. One implication of our study is that plantations located at varying distances to the forest cannot be compared fairly for biodiversity friendliness by existing certification methodology. Another is that conservation of existing forests at the landscape scale is essential for maintaining higher biodiversity in coffee plantations. Incentive schemes that promote conservation of remnant forests at the landscape scale and biodiversity-friendly practices locally and that relate to coffee communities as a whole rather than individual planters are likely to be more effective .
Source : Ecol Appl 2008 vol.18 (7), pp 1754 - 1763
An experimental study of habitat selection by birds in a coffee plantation
Cruz-Angon, A.; Sillett, T. S.; Greenberg, R.
Unique components of tropical habitats, such as abundant vascular epiphytes, influence the distribution of species and can contribute to the high diversity of many animal groups in the tropics. However, the role of such features in habitat selection and demography of individual species has not been established. Understanding the mechanisms of habitat selection requires both experimental manipulation of habitat structure and detailed estimation of the behavioral and demographic response of animals, e.g., changes in movement patterns and survival probabilities. Such studies have not been conducted in natural tropical forest, perhaps because of high habitat heterogeneity, high species diversity, and low abundances of potential target species. Agroforestry systems support a less diverse flora, with greater spatial homogeneity which, in turn, harbors lower overall species diversity with greater numerical dominance of common species, than natural forests. Furthermore, agroforestry systems are already extensively managed and lend themselves easily to larger scale habitat manipulations than protected natural forest. Thus, agroforestry systems provide a good model environment for beginning to understand processes underlying habitat selection in tropical forest animals. Here, we use multistate, capture-recapture models to investigate how the experimental removal of epiphytes affected monthly movement and survival probabilities of two resident bird species (Common Bush-Tanager [Chlorospingus ophthalmicus] and Golden-crowned Warbler [Basileuterus culicivorus]) in a Mexican shade coffee plantation. We established two paired plots of epiphyte removal and control. We found that Bush-Tanagers were at least five times more likely to emigrate from plots where epiphytes were removed compared to control plots. Habitat-specific movement patterns were not detected in the warbler. However, unlike the Golden-crowned Warbler, Common Bush-Tanagers depend upon epiphytes for nest sites and (seasonally) for foraging. These dispersal patterns imply that active habitat selection based on the presence or absence of epiphytes occurs in C. ophthalmicus on our study area. Survival rates did not vary with habitat in either species. Interestingly, in both species, survival was higher in the nonbreeding season, when birds were in mixed-species flocks. Movement by Common Bush-Tanagers into areas with epiphytes occurred mostly during the breeding season, when mortality-driven opportunity was greatest.
Source : Ecology 2008 vol.89 (4), pp 921 - 927
Caffeine consumption and the risk of breast cancer in a large prospective cohort of women
Ishitani, K.; Lin, J.; Manson, J. E.; Buring, J. E.; Zhang, S. M.
Prospective data relating caffeine consumption to breast cancer risk are limited. METHODS: We evaluated the association between caffeine consumption and breast cancer risk in women enrolled in a completed cancer prevention trial. Detailed dietary information was obtained at baseline (1992-1995) from 38 432 women 45 years or older and free of cancer. During a mean follow-up of 10 years, we identified 1188 invasive breast cancer cases. RESULTS: Consumption of caffeine and caffeinated beverages and foods was not statistically significantly associated with overall risk of breast cancer. The multivariate relative risks (RRs) of breast cancer were 1.02 (95% confidence interval [CI], 0.84-1.22) for caffeine (top vs bottom quintile), 1.08 (0.89-1.30) for coffee (> or =4 cups daily vs almost never), and 1.03 (0.85-1.25) for tea (> or =2 cups daily vs almost never). However, in women with benign breast disease, a borderline significant positive association with breast cancer risk was observed for the highest quintile of caffeine consumption (RR, 1.32; 95% CI, 0.99-1.76) and for the highest category of coffee consumption (> or =4 cups daily) (1.35; 1.01-1.80); tests for interaction were marginally significant. Caffeine consumption was also significantly positively associated with risk of estrogen receptor-negative and progesterone receptor-negative breast cancer (RR, 1.68; 95% CI, 1.01-2.81) and breast tumors larger than 2 cm (1.79; 1.18-2.72).
CONCLUSIONS: These data show no overall association between caffeine consumption and breast cancer risk. The possibility of increased risk in women with benign breast disease or for tumors that are estrogen and progesterone receptor negative or larger than 2 cm warrants further study.
Source : Arch Intern Med 2008 vol. 168 (18), pp 2022 - 2031
Ecological and economic services provided by birds on Jamaican Blue Mountain coffee farms
Kellermann, J. L.; Johnson, M. D.; Stercho, A. M.; Hackett, S. C.
Coffee farms can support significant biodiversity, yet intensification of farming practices is degrading agricultural habitats and compromising ecosystem services such as biological pest control. The coffee berry borer (Hypothenemus hampei) is the world's primary coffee pest. Researchers have demonstrated that birds reduce insect abundance on coffee farms but have not documented avian control of the berry borer or quantified avian benefits to crop yield or farm income. We conducted a bird-exclosure experiment on coffee farms in the Blue Mountains, Jamaica, to measure avian pest control of berry borers, identify potential predator species, associate predator abundance and borer reductions with vegetation complexity, and quantify resulting increases in coffee yield. Coffee plants excluded from foraging birds had significantly higher borer infestation, more borer broods, and greater berry damage than control plants. We identified 17 potential predator species (73% were wintering Neotropical migrants), and 3 primary species composed 67% of migrant detections. Average relative bird abundance and diversity and
relative resident predator abundance increased with greater shade-tree cover. Although migrant predators overall did not respond to vegetation complexity variables, the 3 primary species increased with proximity to noncoffee habitat patches. Lower infestation on control plants was correlated with higher total bird abundance, but not with predator abundance or vegetation complexity. Infestation of fruit was 1-14% lower on control plants, resulting in a greater quantity of saleable fruits that had a market value of US$44-$105/ha in 2005/2006. Landscape heterogeneity in this region may allow mobile predators to provide pest control broadly, despite localized farming intensities. These results provide the first evidence that birds control coffee berry borers and thus increase coffee yield and farm income, a potentially important conservation incentive for producers.
Source : Conserv Biol 2008 vol.22 (5), pp 1177 - 1185
Effect of coffee alkaloids and phenolics on egg-laying by the coffee leaf miner Leucoptera coffeella
Magalhaes, S. T.; Guedes, R. N.; Demuner, A. J.; Lima, E. R.
The recognized importance of coffee alkaloids and phenolics mediating insect-plant interactions led to the present investigation aiming to test the hypothesis that the phenolics chlorogenic and caffeic acids and the alkaloid caffeine and some of its derivatives present in coffee leaves affect egg-laying by the coffee leaf miner Leucoptera (=Perileucoptera) coffeella (Guerin-Meneville & Perrottet) (Lepidoptera: Lyonetiidae), one of the main coffee pests in the Neotropical region. These phytochemicals were, therefore, quantified in leaves from 12 coffee genotypes and their effect on the egg-laying preference by the coffee leaf miner was assessed. Canonical variate analysis and partial canonical correlation provided evidence that increased leaf levels of caffeine favour egg-laying by the coffee leaf miner. An egg-laying preference bioassay was, therefore, carried out to specifically test this hypothesis using increasing caffeine concentrations sprayed on leaves of one of the coffee genotypes with the lowest level of this compound (i.e. Hybrid UFV 557-04 generated from a cross between Coffea racemosa Lour. and C. arabica L.). The results obtained allowed the recognition of a significant concentration-response relationship, providing support for the hypothesis that caffeine stimulates egg-laying by the coffee leaf miner in coffee leaves.
Source : Bull Entomol Res 2008 vol.98 (5), pp 483 - 489
Spatial pattern and ecological process in the coffee agroforestry system
Perfecto, I.; Vandermeer, J.
The coffee agroforestry system provides an ideal platform for the study of spatial ecology. The uniform pattern of the coffee plants and shade trees allows for the study of pattern generation through intrinsic biological forces rather than extrinsic habitat patchiness. Detailed studies, focusing on a key mutualism between an ant (Azteca instabilis) and a scale insect (Coccus viridis), conducted in a 45-ha plot in a coffee agroforestry system have provided insights into (1) the quantitative evaluation of spatial pattern of the scale insect Coccus viridis on coffee bushes, (2) the mechanisms for the generation of patterns through the combination of local satellite ant nest formation and regional control from natural enemies, and (3) the consequences of the spatial pattern for the stability of predator-prey (host-parasitoid) systems, for a key coccinelid beetle preying on the scale insects and a phorid fly parasitoid parasitizing the ant.
Source : Ecology 2008 vol.89 (4), pp 915 - 920
Biodiversity loss in Latin American coffee landscapes: review of the evidence on ants, birds, and trees
Philpott, S. M.; Arendt, W. J.; Armbrecht, I.; Bichier, P.; Diestch, T. V.; Gordon, C.; Greenberg, R.; Perfecto, I.; Reynoso-Santos, R.; Soto-Pinto, L.; Tejeda-Cruz, C.; Williams-Linera, G.; Valenzuela, J.; Zolotoff, J. M.
Studies have documented biodiversity losses due to intensification of coffee management (reduction in canopy richness and complexity). Nevertheless, questions remain regarding relative sensitivity of different taxa, habitat specialists, and functional groups, and whether implications for biodiversity conservation vary across regions.We quantitatively reviewed data from ant, bird, and tree biodiversity studies in coffee agroecosystems to address the following questions: Does species richness decline with intensification or with individual vegetation characteristics? Are there significant losses of species richness in coffee-management systems compared with forests? Is species loss greater for forest species or for particular functional groups?and Are ants or birds more strongly affected by intensification? Across studies, ant and bird richness declined with management intensification and with changes in vegetation. Species richness of all ants and birds and of forest ant and bird species was lower in most coffee agroecosystems than in forests, but rustic coffee (grown under native forest canopies) had equal or greater ant and bird richness than nearby forests. Sun coffee(grown without canopy trees) sustained the highest species losses, and species loss of forest ant, bird, and tree species increased with management intensity. Losses of ant and bird species were similar, although losses of forest ants were more drastic in rustic coffee. Richness of migratory birds and of birds that forage across vegetation strata was less affected by intensification than richness of resident, canopy, and understory bird species. Rustic farms protected more species than other coffee systems, and loss of species depended greatly on habitat specialization and functional traits. We recommend that forest be protected, rustic coffee be promoted,and intensive coffee farms be restored by augmenting native tree density and richness and allowing growth of epiphytes. We also recommend that future research focus on potential trade-offs between biodiversity conservation and farmer livelihoods stemming from coffee production.
Source : Conserv Biol 2008 vol.22 (5), pp 1093 - 1105
BIOCHEMISTRY / BIOTECHNOLOGY
Inducible nature of the enzymes involved in catabolism of caffeine and related methylxanthines
Dash, S. S.; Gummadi, S. N.
Previously isolated strain of Pseudomonas sp. has the capability of utilizing caffeine as the sole source of carbon and nitrogen and degrading caffeine at higher concentrations (>10 g In this study, an assay has been developed to study the enzymatic conversion of caffeine to subsequent methylxanthines by cell free extracts of Pseudomonas sp., the activity of which has been stabilized by use of stabilizers in the lysis buffer. Growth of the strain in various methylxanthines and later enzyme assay demonstrated that the enzyme(s) involved in degradation of caffeine and other methylxanthines were inducible in nature. The results also indicated that more than one enzyme are involved in degradation of caffeine to xanthine, which constitute the primary steps in bacterial caffeine catabolism.
