PROCESSING

Acrylamide in espresso coffee: Influence of species, roast degree and brew length

Alves, R. C.; Soares, C.; Casal, S.; Fernandes, J. O.; Oliveira, M. B. P. P

Espresso coffees were analysed for acrylamide contents by matrix solid-phase dispersion and GC-MS. The influence of coffee species, roast degree, and brew length were ascertained. Mean acrylamide contents of medium roasted espressos (30mL) were 1.16+or-0.25 and 2.31+or-0.43 mug for pure arabica and robusta samples, respectively. Espressos prepared from commercial blends contained an average acrylamide level of 1.26+or-0.28 mug. A 25% decrease was observed when comparing espressos prepared with medium and dark roasted coffee. The extraction efficacy of acrylamide for standard espressos of 30mL was near 80%, being only affected by brew volume, with long espressos (70mL) containing practically all acrylamide of the coffee cake (99%), almost double that of short ones (20mL). When compared with other common coffee beverages, espresso acrylamide concentration ( mug/L) was higher. However, due to the small volume per cup, it may contribute less to acrylamide ingestion.

Source: Food Chemistry.119, (3):929-934, 2010

Effect of roasting and brewing on ochratoxin A in coffee

Gopinandhan, T. N.; Kannan, G. S

Effect of roasting and filter brewing were investigated on levels of ochratoxin A (OTA) using 3 naturally contaminated and 2 artificially infected coffee bean (Coffea canephora) samples. The OTA contaminated coffee samples were subjected to roasting temp. of 180, 200 and 220 degrees C, light, medium and dark roasting levels and brewing times of 7, 15 and 20 min. They were analysed for OTA contents following an immunoaffinity column cleanup procedure coupled with HPLC. Naturally contaminated coffee samples underwent OTA reductions from 4 to 36.8% with an average of 22%. Artificially infected coffee sample showed OTA reductions from 7 to 28.3% with an average of 16.6%. The filter method of coffee brewing reduced OTA contents by 14%.

Source: Journal of Food Science & Technology.46, (5):459-462, 2009

Fungi isolation associated with coffee grains of the cv. Iapar 59 picked from the ground and trees at different harvest times

Bozza, A.; Moser Tralamazza, S.; Tadeu Reynaud, D.; Gabardo, J.; Valaski, J. C.; Marangoni, P. R.; Chapaval Pimentel, I.

Fungi were isolated from coffee beans (var. Iapar 59) and their effect on the quality of the beverage was examined. Samples were harvested from the plants and picked from the ground at different harvest times (0, 30, 60, 90 and 120 days). Fungi were isolated using the pour-plate method and identified using SEM. There was a significant difference in the absolute number of fungi found in samples from plants (5393) and those picked from the ground (1523). 7 genera were identified: Absidia, Acremonium, Aspergillus, Fusarium, Mucor, Paecilomyces and Penicillium. High levels of ochratoxin A were identified in some samples of coffee. The quality of the beverage decreased according to the harvest time and the period that the beans were left on the ground. It is concluded that in order to guarantee a better quality beverage, it is recommended that beans should not be left in their place of origin for too long before harvesting.

Source: Ciencia e Tecnologia de Alimentos.29, (3):529-534, 2009

CHEMISTRY / SENSORICS

Shelf-life testing of coffee and related products: uncertainties, pitfalls, and perspectives

Nicoli, M. C.; Calligaris, S.; Manzocco, L.

The word coffee comprises a number of different products from whole-and ground-roasted coffee to a wide variety of convenience and semi-manufactured products such as instant coffee, coffee concentrates and ready-to-drink coffee beverages. Each of these products has peculiar characteristics and thus different deteriorative mechanisms determining their shelf life. For this reason, shelf-life testing should be carefully designed by taking into account the peculiarity of the product. Despite the worldwide importance of coffee products, little data are available on their shelf life and on the relevant assessment methodologies. The aim of this article is to present uncertainties and pitfalls of coffee derivatives shelf-life testing as well as to highlight novel perspectives which allow developing future approaches for their dating. In particular, after describing the main quality decay reactions in coffee derivatives, literature data on coffee shelf life will be reviewed and methodologies for shelf-life testing of coffee derivatives critically discussed.