Source : Microbiol. 2008 vol.48 (4), pp 227 - 233
Rare and enigmatic genera (Dunnia, Schizocolea, Colletoecema), sisters to species-rich clades: phylogeny and aspects of conservation biology in the coffee family
Rydin, C.; Razafimandimbison, S. G.; Bremer, B.
Despite extensive efforts, parts of the phylogeny of the angiosperm family Rubiaceae has not been resolved and consequently, character evolution, ancestral areas and divergence times of major radiations are difficult to estimate. Here, phylogenetic analyses of 149 taxa and five plastid gene regions show that three enigmatic genera are sisters to considerably species rich clades. The rare and endangered species Dunnia, endemic to southern Guangdong, China, is sister to a large clade in the Spermacoceae alliance; the rarely collected Schizocolea from western tropical Africa is sister to the Psychotrieae alliance; and Colletoecema from central tropical Africa is sister to remaining Rubioideae. The morphology of these taxa has been considered "puzzling". In combination with further morphological studies, our results may help understanding the apparently confusing traits of these plants. Phylogenetic, morphological, and geographical isolation of Dunnia, Schizocolea and Colletocema may indicate high genetic diversity. They are lone representatives of unique lineages and if extinct, the loss would not only mean loss of genetic diversity of a single species but of an entire lineage.
Source : Mol Phylogenet Evol 2008 vol.48 (1), pp 74 - 83
MICROBIOLOGY
Coffee pulp koji of Aspergillus sojae as stable immobilized catalyst of chlorogenate hydrolase
Adachi, O.; Ano, Y.; Akakabe, Y.; Shinagawa, E.; Matsushita, K.
Chlorogenate hydrolase (EC 3.1.1.42, CHase) was highly induced in mycelia of Aspergillus sojae AKU 3312 grown in Czapek medium containing either instant coffee powder or coffee pulp as inducer. No CHase formation was observed in the mycelia when cultivated without the inducer. CHase was purified readily from CHase-induced mycelia to high homogeneity, and the purified CHase revealed the molecular weight of 180,000 consisting of two identical subunits of 88 kDa. Equimolar quinate (QA) and caffeate (CA) were confirmed on hydrolysis of chlorogenate (CGA). The purified CHase was only useful for a laboratory scale hydrolysis of CGA. For practical QA and CA production using scaled up hydrolysis of vegetable extracts of natural CGA resources, the enzyme activity of purified CHase decreased and denatured irreversibly. Preparation of coffee pulp koji and its application to QA and CA production were proposed instead of purified CHase. When coffee pulp koji was heated at 60 degrees C for 30 min, CHase survived without any appreciable loss of enzyme activity while vegetative mycelial growth and spore germination were terminated. The heated coffee pulp koji thus prepared was effective itself as stable immobilized catalyst of CHase for QA and CA production from vegetable CGA resources such as coffee powders, coffee pulp, and others.
Source : Appl Microbiol Biotechnol vol.81 (1), pp 143 - 151
Development of a monoclonal antibody against ochratoxin A and its application in enzyme-linked immunosorbent assay and gold nanoparticle immunochromatographic strip
Liu, B. H.; Tsao, Z. J.; Wang, J. J.; Yu, F. Y.
A monoclonal antibody (mAb) specific to ochratoxin A (OTA) was produced from a stable hybridoma cell line, 9C9H9, generated by the fusion of P3/NS1/1-AG4-1 myeloma cells with spleen cells isolated from a BALB/c mouse immunized with OTA-keyhole limpet hemocyanin. The 9C9H9 mAb belongs to the immunoglobulin G1 (kappa chain) isotype. A competitive direct enzyme-linked immunosorbent assay (cdELISA) and a competitive indirect ELISA were established for antibody characterization. The concentrations causing 50% inhibition of binding of OTA-horseradish peroxidase to the antibody by OTA, OTB, and OTC were found to be 0.32, 0.17, and 0.28 ng/mL, respectively, in the cdELISA. A sensitive and rapid mAb-based gold nanoparticle immunochromatographic strip was also developed using this mAb. This strip has a detection limit of 5 ng/mL for OTA and can be completed in 10 min. Analysis of OTA in coffee samples revealed that data obtained from immunochromatographic strip were in a good agreement with those obtained from cdELISA. The mAb-based cdELISA and immunochromatographic strip assay established in this study were sensitive and accurate for rapid screening of OTA in coffee samples.
Source : Anal Chem 2008 vol.80 (18), pp 7029 - 7035
Transmission efficiency of Xylella fastidiosa by sharpshooters (Hemiptera: Cicadellidae) in coffee and citrus
Marucci, R. C.; Lopes, J. R.; Cavichioli, R. R.
Xylella fastidiosa (Wells, Raju, Hung, Weisburg, Mandelco-Paul, and Brenner) is a bacterial pathogen transmitted by several sharpshooters in two tribes of Cicadellinae (Proconiini and Cicadellini). Here, we compared the transmission efficiency of X. fastidiosa in coffee (Coffea arabica L.) and citrus [Citrus sinensis (L.) Osbeck] by Cicadellini [Bucephalogonia xanthophis (Berg) and Dilobopterus costalimai Young] and Proconiini [Homalodisca ignorata Melichar and Oncometopia facialis (Signoret)] sharpshooters that occur in both crops. At different seasons, healthy adults of each species were submitted to a 48-h acquisition access period on citrus or coffee source plants infected with X. fastidiosa isolates that cause Citrus variegated chlorosis (CVC) and Coffee leaf scorch (CLS), respectively, and then confined on healthy seedlings of the corresponding host plant for a 48-h inoculation access period. No significant effect of inoculation season was observed when comparing infection rates of citrus or coffee plants inoculated by vectors at different times of the year. In citrus, the transmission rate by single insects
was significantly higher for H. ignorata (30%) in relation to B. xanthophis (5%) and O. facialis (1.1%), but there was no difference among vector species in coffee, whose transmission rates ranged from 1.2 to 7.2%. Comparing host plants, H. ignorata was more effective in transmitting X. fastidiosa to citrus (30%) in relation to coffee (2.2%), whereas the other vectors transmitted the bacterium to both hosts with similar efficiencies. Despite these variations, vector efficiency in coffee and citrus is lower than that reported in other hosts.
Source : J Econ Entomol 2008 vol.101 (4), pp 1114 - 1121
Isolation and molecular characterization of Xylella fastidiosa from coffee plants in Costa Rica
Montero-Astua, M.; Chacon-Diaz, C.; Aguilar, E.; Rodriguez, C. M.; Garita, L.; Villalobos, W.; Moreira, L.; Hartung, J. S.; Rivera, C.
Coffee plants exhibiting a range of symptoms including mild to severe curling of leaf margins, chlorosis and deformation of leaves, stunting of plants, shortening of internodes, and dieback of branches have been reported since 1995 in several regions of Costa Rica's Central Valley. The symptoms are referred to by coffee producers in Costa Rica as "crespera" disease and have been associated with the presence of the bacterium Xylella fastidiosa. Coffee plants determined to be infected by the bacterium by enzyme linked immunosorbent assay (ELISA), were used for both transmission electron microscopy (TEM) and for isolation of the bacterium in PW broth or agar. Petioles examined by TEM contained rod-shaped bacteria inside the xylem vessels. The bacteria measured 0.3 to 0.5 mum in width and 1.5 to 3.0 mum in length, and had rippled cell walls 10 to 40 nm in thickness, typical of X. fastidiosa. Small, circular, dome-shaped colonies were observed 7 to 26 days after plating of plant extracts on PW agar. The colonies were comprised of Gram-negative rods of variable length and a characteristic slight longitudinal bending. TEM of the isolated bacteria showed characteristic rippled cell walls, similar to those observed in plant tissue. ELISA and PCR with specific primer pairs 272-l-int/272-2-int and RST31/RST33 confirmed the identity of the isolated bacteria as X. fastidiosa. RFLP analysis of the amplification products revealed diversity within X. fastidiosa strains from Costa Rica and suggest closer genetic proximity to strains from the United States of America than to other coffee or citrus strains from Brazil .
Source : J Microbiol 2008 vol.46 (5), pp 482 - 490
Succession of bacterial and fungal communities during natural coffee (Coffea arabica) fermentation
Silva, C. F.; Batista, L. R.; Abreu, L. M.; Dias, E. S.; Schwan, R. F.
Bacteria, yeasts and filamentous fungi were isolated during natural coffee processing. Bacteria were isolated in greater numbers at the beginning of the fermentation, when the moisture of the coffee beans was around 68%. Gram-positive bacteria represented 85.5% of all bacteria isolated, and Bacillus was the predominant genus (51%). Gram-negative species of the genera Serratia, Enterobacter and Acinetobacter were also found. Approximately 22% of 940 randomly chosen isolates of microorganisms were yeasts. Debaryomyces (27%), Pichia (18.9%) and Candida (8.0%) were the most commonly found genera, and these three genera tended to appear more often as the fruit was fermented and dried. Aspergillus was the most abundant genus besides Penicillium, Fusarium and Cladosporium, with 42.6% of the total fungi isolates. The genera and species identified included members known to have pectinase and cellulase activities. Of the 10 organic acids analyzed and quantified in coffee beans, acetic and lactic acids may have been generated by microbial activity. Butyric acid was not detected in any sample.
Source : Food Microbiol 2008 vol.25 (8), pp 951 - 957
PROCESSING
Near infrared spectroscopy: an analytical tool to predict coffee roasting degree
Alessandrini, L.; Romani, S.; Pinnavaia, G.; Rosa, M. dalla
Use of NIR spectroscopy with chemometrics to classify coffee beans according to their degree of roasting (as determined from wt. loss, density and moisture content measurements) was investigated. NIR spectra generated for green coffee beans and coffee beans roasted to varying degrees were analysed using partial least squares regression to produce separate calibration and validation models. The ability of the models to predict wt. loss, density and moisture content of coffee beans from their spectra was evaluated. Results show that root mean square errors for the predictions were in the range 0.02-1.23%. Correlation coeff. (r) for measured vs. predicted results were in the range 0.92-0.98.
Source : Analytica Chimica Acta 2008 vol.625 (1), pp 95 - 102
Water content of roasted coffee: impact on grinding behaviour, extraction, and aroma retention
Baggenstoss, J.; Perren, R.; Escher, F.
Effects of the water content of roasted coffee were investigated on grinding behaviour, extraction and aroma retention. Normal and long duration coffee roasting trials were carried out on an industrial scale. Different amounts of water were applied during quenching, resulting in water contents in the range 2.3-8.8 g/100 g wb. Coffees were ground immediately after cooling, and after equilibration times of 6 and 24 h. Particle size distribution of ground coffees, percolation time and extraction properties were investigated on
an espresso coffee machine. Coffees ground after 24 h resting time were subjected to storage trials to determine aroma stability as influenced by water content. Coffees with high moisture contents exhibited coarser particles upon grinding, and equilibration time prior to grinding was needed for coffees with high water content to improve grinding results. Coffees with low water content did not exhibit this time dependency prior to grinding. Coffees with low water content were extracted more effectively than high moisture coffees, and percolation was slower. During open and closed storage, evolution of hexanal and sulfides was highly sensitive to water content. However, differences in evolution of other aroma compounds were found during closed storage only, where moisture content had a negative impact on aroma stability of the coffees subjected to investigation.
Source : Eur Food Res Technol 2008 vol.227 (5), pp 1357 - 1365
On-line assessment of brightness and surface kinetics during coffee roasting
Hernandez, J. A.; Heyd, B.; Trystram, G.
Coffee roasting is an important process for the development of specific organoleptic properties affecting the quality of coffee. Image analysis allows the online measurement of bean colour and surface area, but this technique is difficult to apply to coffee roasting. In this study, a method was developed to determine brightness and surface area using image analysis online, during coffee roasting. A roaster equipped with a charge-coupled device video camera, a lighting system and fibre optic spotlights was used to study Arabica green coffee beans roasted using different air temperatures. The colour and surface kinetics of the beans could be observed. The authors suggest that brightness and surface area might be suitable as indicators to ensure online quality during coffee roasting.
Source : J Food Eng. 2008 vol.87 (3), pp 314-322
More than cold coffee
Metsala, P.
This article reports on the development of a new-style energy drink with caffeine made through the fermentation of natural coffee. After an overview of the coffee market situation in Germany, the use of natural caffeine and natural antioxidants in energy drinks is reviewed, as are modern biotechnology techniques for fermentation without alcohol. The Mondicina Energy Drink has been developed by a Finnish company called Patmondia. The production and sensory aspects of the product are highlighted.
Source : Getranke Industrie 2008 vol.62 (8), pp -25 (not available on line)
Decolorization of dark brown colored coffee effluent by solar photo-Fenton reaction: Effect of solar light dose on decolorization kinetics
Tokumura, M.; Znad, H. T.; Kawase, Y.
The decolorization of dark brown colored coffee effluent by solar photo-Fenton process has been studied. Effects of accumulated solar light energy and dosage of Fenton reagents (iron and hydrogen peroxide) on the color removal have been examined. With increasing Fe dosage the rate of the decolorization increased but the enhancement was not pronounced beyond 10mgL(-1). Although addition of H(2)O(2) increased the decolorization rate up to around 1000mgL(-1) of H(2)O(2), further addition of H(2)O(2) could not enhance the color removal. At excess dosages of Fenton reagents, the color removal was not improved due to their scavenging of hydroxyl radicals. It was found that the pseudo-first order decolorization kinetic constant based on the accumulated solar energy is a sole parameter unifying solar photo-Fenton decolorization processes under the different weather conditions. The kinetic constant can be readily used to calculate the amount of solar energy required to achieve a certain degree of color removal. The mineralization was rather slower as compared with the decolorization. The decolorization capability with solar irradiation was found to be comparable to UV light irradiation. The present results suggest that abundant solar energy driving decolorization of coffee effluent by photo-Fenton reaction is highly efficient.
Source : Water Res 2008 vol.42 (18), pp 4665 - 4673
CHEMISTRY / SENSORICS
Modeling of caffeine release from crosslinked water-swellable gelatin and gelatin-maltodextrin hydrogels
Abbasi, A.; Eslamian, M.; Rousseau, D.
Research from this group has recently led to the development of a genipin-crosslinked gelatin gel that may be used as a controlled release matrix for bioactive compounds. This study presents a model that simulates the release of entrapped caffeine from the hydrogel and the ingress of water into these gels. Fick's second law of diffusion is used to describe the water penetration and bioactive release in the system. To validate the model, caffeine release experiments from the gel were carried out. The predicted bioactive release profiles are in very good agreement with experimental data at different gel compositions. The model may also be used for a wide range of bioactive molecules and hydrogels with different cylindrical dimensions.
Source : Drug Deliv. 2009 vol. 15 (7), pp 455 - 463
Determination of acrylamide during roasting of coffee
Bagdonaite, K.; Derler, K.; Murkovic, M.
Various arabica and robusta coffee beans from different regions of the world were analysed for acrylamide after roasting in a laboratory roaster. Due to the complex matrix and the comparably low selectivity of the LC-MS at m/z 72, acrylamide was analysed after derivatization with 2-mercaptobenzoic acid at m/z 226. Additionally, the potential precursors of acrylamide (3-aminopropionamide, carbohydrates, and amino acids) were studied. The highest amounts of acrylamide formed in coffee were found during the 1st min of roasting (3800 ng/g in robusta coffee and 500 ng/g in arabica coffee). When the roasting time was increased, concn. of acrylamide decreased. It was shown that, in particular, roasting time and temp., species of coffee, and amount of precursors in raw material had an influence on acrylamide formation. Robusta coffee contained significantly larger amounts of acrylamide (mean = 708 ng/g) than arabica coffee (mean = 374 ng/g). Asparagine is the limiting factor for acrylamide formation in coffee. 3-Aminopropionamide formation was observed in a dry model system with mixtures of asparagine with sugars (sucrose, glucose). Thermal decarboxylation and elimination of the alpha-amino group of asparagine at high temp. (>220°C) led to a measurable but low formation of acrylamide.
Source : J Agric Food Chem 2008 vol.56 (15), pp 6081 - 6086
Vibrational spectra of anhydrous and monohydrated caffeine and theophylline molecules and crystals
Balbuena, P. B.; Blocker, W.; Dudek, R. M.; Cabrales-Navarro, F. A.; Hirunsit, P.
Density functional theory and classical molecular dynamics simulations are used to investigate the vibrational spectra of caffeine and theophylline anhydrous and monohydrate molecules and those of their crystalline anhydrous and monohydrated states, with emphasis in the terahertz region of the spectra. To better understand the influence of water in the monohydrate crystal spectra, we analyze the vibrational spectra of water monomer, dimer, tetramer, and pentamer, and also those of liquid water at two different temperatures. In small water clusters, we observe the progressive addition of translational and librational modes to the terahertz region of the spectra. The water spectra predicted by rigid and flexible water models is examined with classical molecular dynamics, and the respective peaks, especially in the terahertz region, are compared with those found in the small clusters. Similar analysis done for caffeine and theophylline monohydrate molecules using density functional theory clearly shows the presence of water modes in the librational states and in the water stretching region. Molecular dynamics of caffeine and theophylline anhydrous and monohydrate crystals reveal the influence of vibrations from the molecule-molecule (caffeine or theophylline) crystal stacks and those from the water-molecule interactions found in the monohydrate molecules and new modes from molecule-molecule, water-molecule, and water-water hydrogen bonding interactions arising from collective effects in the crystal structure. Findings illustrate challenges of terahertz technology for the detection of specific substances in condensed phases.
Source : J Phys Chem A vol. 112 (41), pp 10210 - 10219
Group-type and fingerprint analysis of roasted food matrices (coffee and hazelnut samples) by comprehensive two-dimensional gas chromatography
Cordero, C.; Bicchi, C.; Rubiolo, P.
The present study is focused on the volatile fraction of roasted hazelnut and coffee samples, differing in botanical origins, morphological characteristics, and roasting treatments, selected as challenging matrices. Volatile components, sampled by headspace solid phase microextraction (HS-SPME), were analyzed by GC x GC-qMS, and separation results were adopted to classify, correlate, and/or compare samples and evaluate processing effects. The high-complexity sample profiles were interpreted through different methods: a group-type characterization, a direct fingerprint comparison, and a template matching to extract useful and consistent information, and advantages and limits of each specific approach were critically evaluated. The group-type analysis, focused on several known botanical and technological markers, enabled sample comparison and characterization based on their quali-quantitative distribution; it is highly reliable, because of the authentic standard confirmation, and extends the comparative procedure to trace and minor components. Fingerprint approaches (i.e., direct fingerprint comparison and template matching), on the other hand, extended sample comparisons and correlations to the whole volatiles offering an increased discrimination potential and improved sensitivity due to the wider analyte pattern considered. This study demonstrates the ability of comprehensive GC to further explore the complexity of roasted samples and emphasizes the advantages of, and the need for, a comprehensive and multidisciplinary approach to interpret the increased level of information provided by GC x GC separation in its full complexity.
Source : J Agric Food Chem 2008 vol.56 (17), pp 7655 - 7666
Sediments in coffee extracts: composition and control by enzymatic hydrolysis
Delgado, P. A.; Vignoli, J. A.; Siika-aho, M.; Franco, T. T.
Coffee extracts contain certain water-insoluble components, which cause sedimentation and limit their use in the production of instant coffee. This study into the suitability of various enzymes for reducing sedimentation in coffee extracts indicated that two enzymes, Rohapect B1L and Galactomannanase ACH were economically viable for commercial applications.
Source : Food Chemistry 2008 vol.110 (1), pp 168-176
Genetic diversity and correlation of bean caffeine content with cup quality and green bean physical characteristics in coffee (Coffea arabica L.)
Dessalegn, Y.; Labuschagne, M. T.; Osthoff, G.; Herselman, L.
Coffee species with low natural abundance of caffeine could be used to make reduced or low caffeine coffee. This survey describes the relationships between caffeine content and brewed coffee quality (using a panel of trained coffee tasters) for 42 Arabica genotypes from Ethiopia. Caffeine contents were between 9.1 and 13.2 g/kg and low caffeine content was correlated with poorer brewed coffee quality. However, the results suggest that is might be possible to select for acceptable-tasting low-caffeine coffee varieties by blending or plant breeding.
Source : J Science Food Agric 2008 vol.88 (10), pp 1726-1730
Structure determination of 3-O-caffeoyl-epi-gamma-quinide, an orphan bitter lactone in roasted coffee
Frank, O.; Blumberg, S.; Krumpel, G.; Hofmann, T.
Recent investigations on the bitterness of coffee as well as 5- O-caffeoyl quinic acid roasting mixtures indicated the existence of another, yet unknown, bitter lactone besides the previously identified bitter compounds 5- O-caffeoyl- muco-gamma-quinide, 3- O-caffeoyl-gamma-quinide, 4- O-caffeoyl- muco-gamma-quinide, 5- O-caffeoyl- epi-delta-quinide, and 4- O-caffeoyl-gamma-quinide. In the present study, this orphan bitter lactone was isolated from the reaction products generated by dry heating of 5- O-caffeoylquinic acid model, and its structure was determined as the previously unreported 3- O-caffeoyl-epi-gamma-quinide by means of liquid chromatography-mass spectrometry (LC-MS) and one-/two-dimensional NMR experiments. The occurrence of this bitter lactone, exhibiting a low bitter recognition threshold of 58 micromol/L, in coffee beverages could be confirmed by LC-MS/MS (negative electrospray ionization) operating in the multiple reaction monitoring mode .
Source : J Agric Food Chem 2008 vol.56 (20), pp 9581 - 9585
Isolation and characterisation of a coffee melanoidin fraction
Gniechwitz, D.; Reichardt, N.; Ralph, J.; Blaut, M.; Steinhart, H.; Bunzel, M.
Melanoidins were isolated from brewed coffee by ultrafiltration (UF) followed by hydrophobic interaction chromatography (HIC) of the various UF high-mol.-wt. (HMW) fractions. Melanoidin fractions obtained after HIC were characterized by greatly increased antioxidative activity compared with residual HMW material in UF fractions and had an intense brown colour. Melanoidin fractions contained only small amounts of releasable carbohydrates and amino acid (<6% each) and had comparable structural characteristics and mol. wt. (3-22 kDa) regardless of the UF fraction from which they were obtained. NMR studies indicated that melanoidins were rich in phenolic/aromatic/olefinic structural units. Data obtained support the hypothesis that melanoidins are HMW compounds with condensed phenolic constituents, rather than low mol. wt. chromophoric structural units bound to proteins or polysaccharides.
Source : J Science Food Agric 2008 vol.88 (12), pp 2153 - 2160
Characterization and fermentability of an ethanol high molecular weight coffee fraction
Gniechwitz, D.; Reichardt, N.; Meiss, E.; Ralph, J.; Steinhart, H.; Blaut, M.; Bunzel, M.
This work examined the content, chemical characteristics and fermentability of a high-molecular weight ethanol soluble coffee fraction. Arabinoxylans, proteins/peptides and unidentified Maillard reaction products were among the fractions that were separated. Coffee high molecular-weight ethanol soluble fraction was less fermentable by faecal bacteria than coffee soluble fibre and it produced fewer short-chain fatty acids because of its lower carbohydrate content .