Source: Food Engineering Reviews.1, (2):159-168, 2009

UV-Vis spectrometric classification of coffees by SPA-LDA

Polari-Souto, U. T. C.; Coelho-Pontes, M. J.; Cirino-Silva, E.; Harrop-Galvao, R. K.; Ugulino-Araujo, M. C.; Castriani-Sanches, F. A.; Silva-Cunha, F. A.; Ribeiro-Oliveira, M. S.

UV-Vis spectrometry and chemometric techniques were used to classify aqueous extracts of Brazilian ground roast coffee with respect to type (caffeinated/decaffeinated) and conservation state (expired and non-expired shelf-life). Two classification methods were compared: soft independent modelling of class analogy (SIMCA) and linear discriminant analysis (LDA) with wavelength selection by the successive projections algorithm (SPA). The best results were obtained by SPA-LDA, which correctly classified all test samples. The classification accuracy of this model remained high (96%) even after the introduction of artificial spectral noise. These results suggest that UV-Vis spectrometry and SPA-LDA modelling provide a promising alternative for assessment of conservation state and decaffeination condition of coffee samples.

Source: Food Chemistry.119, (1):368-371, 2010

Identification of ethyl formate as a quality marker of the fermented off-note in coffee by a nontargeted chemometric approach

Lindinger, C.; Pollien, P.; Vos, R. C. H.; Tikunov, Y.; Hageman, J. A.; Lambot, C.; Fumeaux, R.; Voirol-Baliguet, E.; Blank, I.

The quality of coffee is influenced by many factors such as coffee variety, agricultural and postharvest conditions, roasting parameters and brewing. The pleasure of drinking coffee may be affected by off-notes such as burnt, green, earthy, or fermented. Their presence is related to the variety, fermentation during postharvest processing, or over-roasting of the beans. Sensory expert panels trained for the evaluation of coffee are able to detect off-notes and select coffees by well-defined quality criteria. The application of instrumental approaches detecting quality markers related to the perceived off-notes is shown to be useful to assist sensory panels. This paper describes the discovery of a new marker compound related to the fermented off-note occasionally perceived in coffees. The application of untargeted chemometric methods on volatile compounds revealed correlations between individual compounds and the sensory attribute. The new marker compound was identified as ethyl formate, which can be measured in the headspace of roasted and ground coffee by various analytical techniques including online proton transfer reaction mass spectrometry.

Source: Journal of Agricultural & Food Chemistry.57, (21):9972-9978, 2009

Odor detection of mixtures of homologous carboxylic acids and coffee aroma compounds by humans

Miyazawa, T.; Gallagher, M.; Preti, G.; Wise, P. M.

Mixture summation among homologous carboxylic acids, that is, the relationship between detection probabilities for mixtures and detection probabilities for their unmixed components, varies with similarity in carbon-chain length. The current study examined detection of acetic, butyric, hexanoic and octanoic acids mixed with 3 other model coffee aroma compounds that differ greatly from the acids in both structure and aroma character, namely, 2-hydroxy-3-methylcyclopent-2-en-1-one, furan-2-ylmethanethiol and (3-methyl-3-sulfanylbutyl) acetate. Psychometric functions were measured for both single compounds and binary mixtures (2 of 5, forced-choice method). An air dilution olfactometer delivered stimuli, with vapour-phase calibration using GC-MS . Across the 3 odorants that differed from the acids, acetic and butyric acid showed approx. additive (or perhaps even supra-additive) summation at low perithreshold concn., but subadditive interactions at high perithreshold concn. In contrast, the medium-chain acids showed subadditive interactions across a wide range of concn. Thus, carbon-chain length appears to influence not only summation with other carboxylic acids but also summation with at least some unrelated compounds.

Source: Journal of Agricultural & Food Chemistry.57, (21):9895-9901, 2009

Role of roasting conditions in the profile of volatile flavour chemicals formed from coffee beans

Moon, J. K.; Shibamoto, T.

Gas chromatography (GC) and GC-MS was used in the analysis of volatile compounds in dichloromethane extracts from green coffee beans roasted at three temperatures: 230 C for 12 minutes (light), 240 C for 14 minutes (medium), 250 C for 17 minutes and 250 C for 21 minutes (French); in this study to investigate the formation of volatile compounds during roasting. The major volatile compounds detected in each of the roasted coffee samples are reported, with furfural derivatives and furanones detected in relatively high concentrations under the mild roasting conditions. More pyridines and pyrroles, chlorogenic acid degradation products, phenols, and a lactone were formed by high roasting than by mild roasting intensities.

Source: Journal of Agricultural and Food Chemistry, 57 (13): 5823-5831, 2009

Study on the role of precursors in coffee flavor formation using in-bean experiments

Poisson, L.; Schmalzried, F.; Davidek, T.; Blank, I.; Kerler, J.

The formation of several key aroma compounds, such as 2-furfurylthiol (FFT), alkylpyrazines and diketones, was studied upon coffee roasting. The approach involved the incorporation of potential precursors in green coffee beans by means of biomimetic in-bean and spiking experiments. Both labelled and unlabelled precursor molecules were used, and the target analytes in the roasted coffee samples were characterized in terms of their isotope labelling pattern and abundance. The biomimetic in-bean experiments ruled out the 2-furaldehyde route to FFT as suggested by model studies. Furthermore, no evidence was found for the incorporation of the arabinose C5 skeleton into FFT. Pathways proposed for the formation of alkylpyrazines and diketones were confirmed, and a new mechanism is suggested for the formation of 2-ethenyl-3-ethyl-5-methylpyrazine. The role of amino acids, for example, alanine, and free sugars was substantiated. The results underscore the potential of this methodology to provide better understanding of the formation pathways occurring in complex food systems, which may be different from those obtained in model experiments.

Source: Journal of Agricultural & Food Chemistry.57, (21):9923-9931, 2009

CHEMISTRY

Interaction mechanisms between caffeine and polyphenols in infusions of Camellia sinensis leaves

Couzinet-Mossion, A.; Balayssac, S.; Gilard, V.; Malet-Martino, M.; Potin-Gautier, M.; Behra, P.

Black tea infusions of Camellia sinensis leaves were studied for the influence of water composition, especially calcium content, on the amount of extracted organic matter and on the interactions between caffeine and polyphenols. The higher the calcium content, the lower the extraction of caffeine and polyphenols in acidic media. In alkaline media, besides the calcium effect, polyphenols are oxidized. Caffeine NMR chemical shifts varied depending on the water used showing modified interactions. Using model solutions, polyphenols seem to be responsible for these changes in the case of ultra pure water, but in the case of alkaline solutions, the data in model solutions are different from tea infusions implying that other compounds should interact. Moreover, epigallocatechin gallate (EGCg) and epigallocatechin are the polyphenols interacting most strongly with caffeine in infusions and not EGCg and epicatechin gallate as thought before.

Source:  Food Chemistry.119, (1):173-181, 2010

Trigonelline is a novel phytoestrogen in coffee beans

Allred, K. F.; Yackley, K. M.; Vanamala, J.; Allred, C. D.

Trigonelline (Trig) is a niacin-related compound naturally occurring in coffee at approximately 1% of the dry matter in roasted beans. The aim of this study was to determine whether Trig alters the actions of oestradiol using proliferation of oestrogen-dependent human breast cancer (MCF-7) cells as a model system. Even at low concentrations (100 pM/L) Trig was found to stimulate MCF-7 growth, an effect which was mediated though an oestrogen receptor. It is concluded that trigonelline is a novel phytoestrogen in coffee beans.

Source: Journal of Nutrition, (October), 139 (10): 1833-1838

Caffeine content of retail market coffee in Portugal

Candeias, S. X.; Gallardo, E.; Matos, A. C.

How much caffeine does one ingest when drinking a simple cup of coffee in Portugal? The study presented herein tried to answer this question through the assessment of caffeine content of commercially available espresso coffee samples, both caffeinated and decaffeinated, using a high-performance liquid chromatography assay. Caffeine was rapidly separated from the sample matrix using a RP-18 column (250 x 4 mm i.d., 5 mum). The flow rate was 1.0 mL/min and the mobile phase consisted of water acidified with 5% of orthophosphoric acid/methanol (35:65, v/v). Caffeine was detected directly at 273 nm. The assay was validated for linearity, lower limit of quantification and limit of detection, precision, accuracy, and stability. Seventeen different brands of caffeinated coffee and six of decaffeinated coffee were analyzed. As for capsule coffee, eight caffeinated and two decaffeinated blends were analyzed. The caffeine content of caffeinated coffee varied from 53.8 +or-5.9 to 141.3 +or-5.3 mg/cup, whereas for caffeinated capsule coffee caffeine concentrations ranged from 45.0 +or-5.3 to 60.8 +or-6.2 mg/cup. As for decaffeinated coffee, caffeine concentrations ranged from 0.96 +or-0.04 to 3.9 +or-0.1 mg/cup and for decaffeinated capsule coffee from 0.93 +or-0.04 to 1.2 +or-0.1 mg/cup.