Source : J Agric Food Chem 2008 vol.56 (14), pp 5960-5969
Survey on ochratoxin A in Indian green coffee destined for export
Gopinandhan, T. N.; Kannan, G. S.; Panneerselvam, P.; Velmourougane, K.; Raghuramulu, Y.; Jayarama, J.
Ochratoxin A (OTA) is a toxic metabolite, produced by Aspergillus spp. and Penicillium verrucosum, that is nephrotoxic and possibly carcinogenic to humans. The aim of this study was to evaluate OTA contamination in batches of green coffee destined for export. Analysis of 80 green coffee samples indicated that, although a high incidence (74%) of OTA contamination (0.2-13.5 ng/g) was recorded, the overall mean OTA level (2.17 ± 2.45 ng/g) was low. The highest recorded OTA concn. was 13.5 ng/g in a robusta cherry sample and only 5 samples had OTA above 5 ng/g level. The mean OTA level was higher in cherry (range: 1.63 ± 0.97-4.8 ± 3.90) than parchment (0.56 ± 0.35-1.10 ± 0.28), indicating a correlation between processing method and OTA contamination.
Source : Food Add Contam Part B Surveillance Communications 2008 vol.1 (1), pp 51 - 57
Risks and pitfalls of sensory data analysis for shelf life prediction: data simulation applied to the case of coffee
Guerra, S.; Lagazio, C.; Manzocco, L.; Barnaba, M.; Cappuccio, R.
Shelf life determination by means of sensory analysis is thought to be of paramount importance even
in the case of a microbiologically stable food. Several approaches are found in literature, both in terms of data collection and data processing. Whatever method is used, the subjectivity in the choice of some parameters for data collection and analysis can deeply influence the final result. We put in evidence some typical pitfalls that the researcher should avoid when planning the test and analysing data. A comparison between the most utilized techniques in sensory data processing for shelf life prediction is reported, taking as a fil rouge the case of coffee. In particular, a non-linear regression, a logistic regression and a survival models were applied to simulated data frames of coffee. We evaluated the influence of the choice of acceptability limits, as well as the effect of data variability and we found out that they strongly influence predictions, as well as the panel and the batch of product do. We suggest that in case of microbiologically stable food, like coffee, shelf life is not univocal and it is a choice of the company or the researcher, rather than the result of the interaction between product and consumer.
Source : LWT Food Science and Technology 2008 vol.41 (10), pp 2070 - 2078
Chemical characterisation of non-defective green Arabica and Robusta coffees by electrospray ionization-mass spectrometry (ESI-MS)
Mendonca, J. C. F.; Franca, A. S.; Oliveira, L. S.; Nunes, M.
The presence of defective beans can lead to poor quality roasted coffee and the aim of this study was to develop a method for discriminating between defective and non-defective Arabica and Robusta coffee beans prior to roasting. Electrospray ionisation-mass spectroscopy (ESI-MS) profiles are shown for non-defective, immature, light-sour, dark-sour and black coffee beans of both varieties. The significance of the results for discriminating defective and non-defective beans is discussed .
Source : Food Chem 2008 vol.111 (2), pp 490-497
Fast simultaneous analysis of caffeine, trigonelline, nicotinic acid and sucrose in coffee by liquid chromatography-mass spectrometry
Perrone, D.; Donangelo, C. M.; Farah, A.
Coffee flavour and bioactivity are affected by the content of compounds such as caffeine, trigonelline, nicotinic acid and sucrose which can vary according to species, variety, geographical origin and roasting conditions. This paper reports on the development and validation of a rapid LC-MS method for the simultaneous quantification of these compounds in different types of coffee on the market. The LC-MS method proved to be efficient, sensitive and rapid in comparison to other routine techniques.
Source : Food Chem 2008 vol.110 (4), pp 1030-1035
Risk-benefit considerations of mitigation measures on acrylamide content of foods - a case study on potatoes, cereals and coffee
Seal, C. J.; de Mul, A.; Eisenbrand, G.; Haverkort, A. J.; Franke, K.; Lalljie, S. P. D.; Mykkanen, H.; Reimerdes, E.; Scholz, G.; Somoza, V.; Tuijtelaars, S.; van Boekel, M.; van Klaveren, J.; Wilcockson, S.J.; Wilms, L.
An Expert Group was established to examine considerations for risk-benefit analysis of mitigation measures on acrylamide in commodities known to contribute significantly to acrylamide exposure, and their impact on safety, quality, nutritional and organoleptic parameters, together with the relevance of suspected side effects and their potential impact. This Group focused on the impact of mitigation on exposure scenarios and the risk to human health using multidimensional risk assessment approaches. The effects of preharvest, postharvest and processing conditions on acrylamide formation in potatoes,
cereals and coffee were evaluated, as well as the nutritional value and health benefits of consuming these commodities. The influence of mitigation was calculated using probabilistic risk-benefit modelling. A relatively small impact of mitigation measures on overall margin of exposure, particularly for high intake consumers, was observed. The usefulness of a simultaneous exposure model as a potential tool for acrylamide risk-benefit analysis was demonstrated .
Source : Brit J Nutr 2008 vol.99 (4), supplement 'Risk-benefit considerations of mitigation
New source of alpha-delta-galactosidase: germinating coffee beans
Shen, W.; Jin, Z.; Xu, X.; Zhao, J.; Deng, L.; Chen, H.
Alpha-delta-galactosidase (alpha-Gal) is an enzyme naturally occurring in plants, animal tissues, and microorganisms. In the human body a deficiency of alpha-Gal can lead to Anderson-Fabry's disease. Commercial alpha-Gal is prepared from green coffee beans (DCB), but the activity of alpha-Gal during the germination of green coffee is different. This study reports on the preparation and purification of alpha-Gal from germinating coffee beans (GCB) in order to develop a new source of this enzyme. Enzyme activities during the different germinating periods were compared with activity continuously increasing during germination, and stability of the purified extract was found to be stable after 6 weeks storage at optimal
pH.
Source : Food Chem 2008 vol.110 (4), pp 962-966
Reduction of nitrous acid to nitric oxide by coffee melanoidins and enhancement of the reduction by thiocyanate: possibility of its occurrence in the stomach
Takahama, U.; Hirota, S.
Studies have indicated that, in addition to chlorogenic acid and its isomers, other components that can reduce nitrous acid to nitric oxide are also present in coffee. This study examined the reactions of nitrous acid and coffee melanoidins simulating the mixture of coffee, saliva and gastric juice, in the presence and absence of thiocyanate. Radical concentration was increased by ferricyanide, and decreased by ascorbic acid. When coffee was ingested, melanoidins reacted with salivary nitrite and thiocyanate in the gastric lumen, producing nitric oxide.
Source : J Agric Food Chem 2008 vol.56 (12), pp 4736-4744
Characterization of headspace aroma compounds of freshly brewed arabica coffees and studies on a characteristic aroma compound of Ethiopian coffee
Akiyama, M.; Murakami, K.; Hirano, Y.; Ikeda, M.; Iwatsuki, K.; Wada, A.; Tokuno, K.; Onishi, M.; Iwabuchi, H.
A sampling method to isolate headspace volatiles of freshly brewed drip coffee using a solid-phase microextraction fiber (fiber type: divinylbenzene/carboxen/polydimethylsiloxane) in a short time (2 min) immediately after extraction has been developed. Volatile compounds and potent odorants obtained from each headspace aroma of various arabica coffee extracts (3 production countries: Ethiopia, Tanzania, and Guatemala; 3 roasting degrees for each country: L26, L23, and L18) using the sampling method were examined by gas chromatography/mass spectrometry (GC/MS) and GC/olfactometry (GC/O, CharmAnalysis). The results of principal component analysis (PCA) using the data of GC/O analysis showed that the aroma profile of Ethiopian coffee was discriminately different from those of Tanzanian coffee and Guatemalan coffee. In addition, it was suggested from the factor loading of the PCA that 4-(4'-hydroxyphenyl)-2-butanone (raspberry ketone; sweet-fruity odor) characterized the aroma profile of freshly brewed Ethiopian coffee. Therefore, the 4-(4'-hydroxyphenyl)-2-butanone was quantified in the 9 kinds of coffee extracts. Ethiopian coffee extract of the lightly roasted degree (roasting degree: L26) contained the highest amount of this component, while it was only a little over the reported threshold. In the sensory test, the headspace aromas of Tanzanian and Guatemalan coffees in which 4-(4'-hydroxyphenyl)-2-butanone was added were, respectively, discriminated from not added samples, and "sweet" odor was selected as an odor description that assessors found similarity between the added Tanzanian or Guatemalan coffee aroma and the Ethiopian coffee aroma. It was suggested that 4-(4'-hydroxyphenyl)-2-butanone made some detectable change on total aroma profile even though the added amount was only near threshold level.
Source : J Food Sci 2008 vol.73 (5), pp C335 - C346
COFFEE & HEALTH
Effects of adenosine receptor antagonists on amitriptyline-induced QRS prolongation in isolated rat hearts
Akgun, A.; Kalkan, S.; Hocaoglu, N.; Gidener, S.; Tuncok, Y.
We investigated the effects of adenosine receptor antagonists on amitriptyline-induced cardiotoxicity in isolated rat hearts. METHODS: The amitriptyline concentrations that prolonged the QRS duration more than 150% (10(-4) M) and 50-75% (5.5 x 10(-5) M) were accepted as the control groups for two experimental protocols, respectively. In the first protocol, amitriptyline (10(-4) M) was infused following pretreatment with a selective adenosine A(1) receptor antagonist, DPCPX (8-cyclopentyl-1,3-Dipropylxanthine,10(-4) to 10(-6) M) or a selective adenosine A(2a) receptor antagonist, CSC (8-3-chlorostyryl-caffeine,10(-4) to 10(-6) M). In the second protocol, amitriptyline (5.5 x 10(-5) M) was infused following pretreatment with DPCPX (10(-4) M) or CSC (10(-5) M). Left ventricular developed pressure (LVDP), dp/dt(max), QRS duration and heart rate (HR) were measured. RESULTS: In the first protocol, 10(-4) M DPCPX pretreatment shortened QRS duration at 50 minutes when compared to the control group (p < 0.05). In the second protocol, pretreatment with 10(-4) M DPCPX shortened the QRS duration at 40, 50, and 60 minutes after amitriptyline infusion when compared to the control group (p < 0.05, p < 0.01 and p < 0.05, respectively). Pretreatment with 10(-5) M CSC prolonged QRS duration at 20, 30, and 60 minutes (p < 0.05). Amitriptyline infusion following pretreatment with DPCPX or CSC did not change LVDP, dp/dt(max), or HR when compared to control in both protocols (p > 0.05). CONCLUSION: While 10(-4) M DPCPX shortened QRS prolongation, 10(-5) M CSC prolonged QRS duration in the isolated rat hearts with prolonged QRS duration induced by 5.5 x 10(-5)M amitriptyline. An adenosine A(1) receptor antagonist, DPCPX, might shorten amitriptyline-induced QRS prolongation by activating beta adrenergic receptors.
Source : Clin Toxicol (Phila) 2008 vol.46 (7), pp 677 - 685
Coffee and digestive disorders: not to blame
Andris, J.
This article discusses studies into the effects of coffee on the digestive system and concludes that there is an absence of evidence of a relationship between the two. It looks at the role of coffee in dyspepsia, its effect on the stomach and its effect on digestive transit through the colon .
Source : Health and Food 2008 vol. 90, pp 12-14 (not available on line)
Effect of caffeine and morphine on the developing pre-mature brain
Black, A. M.; Pandya, S.; Clark, D.; Armstrong, E. A.; Yager, J. Y.
Apnea of pre-maturity is common, occurring in 85% of infants born less than 34 week gestation. Oral caffeine is the most frequent form of therapy, often in conjunction with the use of intubation and intermittent ventilation. Morphine is used to reduce the pain believed to be associated with the latter. Little information is available on the effects of caffeine, morphine or their combination, on the developing brain. We determined the effect of caffeine and morphine alone and in combination of cell death on the developing brain of the rat. Cell death, measured by Fluoro-jade B and activated caspase-3, was significantly increased at 12 and 24 hour post-caffeine injection (P < 0.05) in the cortex, caudate, nucleus accumbens, hypothalamus, hippocampus and superior colliculus. No alterations were seen following morphine injection alone. However, in the thalamus, the combination of caffeine and morphine did increase cell death to a significantly greater extent than caffeine alone. Further research is required to determine the long-term pathologic and functional effects of caffeine and the combination of caffeine and morphine on the developing immature brain.
Source : Brain Res 2008 vol.1219, pp 136 - 142
Assessing caffeine exposure in pregnant women
Boylan, S. M.; Cade, J. E.; Kirk, S.-F. L.; Greenwood, D. C.; White, K.-L. M.; Shires, S.; Simpson, N.-A. B.
Studies on the effects of caffeine on health, while numerous, have produced inconsistent results. One of the most uncertain and controversial effects is on pregnancy outcome. Studies have produced conflicting results due to a number of methodological variations. The major challenge is the accurate assessment of caffeine intake. The aim of this study was to explore different methods of assessing caffeine exposure in pregnant women. 24 healthy pregnant women from the UK city of Leeds completed both a detailed questionnaire, the caffeine assessment tool (CAT) designed specifically to assess caffeine intake and a prospective 3 day food and drink diary. The women also provided 9 saliva samples over 2 consecutive days for estimation of caffeine and a metabolite (paraxanthine). Caffeine intakes from the CAT and diary showed adequate agreement (intra-class correlation coeff. of 0.5). For saliva caffeine and paraxanthine measures, the between-sample variation (within the same woman) was greater than between-woman and between-day variation. However, there was still adequate agreement between these measures and the CAT. The CAT is a valuable tool that is now being used in a large prospective study investigating caffeine's role in pregnancy outcome .
Source : British J Nutr 2008 voo.100 (4), pp 875 - 882
Caffeine stimulates ventilation in athletes with exercise-induced hypoxemiaCaffeine stimulates ventilation in athletes with exercise-induced hypoxemia
Chapman, R. F.; Stager, J. M.
Many athletes with exercise-induced hypoxemia (EIH) show an insufficient ventilatory response to exercise and low resting ventilatory responsiveness. The purpose of this project was to determine whether a moderate dosage of caffeine, a common ventilatory stimulant, could augment resting ventilatory responsiveness, exercise ventilation (V E), end-tidal O2 partial pressure (PetO2), and arterial oxyhemoglobin saturation (HbSaO2) in athletes with EIH. METHODS: Eight highly trained males
([formula: see text], 69.2 +/- 4.0 mL.[kg.min]) who demonstrated EIH at [formula: see text] (HbSaO2, 88.0 +/- 1.7%), ingested in a randomized design a placebo or caffeine (CAF, 8 mg.kg body wt) 1 h before testing. Ventilatory responsiveness at rest was assessed via the isocapnic hypoxic and hyperoxic hypercapnic ventilatory responses (HVR and HCVR, respectively). Dependent measures of metabolic variables, ventilation, and saturation were determined during progressive treadmill exercise to exhaustion. RESULTS: V E was higher at 75%, 80%, and 100% of [formula: see text] with CAF (P < 0.05). V E/V O2, PetO2, and HbSaO2 were increased at 75%, 80%, and 90% of [formula: see text] with CAF but were not different at [formula: see text] despite an increase in V e. No change in [formula: see text] was observed between treatments. HVR and HCVR were not different between the two conditions, indicating that the increased V E likely came from central stimulation or secondary effects of CAF. CONCLUSION: The failure of HbSaO2 to increase at [formula: see text] despite an increase in V E suggests that mechanisms influencing HbSaO2 other than an inadequate hyperventilatory response may operate to different degrees across individuals as [formula: see text] is approached .
Source : Med Sci Sports Exerc 2008 vol.40 (6), pp 1080 - 1086
Caffeine prevents age-associated recognition memory decline and changes brain-derived neurotrophic factor and tirosine kinase receptor (TrkB) content in mice
Costa, M. S.; Botton, P. H.; Mioranzza, S.; Souza, D. O.; Porciuncula, L. O.
The beneficial effects of caffeine on cognition are controversial in humans, whereas its benefit in rodents had been well characterized. However, most studies were performed with acute administration of caffeine and the tasks used to evaluate cognition had aversive components. Here, we evaluated adulthood administration of caffeine up to old age on recognition memory in mice using the object recognition task (ORT) and on brain-derived neurotrophic factor (BNDF) and tyrosine kinase receptor (TrkB) immunocontent in the hippocampus. Adult mice (6 months old) received either drinking water or caffeine (1 mg/mL) during 12 months. At 18 months of age both groups were tested for ORT. Our results showed that aged mice exhibited lower performance in the recognition memory compared with adults (6 months old). Furthermore, caffeine-treated mice showed similar performance to adult mice in the ORT and an improvement compared with their age-matched control mice. Caffeine also counteracted the age-related increase in BDNF and TrkB immunocontent. Our results corroborate with other studies and reinforce that caffeine consumed in adulthood may prevent recognition memory decline with aging. This preventive effect may involve a decrease in the hippocampal BDNF and TrkB immunocontent .
Source : Neuroscience 208 vol. 153 (4), pp 1071 - 1078
Identification and in vitro cytotoxicity of ochratoxin A degradation products formed during coffee roasting
Cramer, B.; Konigs, M.; Humpf, H. U.
Ochratoxin A (OTA) is a mycotoxin contaminant that can be present on raw coffee beans. It is claimed to be degraded by up to 90% during coffee roasting. The application of HPLC-diode array detection and HPLC-tandem mass spectrometry is described, to identify the chemical structure of OTA degradation products formed during roasting. OTA degradation involved isomerisation to 14-R-ochratoxin A and the decarboxylation to 14-decarboxy-ochratoxin A. A survey of coffee samples suggests that 14-R-ochratoxin A is the main degradation product. Cell cytotoxicity tests indicated that the toxicity of the degradation products was less than that of the parent mycotoxin.
Source : J Agric Food Chem 2008 vol. 56 (14), pp 5673-5681
Antioxidant activity and protective effects of green and dark coffee components against human low density lipoprotein oxidation
Gomez-Ruiz, J. A.; Ames, J. M.; Leake, D. S.
Phenolic compounds and melanoidins in brewed coffee have been shown to exhibit antioxidant activity and the aim of this study was to investigate the effects of roasting on the antioxidant potential of coffee extracts. It was found that coffees with the highest levels of brown pigments (such as Maillard reaction products) exhibited the highest peroxyl radical-scavenging activity and also protected human low-density lipoprotein (LDL) against oxidation. Green-coffee extracts exhibited higher antioxidant activity than roasted coffee extracts, but this is attributed to the presence of phenolic compounds, such as chlorogenic acid, which are poorly absorbed.
Source : Eur Food Res Technol 2008 vol.227 (4), pp 1017-1024
Pharmacological application of caffeine inhibits TGF-beta-stimulated connective tissue growth factor expression in hepatocytes via PPARgamma and SMAD2/3-dependent pathways
Gressner, O. A.; Lahme, B.; Rehbein, K.; Siluschek, M.; Weiskirchen, R.; Gressner, A. M.
Epidemiological studies suggest that coffee drinking is inversely correlated with the risk of development of liver fibrosis but the molecular basis is unknown. METHODS: We investigated the pharmacological mechanisms involved in caffeine-dependent regulation of CTGF expression, an important modulator protein of fibrogenic TGF-beta, in rat hepatocytes using Western-blot, co-immunoprecipitations, reporter-gene-assays and ELISAs. RESULTS: It is demonstrated that caffeine, similar to 8-Br-cAMP, suppresses CTGF expression, decreases SMAD2 protein levels and inhibits SMAD1/3-phosphorylation. The SMAD2 level can be restored by a proteasome inhibitor. Additionally, caffeine leads to an up-regulation of PPARgamma expression, that enhances the inhibitory effect of the natural PPARgamma agonist 15-PGJ(2) on CTGF expression by inducing a dissociation of the SMAD2/3-CBP/p300-transcriptional complex.
CONCLUSIONS: We show that caffeine strongly down-modulates TGF-beta-induced CTGF expression in hepatocytes by stimulation of degradation of the TGF-beta effector SMAD 2, inhibition of SMAD3 phosphorylation and up-regulation of the PPARgamma-receptor. Long-term caffeinization might be an option for anti-fibrotic trials in chronic liver diseases .
Source : J Hepatol 2008 vol.49 (5), pp 758 - 767
Paraxanthine, the primary metabolite of caffeine, provides protection against dopaminergic cell death via stimulation of ryanodine receptor channels
Guerreiro, S.; Toulorge, D.; Hirsch, E.; Marien, M.; Sokoloff, P.; Michel, P. P.
Epidemiological evidence suggests that caffeine or its metabolites reduce the risk of developing Parkinson's disease, possibly by protecting dopaminergic neurons, but the underlying mechanism is not clearly understood. Here, we show that the primary metabolite of caffeine, paraxanthine (PX; 1, 7-dimethylxanthine), was strongly protective against neurodegeneration and loss of synaptic function in a culture system of selective dopaminergic cell death. In contrast, caffeine itself afforded only marginal protection. The survival effect of PX was highly specific to dopaminergic neurons and independent of glial cell line-derived neurotrophic factor (GDNF). Nevertheless, PX had the potential to rescue dopaminergic neurons that had matured initially with and were then deprived of GDNF. The protective effect of PX was not mediated by blockade of adenosine receptors or by elevation of intracellular cAMP levels, two pharmacological effects typical of methylxanthine derivatives. Instead, it was attributable to a moderate increase in free cytosolic calcium via the activation of reticulum endoplasmic ryanodine receptor (RyR) channels. Consistent with these observations, PX and also ryanodine, the preferential agonist of RyRs, were protective in an unrelated paradigm of mitochondrial toxin-induced dopaminergic cell death. In conclusion, our data suggest that PX has a neuroprotective potential for diseased dopaminergic neurons .
Source : Mol Pharmacol 2008 vol.74 (4), pp 980 - 989
Use of a prescribed ephedrine/caffeine combination and the risk of serious cardiovascular events: a registry-based case-crossover study
Hallas, J.; Bjerrum, L.; Stovring, H.; Andersen, M.
Ephedrine and herbal ephedra preparations have been shown to induce a small-to-moderate weight loss. Owing to reports on serious cardiovascular events, they were banned from the US market in 2004. There have been no large controlled studies on the possible association between prescribed ephedrine/caffeine and cardiovascular events in general. The authors linked data from four different sources within Statistics Denmark, using data on 257,364 users of prescribed ephedrine/caffeine for the period 1995-2002. The data were analyzed using a case-crossover technique with a composite endpoint: death outside of a hospital, myocardial infarction, or stroke. To account for effects of chronic exposure and effects in naive users, the authors performed a secondary case-control study nested within the cohort of ephedrine/caffeine ever users. Among 2,316 case subjects, 282 (12.2%) were current users of ephedrine/caffeine. The case-crossover analysis yielded an odds ratio of 0.84 (95% confidence interval: 0.71, 1.00); after adjustment for trends in ephedrine/caffeine use, it was 0.95 (95% confidence interval: 0.79, 1.16). Subgroup analyses revealed no strata with significantly elevated risk. In the case-control substudy, there was no increased risk among naive users or users with large cumulative doses. Prescribed ephedrine/caffeine was not associated with a substantially increased risk of adverse cardiovascular outcomes in this study .