Source: Food Analytical Methods.2, (4):251-256, 2009

Survey of furan in foods and coffees from five European Union countries

Crews, C.; Roberts, D.; Lauryssen, S.; Kramer, G

Canned and jarred baby foods (n = 74), canned and jarred adult foods (n = 63) and 70 coffees sold in Belgium, Italy, Portugal, Spain and the Netherlands were analysed for their furan content using a validated automated headspace GC-MS procedure. 7 balsamic vinegars from Italy and Spain were also analysed. Results showed that all 74 baby food samples contained detectable levels of furan, with an average level of 37 ng/g. A total of 54 of 63 canned and jarred foods contained detectable furan with an average level of 24 ng/g. Levels of furan in coffee as consumed were very variable and reflected different preparation methods and coffee strengths. Over 50% of Italian samples contained >200 ng/g, while over 20% of Belgian coffees contained <21 ng/g furan. Some brews made from fine grained coffee contained much more furan than brews made from normal or coarse grained coffee. Although furan concn. were low in most instant coffees, 2 Italian products 'instant espresso' and 'instant mocha' contained approx. 150 ng/g furan. Balsamic vinegars from Spain contained 159-662 ng/g of furan; however, other samples from Spain and Italy contained only 6-25 ng/g.

Source: Food Additives & Contaminants: Part B -Surveillance Communications.2, (2):95-98, 2009

NMR reinvestigation of the caffeine-chlorogenate complex in aqueous solution and in coffee brews

D'Amelio, N.; Fontanive, L.; Uggeri, F.; Suggi-Liverani, F.; Navarini, L

Caffeine complexation by chlorogenic acid (3-caffeoylquinic acid, CAS Number [327-97-9]) in aqueous solution as well as caffeine-chlorogenate complex in freshly prepared coffee brews have been investigated by high-resolution 1H-NMR. Caffeine and chlorogenic acid self-associations have also been studied and self-association constants have been determined resorting to both classical isodesmic model and a recently introduced method of data analysis able to provide also the critical aggregation concentration (cac). Furthermore, caffeine-chlorogenate association constant was measured. For the caffeine, the average value of the self-association constant determined by isodesmic model (Ki = 7.6 +or - 0.5 M-1) is in good agreement with the average value (Ka = 10 +or-1.8 M-1) determined with the method which permits the determination of the cac (8.43 +or-0.05 mM). Chlorogenic acid shows a slight decreased tendency to aggregation with a lower average value of association constants (Ki = 2.8 +or-0.6 M-1; Ka = 3.4 +or-0.6 M-1) and a critical concentration equal to 24 +or-1 mM. The value of the association constant of the caffeine-chlorogenate complex (30 +or-4 M-1) is compatible with previous studies and within the typical range of reported association constants for other caffeine-polyphenol complexes. Structural features of the complex have also been investigated, and the complex conformation has been rediscussed. Caffeine chemical shifts comparison (monomeric, complexed, coffee brews) clearly indicates a significant amount of caffeine is complexed in beverage real system, being chlorogenate ions the main complexing agents.

Source: Food Biophysics.4, (4):321-330, 2009

Quantitative analysis of plasma caffeic and ferulic acid equivalents by liquid chromatography tandem mass spectrometry

Guy, P. A.; Renouf, M.; Barron, D.; Cavin, C.; Dionisi, F.; Kochhar, S.; Rezzi, S.; Williamson, G.; Steiling, H.

A validated method was developed for the simultaneous determination of the hydroxycinnamates caffeic acid (CA), dihydrocaffeic acid (DHCA), ferulic acid (FA), dihydroferulic acid (DHFA), and isoferulic acid (IFA) in human plasma as metabolites derived from coffee consumption. The method includes a protein precipitation step prior to enzymatic hydrolysis of the conjugated metabolites (sulfate, glucuronide, and/or ester) back to their aglycone forms. After liquid-liquid extraction, the reconstituted extract was analysed by high-performance liquid chromatography coupled to negative electrospray ionisation tandem mass spectrometry. Calibration curves were constructed from spiked human plasma samples in the range of 0¬4800nM for each of the targeted analytes. Two internal standards, 3-(4-hydroxyphenyl)-propionic acid (500nM) and 1,3-dicaffeoylquinic acid (200nM), were spiked at the beginning of the sample preparation and before analysis, respectively. Good performance data were obtained with limits of detection and quantification of the five hydroxycinnamates ranging between 1-15nM and 3-50nM, respectively. Within and between-days precisions were respectively calculated between 8-18% and 8-30% (at 50nM added initially), between 6-9% and 6-12% (at 200nM), and between 5-9% and 5-9% (at 500nM). Precision calculated from different analysts ranged from 18% to 44% (at 50nM), from 8% to 16% (at 200nM), and from 4% to 8% (at 500nM). Using this method, we determined plasma levels in humans and measured the efficiency of deconjugation using our enzymatic cocktail.

Source: Journal of Chromatography B.877, (31):3965-3974, 2009

Acrylamide concentrations in grilled foodstuffs of Turkish kitchen by high performance liquid chromatography-mass spectrometry

Kaplan, O.; Kaya, G.; Ozcan, C.; Ince, M.; Yaman, M.

For over ten years, there has been a considerable interest in determination of acrylamide in foodstuffs. It was known that both protein-rich and carbohydrates-rich foods cooked at high-temperatures can cause acrylamide formation. However, carbohydrates-rich foods such as potato chips and biscuit samples have been the common studied foods compared with protein-rich foods such as meat samples. In this study, determination of acrylamide in these two group foods was examined using HPLC-MS. For this purpose, firstly, the parameters that are thought to affect the response in the HPLC-MS analysis were optimized. The optimized conditions were found to be 0.3ml min-1 for flow rate of mobile phase, 40 mul for injection volume, 5 degrees C for column temperature and 70V for fragmentor potential. The optimized method was applied for the determination of acrylamide levels in Turkish foodstuffs including grilled meat and chicken samples, potato chips, coffee and biscuit. The obtained concentrations for all studied foods were in the range of 20-250 mug kg-1. The results showed that acrylamide concentrations highly varied depending on the kind of food samples.

Source: Microchemical Journal.93, (2):173-179, 2009

Determination of ochratoxin a in ready-to-drink coffee by immunoaffinity cleanup and liquid chromatography-tandem mass spectrometry

Noba, S.; Uyama, A.; Mochizuki, N.

We developed a simple and accurate method for determining ochratoxin A (OTA) in ready-to-drink coffee, using an immunoaffinity column for cleanup and liquid chromatography-tandem mass spectrometry (LC/MS/MS) for identification and quantification. When uniformly stable isotope-labeled OTA (U¬[(13)C(20)]-OTA) was employed as an internal standard, the recovery rate of the method was 97.3% (the spiked OTA level was 0.10 ng/mL), the repeatability (relative standard deviation) was 1.9%, and the intermediate precision (relative standard deviation) was 4.0%. The limit of quantification was 0.0065 ng/mL based on a signal-to-noise ratio in coffee of 10:1. The developed method was used for the determination of OTA in ready-to-drink coffee. A total of 30 ready-to-drink coffee samples commercially available in Japan were analyzed. OTA was detected in all of the samples at concentrations ranging from trace levels (0.0020-0.010 ng/mL) to 0.037 ng/mL. This method was shown to be useful for accurately evaluating the intake of OTA from coffee beverages.

Source:  Journal of Agricultural & Food Chemistry.57(14):6036-40, 2009

The use of stir bar sorptive extraction: a potential alternative method for the determination of furan, evaluated using two example food matrices

Ridgway, K.; Lalljie, S. P. D.; Smith, R. M.

A comparison is made between static headspace analysis and stir bar sorptive extraction (SBSE) for the quantitative determination of furan. The SBSE technique was optimised and evaluated using two example food matrices (coffee and jarred baby food). The use of the SBSE technique in most cases, gave comparable results to the static headspace method, using the method of standard additions with d4-labelled furan as an internal standard. Using the SBSE method, limits of detection down to 2 ng g-1 were achieved, with only a 1 h extraction. The method was performed at ambient temperatures, thus eliminating the possibility of formation of furan during extraction.