Source : Am J Epidemiol 2008 vol.168 (8), pp 966 - 973
Prospective study of coffee and tea consumption in relation to risk of type 2 diabetes mellitus
Hamer, M.; Witte, D. R.; Mosdol, A.; Marmot, M. G.; Brunner, E. J.
At least fourteen cohort studies have documented an inverse association between coffee consumption and risk of type 2 diabetes. We examined the prospective association between coffee and tea consumption and the risk of type 2 diabetes mellitus among British men (n 4055) and women (n 1768) from the Whitehall II cohort. During 11.7 years follow-up there were a total of 387 incident cases of diabetes confirmed by self-report of doctor's diagnosis or glucose tolerance tests. Despite an inverse association between coffee intake and 2 h post-load glucose concentration at the baseline assessment, combined caffeinated and decaffeinated coffee (hazard ratio (HR) 0.80; 95 % CI 0.54, 1.18) or only decaffeinated coffee intake (HR 0.65; 95 % CI 0.36, 1.16) was not significantly associated with diabetes risk at follow-up after adjustment for possible confounders. There was an association between tea intake and diabetes (HR 0.66; 95 % CI 0.61, 1.22; P < 0.05) after adjustment for age, gender, ethnicity and social status, which was not robust to further adjustments. There was, however, an association between combined intake of tea and coffee (two or more cups per day of both beverage) and diabetes (HR 0.68; 95 % CI 0.46, 0.99; P < 0.05) after full adjustment. In conclusion, relatively moderate intake (more than three cups per day) of coffee and tea were not prospectively associated with incidence of type 2 diabetes although there was evidence of a combined effect. The limited range of exposure and beverage consumption according to socio-economic class may explain these conflicting findings .
Source : Br J Nutr 2008 vol.100 (5), pp 1046 - 1053
Coffee improves auditory neuropathy in diabetic mice
Hong, B. N.; Yi, T. H.; Park, R.; Kim, S. Y.; Kang, T. H.
Coffee is a widely consumed beverage and has recently received considerable attention for its possible beneficial effects. Auditory neuropathy is a hearing disorder characterized by an abnormal auditory brainstem response. This study examined the auditory neuropathy induced by diabetes and investigated the action of coffee, trigonelline, and caffeine to determine whether they improved diabetic auditory neuropathy in mice. Auditory brainstem responses, auditory middle latency responses, and otoacoustic emissions were evaluated to assess auditory neuropathy. Coffee or trigonelline ameliorated the hearing threshold shift and delayed latency of the auditory evoked potential in diabetic neuropathy. These findings demonstrate that diabetes can produce a mouse model of auditory neuropathy and that coffee consumption potentially facilitates recovery from diabetes-induced auditory neuropathy. Furthermore, the active constituent in coffee may be trigonelline.
Source : Neurosci Lett 2008 vol.441 (3), pp 302 - 306
Coffee intake and CYP1A2*1F genotype predict breast volume in young women: implications for breast cancer
Jernstrom, H.; Henningson, M.; Johansson, U.; Olsson, H.
As breast volume may be associated with heart cancer risk, we studied the relationship between breast volume, CYP1A2*1 F and coffee intake. Among healthy premenopausal non-hormone users, 3+ cups per day was associated with lower volume only in C-allele carriers (P(interaction)=0.02), which is consistent
with reports that coffee protects only C-allele carriers against breast cancer.
Source : Br J Cancer 2008 vol.99 (9), pp 1534 - 1538
Caffeine yields aneuploidy through asymmetrical cell division caused by misalignment of chromosomes
Katsuki, Y.; Nakada, S.; Yokoyama, T.; Imoto, I.; Inazawa, J.; Nagasawa, M.; Mizutani, S.
Aneuploidy has been implicated as an important step leading to various neoplasias. Although genetic factors that block aneuploidy have been the subject of intense interest, the impact of pharmacological and environmental substances on the development of aneuploidy has not been studied. Here, we show that caffeine induces aneuploidy through asymmetrical cell division. Mitotic exits of HeLa, U2OS, and primary fibroblast cells were significantly delayed by 10 mmol/L caffeine. Most caffeine-treated mitotic cells showed misalignment of chromosomes at the metaphase plates, and were arrested at prometaphase. Mitoticarrest deficient 2 (MAD2) depletion rescued the caffeine-induced delay of mitotic exit, indicating that caffeine-induced prolongation of mitosis was caused by activation of a MAD2-dependent spindle checkpoint. Enumeration of centromeres by fluorescence in situ hybridization revealed that cell division in the presence of caffeine was not symmetrical and resulted in aneuploid cell production. Most of these cells survived and underwent DNA synthesis. Our findings reveal a novel pharmacological effect of a high concentration of caffeine on genomic stability in dividing cells.
Source : Cancer Sci 2008 vol.99 (8), pp 1539 - 1545
Caffeine in children with obstructive sleep apnea
Khalil, S. N.; Maposa, D.; Ghelber, O.; Rabb, M. F.; Matuszczak, M.; Ganesan, B. A.; Tabrizi, H. K.; Chuang, A. Z.
Children with obstructive sleep apnea (OSA) have a higher rate of adverse post-extubation respiratory events, such as laryngospasm, upper airway obstruction, apnea, desaturation and/or need for re-intubation. They are overly sensitive to sedatives and narcotics. Although the etiology of OSA is primarily obstruction (mechanical or neuromuscular), a central element may contribute to OSA. Caffeine citrate has been shown to be effective in treating apnea of prematurity. This study evaluated whether the administration of caffeine benzoate to children with OSA decreases the number of children who experience adverse post-extubation respiratory events. METHODS: In a randomized, double-blind and placebo-controlled study, children with OSA scheduled for adenotonsillectomy (T&A) received either caffeine benzoate, 20 mg/kg IV, (caffeine group, n = 36) or saline (placebo group, n = 36). The primary outcome evaluated the number of children who developed adverse post-extubation respiratory events, and the secondary outcome was the incidence of those events. RESULTS: The results demonstrated the two groups differed in the number of children who developed adverse post-extubation respiratory events (p = 0.032). The overall incidence of adverse postoperative respiratory events was less in the caffeine group than the placebo group (p = 0.0196). CONCLUSION: In children with OSA scheduled for T&A, administration of caffeine benzoate, 20 mg/kg IV, decreased the number of children who developed adverse post-extubation respiratory events and decreased the overall incidence of adverse post-extubation respiratory events. PACU duration, hospital discharge time and postoperative delirium did not differ between groups.
Source : Middle East J Anesthesiol 2008 vol.19 (4), pp 885 - 899
Caffeine induces Ca2+ release by reducing the threshold for luminal Ca2+ activation of the ryanodine receptor
Kong, H.; Jones, P. P.; Koop, A.; Zhang, L.; Duff, H. J.; Chen, S. R.
Caffeine has long been used as a pharmacological probe for studying RyR (ryanodine receptor)-mediated Ca(2+) release and cardiac arrhythmias. However, the precise mechanism by which caffeine activates RyRs is elusive. In the present study, we investigated the effects of caffeine on spontaneous Ca(2+) release and on the response of single RyR2 (cardiac RyR) channels to luminal or cytosolic Ca(2+). We found that HEK-293 cells (human embryonic kidney cells) expressing RyR2 displayed partial or 'quantal' Ca(2+) release in response to repetitive additions of submaximal concentrations of caffeine. This quantal Ca(2+) release was abolished by ryanodine. Monitoring of endoplasmic reticulum luminal Ca(2+) revealed that caffeine reduced the luminal Ca(2+) threshold at which spontaneous Ca(2+) release occurs. Interestingly, spontaneous Ca(2+) release in the form of Ca(2+) oscillations persisted in the presence of 10 mM caffeine, and was diminished by ryanodine, demonstrating that unlike ryanodine, caffeine, even at high concentrations, does not hold the channel open. At the single-channel level, caffeine markedly reduced the threshold for luminal Ca(2+) activation, but had little effect on the threshold for cytosolic Ca(2+) activation, indicating that the major action of caffeine is to reduce the luminal, but not the cytosolic, Ca(2+) activation threshold. Furthermore, as with caffeine, the clinically relevant, pro-arrhythmic methylxanthines aminophylline and theophylline potentiated luminal Ca(2+) activation of RyR2, and increased the propensity for spontaneous Ca(2+) release, mimicking the effects of disease-linked RyR2 mutations. Collectively, our results demonstrate that caffeine triggers Ca(2+) release by reducing the threshold for luminal Ca(2+) activation of RyR2, and suggest that disease-linked RyR2 mutations and RyR2-interacting pro-arrhythmic agents may share the same arrhythmogenic mechanism.
Source : Biochem J 2008 vol.414 (3), pp 441 - 452
Caffeine overcomes genistein-induced G2/M cell cycle arrest in breast cancer cells
Li, Z.; Liu, W.; Mo, B.; Hu, C.; Liu, H.; Qi, H.; Wang, X.; Xu, J.
Although inhibition of tumor cell growth by genistein is mediated by different types of cell cycle arrest, its regulation of genes related to the cell cycle is not clear. In this study, genistein caused a concentration-dependent growth inhibition in the hormone-independent cell line MDA-MB-435S. Flow cytometric analysis showed that genistein induced a concentration-dependent accumulation of cells in the G2/M phase of the cell cycle. Caffeine enhanced the inhibition of cell proliferation induced by genistein. Caffeine alone did not have an appreciable effect on the phases of the cell cycle, but caffeine at 3 mM completely eliminated genistein-induced G2/M cell cycle arrest. cDNA microarrays were used to investigate the mechanism of genistein-induced, caffeine-negated G2/M arrest. We identified 12 genes, which had opposite responses to genistein and caffeine treatments. Among these, 5 genes were upregulated by genistein and downregulated by caffeine; 7 genes were downregulated by genistein and upregulated by caffeine. Reversal by caffeine of genistein-induced G2/M phase arrest in breast cancer cell lines could increase their sensitivity to genistein and enhance genistein-induced inhibition of cell growth. Genes that have opposite responses to genistein and caffeine may be involved in regulation of the G2/M phase of the cell cycle.
Source : Nutr Cancer 2008 vol.60 (3), pp 382 - 388
The effects of caffeine ingestion on time trial cycling performance
Mc-Naughton, L. R.; Lovell, R. J.; Siegler, J. C.; Midgley, A. W.; Sandstrom, M.; Bentley, D. J.
The purpose of this work was to determine the effects of caffeine ingestion on cycling time trial (TT) performance in well trained male subjects. METHODS: Eight males, with the following physical characteristics (Mean +/- SD) age 30.2+/-10.1 years, height 180.3+/-7.1 cm, mass 70.4+/-5.1 kg, VO(2max) 63.6+/-4.4 mL.kg(-1)x min(-1) undertook three 1 h TT performances on a VelotronPro(R) cycle ergometer, in a double blind, random fashion. The trials were Control (C), Placebo (Pl) and Caffeine (CAF). The CAF and Pl were given 60 min prior to exercise in a dose of 6 mg.kg(-1) body mass. Prior to ingestion, 60 min post ingestion, and at the end of the TT, subjects gave 10 mL of venous blood which was analysed for lactate, glucose, and free fatty acids. Expired air was collected throughout each test by indirect calorimetry. RESULTS: The cyclists rode significantly further in CAF trial (28.11+/-1.32 km) than they did in the C (26.69+/-1.5 km, P<0.03) or Pl (27.0+/-1.5 km, P<0.03) trials. No significant differences were seen between C and Pl trials (P>0.88). No differences between C and Pl were seen in heart rate data throughout the TT (p>0.05). The free fatty acid (FFA) concentrations were significantly higher in the CAF trials both post ingestion (P<0.005) and post exercise (P<0.0001) than either C or Pl trials.
CONCLUSION: We concluded that performance was improved possibly based upon a greater reliance on fat metabolism, as indicated by increased FFA and a lower respiratory exchange ratio (RER).
Source : J Sports Med Phys Fitness 2008 vol.48 (3), pp 320 - 325
Comparing the benefits of caffeine, naps and placebo on verbal, motor and perceptual memory
Mednick, S. C.; Cai, D. J.; Kanady, J.; Drummond, S. P.
Caffeine, the world's most common psychoactive substance, is used by approximately 90% of North Americans everyday. Little is known, however, about its benefits for memory. Napping has been shown to increase alertness and promote learning on some memory tasks. We directly compared caffeine (200mg) with napping (60-90min) and placebo on three distinct memory processes: declarative verbal memory, procedural motor skills, and perceptual learning. In the verbal task, recall and recognition for unassociated words were tested after a 7h retention period (with a between-session nap or drug intervention). A second, different, word list was administered post-intervention and memory was tested after a 20min retention period. The non-declarative tasks (finger tapping task (FTT) and texture discrimination task (TDT)) were trained before the intervention and then retested afterwards. Naps enhanced recall of words after a 7h and 20min retention interval relative to both caffeine and placebo. Caffeine significantly impaired motor learning compared to placebo and naps. Napping produced robust perceptual learning compared with placebo; however, naps and caffeine were not significantly different. These findings provide evidence of the limited benefits of caffeine for memory improvement compared with napping. We hypothesize that impairment from caffeine may be restricted to tasks that contain explicit information; whereas strictly implicit learning is less compromised.
Source : Behav Brain Res 2008 vol.193 (1), pp 79 - 86
Neonatal caffeine induces sex-specific developmental plasticity of the hypoxic respiratory chemoreflex in adult rats
Montandon, G.; Bairam, A.; Kinkead, R.
Caffeine is widely used to treat apneas of prematurity during the neonatal period; however, the potential consequences of administering a neonatal caffeine treatment (NCT) during a critical period for respiratory control development are unknown. The present study therefore determined whether NCT in rats alters the hypoxic respiratory chemoreflex measured at adulthood. Newborn rats received either caffeine (15 mg/kg) or water (control) each day from postnatal day 3 to 12. The ventilatory response to a hypoxic challenge (inspired O(2) fraction = 0.12) was first evaluated in awake adult female and male rats using whole body plethysmography. Results showed that NCT increased the initial phase of the breathing frequency response to hypoxia in males only. This result was confirmed in anesthetized and artificially ventilated adult male rats where NCT also increased the phrenic burst frequency response to hypoxia. RT-PCR assessment of mRNA encoding for adenosine A(1A) and A(2A) receptors, dopamine D(2) receptors, and
tyrosine hydroxylase in the rat carotid bodies showed that NCT enhanced mRNA expression levels of adenosine A(2A), dopamine D(2) receptors, and tyrosine hydroxylase of males but not females. Subsequent experiments on awake male rats showed that injection of the adenosine A(2A) receptor antagonist ZM2413855 (1 mg/kg ip) before ventilatory measurements abolished, in NCT rats, the enhanced respiratory frequency response observed during the early phase of hypoxia. We propose that NCT elicits a sex-specific increase in the hypoxic respiratory chemoreflex, which is related, at least partially, to an enhancement in adenosine A(2A) receptors in the rat carotid body .
Source : Am J Physiol Regul Integr Comp Physiol 2008 vol.295 (3), pp R922 - R934
fee, tea, and incident type 2 diabetes: the Singapore Chinese Health Study
Odegaard, A. O.; Pereira, M. A.; Koh, W. P.; Arakawa, K.; Lee, H. P.; Yu, M. C.
Increasing coffee intake was inversely associated with risk of type 2 diabetes in populations of European descent; however, data from high-risk Asian populations are lacking as are data on tea intake in general. OBJECTIVE: We investigated the prospective associations between intakes of coffee, black tea, and green tea with the risk of type 2 diabetes in Singaporean Chinese men and women. DESIGN: We analyzed data from 36 908 female and male participants in the Singapore Chinese Health Study aged 45-74 y in 1993-1998 who had multiple diet and lifestyle measures assessed and then were followed up between 1999 and 2004. We used Cox regression models to investigate the association of baseline coffee and tea intakes with incident type 2 diabetes during follow-up, with adjustment for a number of possible confounding or mediating variables. RESULTS: In multivariate models participants reporting > or =4 cups of coffee/d had a 30% reduction in risk of diabetes [relative risk (RR): 0.70; 95% CI: 0.53, 0.93] compared with participants who reported nondaily consumption. Participants reporting > or =1 cup of black tea/d had a suggestive 14% reduction in risk of diabetes (RR: 0.86; 95% CI: 0.74, 1.00) compared with participants who reported 0 cups/d, and we observed no association with green tea. CONCLUSION: Regular consumption of coffee and potentially black tea, but not green tea, is associated with lower risk of type 2 diabetes in Asian men and women in Singapore.
Source : Am J Clin Nutr vol.88 (4), pp 979 - 985
The combined effects of L-theanine and caffeine on cognitive performance and mood
Owen, G. N.; Parnell, H.; Bruin, E.-A. de; Rycroft, J. A.
Black tea is traditionally associated with relaxation and refreshment, the active components associated with this revitalizing effect being caffeine and L-theanine. This study examined the effects of 50 mg caffeine with and without 100 mg L-theanine on cognitive performance and mood were studied in healthy volunteers using iced tea as the vehicle for administration. The effects of these treatments on word recognition, rapid visual information processing, critical flicker fusion threshold, attention switching and mood were compared to placebo in 27 participants. Performance was measured at baseline and again 60 and 90 min after each treatment (separated by a 7-day washout). Caffeine improved subjective
alertness at 60 min and accuracy on the attention-switching task at 90 min. The L-theanine and caffeine combination improved both speed and accuracy of performance of the attention-switching task at 60 min, and reduced susceptibility to distracting information in the memory task at both 60 and 90 min. These results replicate previous evidence which suggests that L-theanine and caffeine in combination are beneficial for improving performance on cognitively demanding tasks.
Source : Nutritional Neuroscience 2008 vol. 11 (4), pp 193 - 198
Maternal caffeine ingestion during gestation and lactation influences respiratory adaptation to acute alveolar hypoxia in newborn rats and adenosine A(2A) and GABA(A) receptor mRNA transcription
Picard, N.; Guenin, S.; Larnicol, N.; Perrin, Y.
Caffeine is a widely used psychostimulant freely crossing the placental barrier. At the doses usually absorbed, it acts as an antagonist of both A(1) and A(2A) adenosine receptors. Pregnant women are generally not advised to limit their caffeine consumption and thus expose their progeny to the drug during the whole of gestation and lactation. The possibility that such caffeine exposure may have long-term consequences on brain development has led to several behavioral investigations on animal models. Despite the crucial role played by adenosine receptor systems in neonatal breathing control, few studies in vitro have been concerned with the consequences of maternal caffeine absorption on breathing, and none in the unrestrained intact animal. The present investigation analyzed the influence of caffeine exposure via placental and milk transfer on resting ventilation and on the response to moderate alveolar hypoxia of 0 to 2-day-old newborn rat (P0-P2) together with the possible underlying mechanisms. Dams absorbed caffeine (46+/-3 mg/kg/day) via drinking fluid (0.2 g/L) throughout gestation, in conditions mimicking moderate human consumption. Caffeine exposure did not significantly affect basal respiratory parameters. In contrast, it attenuated both the early increase and the secondary decrease in ventilation triggered by moderate alveolar hypoxia (11% O(2) inhaled). The abolition of Fos protein expression evoked by hypoxia suggested that caffeine exposure may decrease the activity of O(2)-sensing peripheral chemoreceptor pathway. From real-time PCR data, those functional alterations were associated to increases in A(2A) adenosine receptor and alpha2 GABA(A) receptor subunit mRNAs in the medulla. This indicates that, even at moderate doses, maternal caffeine consumption may induce a series of subtle
developmental alterations that may affect modulation of breathing control in the neonate in pathological situations such hypoxia.
Source : Neuroscience 2008 vol.156 (3), pp 630 - 639
The relationship between caffeine and blood pressure in preadolescent African American girls
Reddy, J. G.; Ebbert, J. O.; Klesges, L. M.; Enders, F. T.; Klesges, R. C.; Lanctot, J. Q.; McClanahan, B. S.
While high caffeine consumption has been shown to be associated with increased blood pressure in controlled experiments, the relationship between caffeine consumption and blood pressure in preadolescent (ages 6-11 years) and adolescent (ages 12-19 years) children has not been well studied. The primary objective of this study was to assess the cross-sectional relationship between caffeine intake and blood pressure in 8- to 10-year-old African American girls who eat an unrestricted diet. METHODS: Demographic, 24-hour dietary recall, and blood pressure data collected at baseline from 303 African American girls aged 8-10 years in the Girls health Enrichment Multisite Studies (GEMS) cohort were analyzed by using linear and multiple regression models. RESULTS: Dietary caffeine intake was not associated with either systolic or diastolic blood pressure (P=.33 and P=.36, respectively). However, consistent with the literature, height and body mass index were each positively and independently associated with systolic blood pressure (both P<.0001). Height and amount of sodium intake were positively associated with diastolic blood pressure (P=.01 and P=.02, respectively). CONCLUSIONS: Dietary caffeine intake in low amounts is not associated with elevated blood pressure in 8- to 10-year-old African American girls who eat an unrestricted diet.
Source : Ethn Dis 2008 vol.18 (3), pp 283 - 288 (not available on line)
Prospective study of coffee consumption and risk of Parkinson\'s disease
Saaksjarvi, K.; Knekt, P.; Rissanen, H.; Laaksonen, M. A.; Reunanen, A.; Mannisto, S.
This study aimed to examine the prediction of coffee consumption on the incidence of Parkinson's disease. The study population comprised 6710 men and women, aged 50-79 yr and free from Parkinson's disease at the baseline. At baseline, enquiries were made about coffee consumption in a self-administered questionnaire as the average number of cups per day. During a 22-yr follow-up, 101 incident cases of Parkinson's disease occurred. Parkinson's disease cases were identified through a nationwide registry of patients receiving medication reimbursement, which is based on certificates from neurologist. Results showed that after adjustments for age, sex, marital status, education, community density, alcohol consumption, leisure-time physical activity, smoking, body mass index, hypertension and serum cholesterol, the relative risk for subjects drinking 10 or more cups of coffee per day compared with non-drinkers was 0.26 (95% confidence interval 0.07-0.99, P-value for trend = 0.18). The association was stronger among overweight persons and among persons with lower serum cholesterol level (P-value for interaction = 0.04 and 0.03, respectively). These results support the hypothesis that coffee consumption reduces the risk of Parkinson's disease, but protective effect of coffee may vary by exposure to other factors.
Source : Eur J Clin Nutr 2008 vol.62 (7), pp 908 - 915
Modulation of cellular response to anticancer treatment by caffeine: inhibition of cell cycle checkpoints, DNA repair and more
Sabisz, M.; Skladanowski, A.