Source:  Analytica Chimica Acta.657, (2):169-174, 2010

A comparative study of arabinogalactan-protein isolates from instant coffee powder of Coffea arabica beans

Capek, P.; Matulova, M.; Navarini, L.; Suggi Liverani, F. A

Two arabinogalactan-protein isolates (AG1 and AG2) were obtained by extraction of instant coffee powder (prepared from roasted Coffea arabica beans) by a process developed by Wolfrom and Anderson (1967) and characterized by chemical and spectroscopy methods. Yields of AG1 and AG2 from a crude polysaccharide complex were 14.6 and 14.4%, respectively. These yields were approx. 2x lower than those previously reported for AG isolation by the Wolfrom and Anderson procedure over 40 years ago. This was attributed to stronger roasting and extraction conditions used for processing of instant coffee powder at that time. This conclusion was supported by the higher mol. wt. of newly isolated arabinogalactans AG1 and AG2 (average Mw 5200 -5400) compared with arabinogalactan isolated in the past (approx. 1800). Presence of proteins in AG1 and AG2 suggested that these polysaccharides were present in the form of arabinogalactan-protein complex. Saccharide analysis of AG1 and AG2 showed similar saccharide composition; both samples contained >85% galactose and >8% arabinose residues accompanied by smaller amounts of sugars as contaminants, which were not determined in the previous isolation. The high degree of structural similarity between AG1 and Ag2 was confirmed on the basis of 1H and 13C NMR spectra.

Source: Journal of Food & Nutrition Research.48, (2):80-86, 2009

Supercritical fluid extraction of lipids from spent coffee grounds

Couto, R. M.; Fernandes, J.; da, M. D. R. G.; Simoes, P. C.

Supercritical fluid extraction of lipids from spent coffee grounds was studied in this work. Extraction experiments were carried out with supercritical carbon dioxide at different pressure and temperature conditions to study the influence of those process parameters on the extraction rate and oil composition. Supercritical carbon dioxide extracted up to 85% of the total amount of oil of spent coffee grounds after 3 h of extraction (corresponding to a maximum yield of 15.4goil/100gdryspentcoffee). The fatty acid composition of the extracted oil showed the presence of fatty acids of C14, C16, C18, and C20 carbon chains. Palmitic (C16:0) and linoleic (C18:2) acids were the major fatty acids and comprise about 35% each of the total fatty acid content of the oil. A soxhlet extraction with n-hexane was done for comparison resulting in a maximum yield of oil of 18.3goil/100gdryspentcoffee. Finally, a diffusional model that takes into account the properties of the substrate, the solute partition between the solid and the supercritical phase, and the mass transfer coefficient and axial dispersion in the fluid phase was applied to this system and a good agreement with experimental results was obtained.

Source: Journal of Supercritical Fluids.51, (2):159-166, 2009

Influence of the surfactant bromide of cetyltrimetyl ammonium in the determination of chlorogenic acid in instant coffee and mate tea samples

de Araujo, T. A.; Cardoso, J. C.; Barbosa, A. M.; Ferreira, V. S.

In this study, two quantitative differential-pulse polarography (DPP) and square-wave voltammetry (SWV) methods were developed to determine total chlorogenic acid (CGA). Studies on this compound involve its reduction at a hanging mercury drop electrode in micellar media-a simple, fast, reliable, and sensitive method. The use of surfactant cationic cetyltrimethylammonium bromide (CTAB) was pivotal to the development of these methods, allowing for satisfactory changes in CGA reduction. The supporting electrolyte which provided the best-defined CGA determination was 0.04-mol L(-1) phosphate buffer at pH
6.0 in the presence of CTAB. Based on this use and under optimized conditions, the two new DPP and SWV methods for CGA analysis had detection limits of 2.36 x 10(-7) and 1.34 x 10(-9)mol L(-1), respectively, for a pure standard. Analysis of the standard in the presence of treated instant coffee and mate tea samples allowed for good average recovery rates, ranging from 97.06% to 105.90%.

Source: Colloids & Surfaces B: Biointerfaces.73(2):408-14, 2009

Chemometric evaluation of adulteration profile in coffee due to corn and husk by determining carbohydrates using HPAEC-PAD

Garcia, L. M. Z.; Pauli, E. D.; Cristiano, V.; Camara, C. A. P.; Scarminio, I. S.; Nixdorf, S. L.

The detection of impurities in roasted, ground coffee samples is required in order to verify the incidence of fraud. Carbohydrates content is an important variable, since variations from the original carbohydrates composition may be able to reveal the final composition of the product. Thus, use of carbohydrates composition for assessing the quality of Arabic roasted, ground coffee was investigated. Chemometric methods following a Simplex-Centroid statistical design were applied in order to verify adulteration of coffee with coffee husk, corn and a mixture of different amounts of these contaminants. This method was efficient in distinguishing the different matrixes. In pure coffee, higher concn. of galactose and mannose were present, at levels of 8.25 and 9.65% (w/w), respectively. However, in pure coffee husks, the predominant carbohydrates were mannitol (0.64%), arabinose (with 4.24%) and xylose (with 3.40%). For the corn sample, glucose was at a greater quantity (52.53% (w/w)). Models predicting the influence of the adulterants incorporated into coffee from the carbohydrates composition were obtained.