Caffeine and other methylxanthines produce multiple physiologic effects throughout the human body, many of these effects could potentially modulate the activity of anticancer therapy. Caffeine may directly interfere with drug transport to tumor cells by formation of mixed stacking complexes with polyaromatic drugs. If formed in cells, these complexes may also prevent of intercalating drugs from DNA binding and, in this way, lower their antitumor activity. Since many of potent carcinogens are polyaromatic compounds, formation of stacking complexes with carcinogens could be associated with anti-genotoxic activity of caffeine and its use in cancer chemoprevention. Caffeine has also been reported to inhibit ATM and ATR kinases which leads to the disruption of multiple DNA damage-responsive cell cycle checkpoints and greatly sensitizes tumor cells to antitumor agents which induce genotoxic stress. Caffeine may inhibit repair of DNA lesions through a direct interference with DNA-PK activity and other repair enzymes. A number of in vitro and in vivo studies demonstrated that caffeine modulates both innate and adaptive immune responses via inhibition of cyclic adenosine monophosphate (cAMP)-phosphodiesterase. Finally, another group of effects induced by caffeine is mediated through its inhibitory action on adenosine receptors. This may modulate the stability of HIF1 alpha as well as VEGF and interleukin-8 expression in tumor cells, which could have a direct impact on neovascularization of human tumors. In this review, we present different molecular mechanisms by which caffeine and other methylxanthines may directly or indirectly modulate the effect of antitumor treatment in tumor cells and in cancer patients.
Source : Curr Pharm Biotechnol 2008 vol.9 (4), pp 325 - 336
Effects of coffee bean aroma on the rat brain stressed by sleep deprivation: a selected transcript-and 2D gel-based proteome analysis
Seo, H. S.; Hirano, M.; Shibato, J.; Rakwal, R.; Hwang, I. K.; Masuo, Y.
There is limited information on the beneficial effects of coffee volatiles or aroma, and this study examined the influence of roasted coffee bean aroma on rat brain functions, and evaluated the impact of roasted coffee bean aroma on stress induced by sleep deprivation. Aroma of roasted coffee beans was given to Wistar rats, and upregulation was found for 11 genes, with downregulation for two genes in the stress with coffee group. Changes in protein profiles in samples were also examined. Identified proteins belonged to five functional categories. Roasted coffee bean aroma changed the mRNA and protein expression levels of the rat brain, providing clues to the potential antioxidant or stress-relaxation activities of coffee bean aroma.
Source : J Agric Food Chem 2008 vol.56 (12), pp 4665-4673
Coffee consumption and risk of endometrial cancer: a prospective study in Japan
Shimazu, T.; Inoue, M.; Sasazuki, S.; Iwasaki, M.; Kurahashi, N.; Yamaji, T.; Tsugane, S.
Coffee has been proposed to decrease the circulating insulin and estrogen levels, which are related to the development of endometrial cancer. However, few studies have prospectively assessed the association between coffee consumption and endometrial cancer. We conducted a population-based prospective cohort study in 53,724 Japanese women aged 40-69 years with no history of cancer at baseline in 1990¬1994. We used Cox proportional hazards regression analysis to estimate the hazard ratio (HR) and 95% confidence interval (CI) of endometrial cancer incidence in relation to coffee consumption. All reported p values are 2-tailed. During the 15-year follow-up period, we documented 117 cases of endometrial cancer. Coffee consumption was significantly associated with a decreased risk of endometrial cancer. After adjustment for age, study area, body mass index, menopausal status, age at menopause for postmenopausal women, parity, use of exogenous female hormones, smoking status and by consumption of green vegetables, beef, pork and green tea, the multivariate HRs (95% CI) of endometrial cancer in women who drank coffee </=2 days/week, 3-4 days/week, 1-2 cups/day and >/=3 cups/day were 1.00, 0.97 (0.56-1.68), 0.61 (0.39-0.97) and 0.38 (0.16-0.91), respectively (p for trend = 0.007). In contrast, green tea consumption was not significantly associated with a reduced risk of endometrial cancer (p for trend = 0.22). The inverse association between coffee consumption and risk of endometrial cancer was consistently observed in subgroup analyses stratified by potential confounders. Coffee consumption may be associated with a decreased risk of endometrial cancer.
Source : Int J Cancer 2008 vol. 123 (10), pp 2406 - 2410
Caffeine and progression of Parkinson disease
Simon, D. K.; Swearingen, C. J.; Hauser, R. A.; Trugman, J. M.; Aminoff, M. J.; Singer, C.; Truong, D.; Tilley, B. C.
Caffeine use is negatively associated with the risk of developing Parkinson disease (PD) and is protective in animal models of PD, but the relationship between caffeine intake and rate of progression of PD is unknown. We assessed this relationship using data from 2 recent clinical trials of PD. METHODS: Data were ascertained from 2 recent 1-year clinical trials that together included 413 early PD subjects who did not require symptomatic therapy at the time of study entry. Exploratory analyses compared caffeine intake with rate of progression of PD, as measured by either the likelihood of progression to the point of requiring symptomatic therapy or by change in the total Unified Parkinson Disease Rating Scale score. RESULTS: Rate of progression of PD did not differ significantly between those in the highest and lowest quartiles for caffeine use for either of the primary measures or for secondary analyses of changes in scores on the motor or activities of daily living subsections of the Unified Parkinson Disease Rating Scale. Other secondary analyses yielded variable results.
CONCLUSIONS: These data do not reveal a consistent relationship between caffeine intake and rate of progression of PD by these measures, although a larger study is required for sufficient power to more fully assess this relationship.
Source : Clin Neuropharmacol 2008 vol.31 (4), pp 189 - 196
Caffeine enhances endothelial repair by an AMPK-dependent mechanism
Spyridopoulos, I.; Fichtlscherer, S.; Popp, R.; Toennes, S. W.; Fisslthaler, B.; Trepels, T.; Zernecke, A.; Liehn, E. A.; Weber, C.; Zeiher, A. M.; Dimmeler, S.; Haendeler, J.
Migratory capacity of endothelial progenitor cells (EPCs) and mature endothelial cells (ECs) is a key prerequisite for endothelial repair after denuding injury or endothelial damage. METHODS AND RESULTS: We demonstrate that caffeine in physiologically relevant concentrations (50 to 100 micromol/L) induces migration of human EPCs as well as mature ECs. In patients with coronary artery disease (CAD), caffeinated coffee increased caffeine serum concentration from 2 micromol/L to 23 micromol/L, coinciding with a significant increase in migratory activity of patient-derived EPCs. Decaffeinated coffee neither affected caffeine serum levels nor migratory capacity of EPCs. Treatment with caffeine for 7 to 10 days in a mouse-model improved endothelial repair after denudation of the carotid artery. The enhancement of reendothelialization by caffeine was significantly reduced in AMPK knockout mice compared to wild-type animals. Transplantation of wild-type and AMPK(-/-) bone marrow into wild-type mice revealed no difference in caffeine challenged reendothelialization. ECs which were depleted of mitochondrial DNA did not migrate when challenged with caffeine, suggesting a potential role for mitochondria in caffeine-dependent migration. CONCLUSIONS: These results provide evidence that caffeine enhances endothelial cell migration and reendothelialization in part through an AMPK-dependent mechanism, suggesting a beneficial role for caffeine in endothelial repair.
Source : Arterioscler Thromb Vasc Biol 2008 vol.28 (11), pp 1967 - 1974
Hydroxyhydroquinone-free coffee: a double-blind, randomized controlled dose-response study of blood pressure
Yamaguchi, T.; Chikama, A.; Mori, K.; Watanabe, T.; Shioya, Y.; Katsuragi, Y.; Tokimitsu, I.
Coffee is rich in chlorogenic acids (CGA), whose metabolites may have beneficial effects such as anti-hypertensive effects. However, trial results concerning the effects of coffee on blood pressure (BP) are not consistent. A recent study suggested that hydroxyhydroquinone (HHQ), produced by the roasting of green coffee beans, inhibits the effect of CGA. In the present study, the dose-response for CGA in HHQ-free coffee on BP were investigated in mildly hypertensive men and women. METHODS AND RESULTS: The trial design was a double-blind, randomized controlled trial, with five study groups including, control, zero-dose, low-dose, middle-dose and high-dose. The control beverage was identical to ordinary coffee. The others contained reduced HHQ levels, compared to ordinary coffee, and the CGA were adjusted in target concentration. A total of 203 subjects were randomly allocated. Each subject drank one cup of coffee per day. The study involved a screening and a baseline observation period of 6 weeks and an intervention period of 4 weeks. BP response showed CGA has an anti-hypertensive effect in a dose-dependent manner in HHQ-free coffee, and ordinary coffee showed almost no effect. As a result, a significant correlation between BP change and the three dose-response patterns was observed (p<0.001).
CONCLUSIONS: This study demonstrates a dose-dependent decrease in BP for CGA in HHQ-free coffee.
Source : Nutr Metab Cardiovasc Dis 2008 vo/.18 (6), pp 408 - 414
Effect of caffeine on erectile function via up-regulating cavernous cyclic guanosine monophosphate in diabetic rats
Yang, R.; Wang, J.; Chen, Y.; Sun, Z.; Wang, R.; Dai, Y.
Erectile dysfunction (ED) is a common complication of diabetes mellitus. Phosphodiesterase-5 (PDE5) inhibitors, which inhibit the breakdown of intracellular cyclic guanosine monophosphate (cGMP), are used to treat diabetic ED. Caffeine, a nonselective PDE inhibitor used in our daily diet, is controversial regarding its effect on erectile function. To investigate the effect of caffeine on erectile function in diabetic rat models and explore the mechanism, male Sprague-Dawley rats were injected with streptozotocin to induce diabetes mellitus. The rats with blood glucose levels above 300 mg/dL were selected for the study. The rats were divided into 4 groups: group A (normal control rats), group B (diabetic rats treated with normal saline), group C (diabetic rats treated with caffeine, 10 mg/kg per day), and group D (diabetic rats treated with caffeine, 20 mg/kg per day). After 8 weeks of treatment, intracavernous pressure (ICP) was measured to assess erectile function. The radioimmunoassay was used to evaluate the level of cGMP in the cavernosum. The ICP and the cavernous cGMP decreased significantly in the diabetic rats compared with normal controls. An 8-week administration of caffeine at the given dosages increased the ICP and cavernous cGMP in diabetic rats. Caffeine consumption improved the erectile function of diabetic rats by up-regulating cavernous cGMP.
Source : J Androl 2008 vol.29 (5), pp 586 - 591
The Effects of BADGE and Caffeine on the Time-Course Response of Adiponectin and Lipid Oxidative Enzymes in High Fat Diet-Fed C57BL/6J Mice: Correlation with Reduced Adiposity and Steatosis
Yun, J. W.; Shin, E. S.; Cho, S. Y.; Kim, S. H.; Kim, C. W.; Lee, T. R.; Kim, B. H.
Adiponectin, which is expressed exclusively in adipose tissue, has been shown to increase fatty acid oxidation via activation of AMP-activated kinase (AMPK) and phosphorylation of acetyl CoA carboxylase (ACC). ACC phosphorylation and carnitine palmitoyl-transferase-1 (CPT1) activity have been shown to be rate controlling factors in fatty acid oxidation. In high fat diet (HFD)-induced obese mice, we analyzed the time-course of changes in the expression of adiponectin and lipid oxidative enzymes induced by treatment with bisphenol A diglycidyl ether (BADGE) or caffeine for 8 weeks, and investigated whether the changes of adiponectin and lipid oxidative enzymes expression correlated with reduced adiposity or steatosis after 8 weeks of treatment. After 8 weeks of treatment, BADGE and caffeine had reduced body weight and epididymal adipose tissue weight in mice fed HFD, and markedly reduced the number of fatty droplets in the liver. Interestingly, the expression of adiponectin and lipid oxidative enzymes significantly increased after 2 weeks of treatment. These results indicate that the expression of adiponectin and lipid oxidative enzymes in the early stages of BADGE or caffeine treatment correlated well with the long-term anti-obesity effects.
Source : Exp Anim 2008 vol.57 (5), pp 461 - 469