Source: Journal of Chromatographic Science.47, (9):825-832, 2009

Detection of adulterations in processed coffee with cereals and coffee husks using capillary zone electrophoresis

Nogueira, T.; do Lago, C. L.

The proposed method for the identification of adulteration was based on the controlled acid hydrolysis of xylan and starch present in some vegetable adulterants, followed by the analysis of the resulting xylose and glucose, which are the monosaccharides that compose, respectively, the two polysaccharides. The acid hydrolysis with HCl increases the ionic strength of the sample, which impairs the electrophoretic separation. Thus, a neutralization step based on anion exchange resin was necessary. The best separations were obtained in NaOH 80 mmol/L, CTAB 0.5 mmol/L, and methanol 30% v/v. Because of the high value of pH, monosaccharides are separated as anionic species in such running electrolyte. The LOQ for both monosaccharides was 0.2 g for 100 g of dry matter, which conforms to the tolerable limits.

Source: Journal of Separation Science.32(20):3507-11, 2009

. Fourier transform infrared spectroscopy for Kona coffee authentication

Wang, J.; Jun, S.; Bittenbender, H. C.; Gautz, L.; Li, Q. X.

Kona coffee, the variety of "Kona typica" grown in the north and south districts of Kona-Island, carries a unique stamp of the region of Big Island of Hawaii, U.S.A. The excellent quality of Kona coffee makes it among the best coffee products in the world. Fourier transform infrared (FTIR) spectroscopy integrated with an attenuated total reflectance (ATR) accessory and multivariate analysis was used for qualitative and quantitative analysis of ground and brewed Kona coffee and blends made with Kona coffee. The calibration set of Kona coffee consisted of 10 different blends of Kona-grown original coffee mixture from 14 different farms in Hawaii and a non-Kona-grown original coffee mixture from 3 different sampling sites in Hawaii. Derivative transformations (1st and 2nd), mathematical enhancements such as mean centering and variance scaling, multivariate regressions by partial least square (PLS), and principal components regression (PCR) were implemented to develop and enhance the calibration model. The calibration model was successfully validated using 9 synthetic blend sets of 100% Kona coffee mixture and its adulterant, 100% non-Kona coffee mixture. There were distinct peak variations of ground and brewed coffee blends in the spectral "fingerprint" region between 800 and 1900 cm(-1). The PLS-2nd derivative calibration model based on brewed Kona coffee with mean centering data processing showed the highest degree of accuracy with the lowest standard error of calibration value of 0.81 and the highest R(2) value of 0.999. The model was further validated by quantitative analysis of commercial Kona coffee blends. Results demonstrate that FTIR can be a rapid alternative to authenticate Kona coffee, which only needs very quick and simple sample preparations.

Source: Journal of Food Science.74(5):C385-91, 2009

COFFEE & HEALTH

The effect of daily caffeine use on cerebral blood flow: How much caffeine can we tolerate?

Addicott, M. A.; Yang, L. L.; Peiffer, A. M.; Burnett, L. R.; Burdette, J. H.; Chen, M. Y.; Hayasaka, S.; Kraft,
R. A.; Maldjian, J. A.; Laurienti, P. J.

Caffeine is a commonly used neurostimulant that also produces cerebral vasoconstriction by antagonizing adenosine receptors. Chronic caffeine use results in an adaptation of the vascular adenosine receptor system presumably to compensate for the vasoconstrictive effects of caffeine. We investigated the effects of caffeine on cerebral blood flow (CBF) in increasing levels of chronic caffeine use. Low (mean = 45 mg/day), moderate (mean = 405 mg/day), and high (mean = 950 mg/day) caffeine users underwent quantitative perfusion magnetic resonance imaging on four separate occasions: twice in a caffeine abstinent state (abstained state) and twice in a caffeinated state following their normal caffeine use (native state). In each state, there were two drug conditions: participants received either caffeine (250 mg) or placebo. Gray matter CBF was tested with repeated-measures analysis of variance using caffeine use as a between-subjects factor, and correlational analyses were conducted between CBF and caffeine use. Caffeine reduced CBF by an average of 27% across both caffeine states. In the abstained placebo condition, moderate and high users had similarly greater CBF than low users; but in the native placebo condition, the high users had a trend towards less CBF than the low and moderate users. Our results suggest a limited ability of the cerebrovascular adenosine system to compensate for high amounts of daily caffeine use.

Source: : Human Brain Mapping.30(10):3102-14, 2009

Assessment of intake of caffeine in random population in Riyadh and its levels in some food by HPLC

Al Faris, N. A.

Caffeine consumption was studied in 160 Saudi females of a mean age of 23 +or-3.7 yr who regularly consumed coffee and soft drinks. Consumption of <300 mg of caffeine per day was reported for the highest percentage of participants (42.5%), while 7.5% of participants consumed >2800 mg/day, the highest level of caffeine consumption. Participants consuming the highest percentages of caffeine were found to be coffee consumers, followed by soft drink consumers (93.75 and 90.63%, respectively), while tea consumers were reported to have the lowest percentage of caffeine consumption (45.63%). Caffeine consumption from coffee had the highest mean value (1599 +or-416.7) compared with the caffeine content in other foods. In relation to anthropometric measurements, there were no significant correlations between these measurements and levels of caffeine consumption, except wt. There was a significant correlation between decreasing body wt. and increasing amounts of caffeine consumed (P < 0.05). On the other hand, there was no significant correlation between hours of sleep and food consumption, and the amount of caffeine consumed (P < 0.05). There was, however, a high correlation between employment status of the participant and caffeine consumption (P > 0.05)

Source. Emirates Journal of Food & Agriculture.21, (1):21-31, 2009

Effect of coffee and tea on the glycaemic index of foods: no effect on mean but reduced variability

Aldughpassi, A.; Wolever, T. M. S.

The effect of coffee and tea on the glycaemic index (GI) of fruit leather and cheese puffs was examined in this study using the FAO/WHO protocol with white bread as the reference food. The effects of coffee and tea consumption on mean peak blood glucose increment, compared with water, and on mean GI values are discussed.

Source: British Journal of Nutrition, (May 14), 101 (9): 1282-1285

Variation in the human lipidome associated with coffee consumption as revealed by quantitative targeted metabolomics

Altmaier, E.; Kastenmueller, G.; Roemisch-Margl, W.; Thorand, B.; Weinberger, K. M.; Adamski, J.; Illig, T.; Doering, A.; Suhre, K.

The effect of coffee consumption on human health is still discussed controversially. Here, we report results from a metabolomics study of coffee consumption, where we measured 363 metabolites in blood serum of 284 male participants of the Cooperative Health Research in the Region of Augsburg study population, aged between 55 and 79 years. A statistical analysis of the association of metabolite concentrations and the number of cups of coffee consumed per day showed that coffee intake is positively associated with two classes of sphingomyelins, one containing a hydroxy-group (SM(OH)) and the other having an additional carboxy-group (SM(OH,COOH)). In contrast, long-and medium-chain acylcarnitines were found to decrease with increasing coffee consumption. It is noteworthy that the concentration of total cholesterol also rises with an increased coffee intake in this study group. The association observed here between these hydroxylated and carboxylated sphingolipid species and coffee intake may be induced by changes in the cholesterol levels. Alternatively, these molecules may act as scavengers of oxidative species, which decrease with higher coffee intake. In summary, we demonstrate strong positive associations between coffee consumption and two classes of sphingomyelins and a negative association between coffee consumption and long-and medium-chain acylcarnitines.

Source: : Molecular Nutrition & Food Research.53, (11):1357-1365, 2009

Caffeine\'s implications for women\'s health and survey of obstetrician-gynecologists\' caffeine knowledge and assessment practices

Anderson, B. L.; Juliano, L. M.; Schulkin, J.

Caffeine has relevance for women's health and pregnancy, including significant associations with spontaneous abortion and low birth weight. According to scientific data, pregnant women and women of reproductive age should be advised to limit their caffeine consumption. This article reviews the implications of caffeine for women's psychological and physical health, and presents data on obstetrician-gynecologists' (ob-gyns) knowledge and practices pertaining to caffeine. METHODS: Ob¬gyns (N = 386) who are members of the American College of Obstetricians and Gynecologists' Collaborative Ambulatory Research Network responded to a 21-item survey about caffeine. RESULTS: Although most knew that caffeine is passed through breast milk, only 24.8% were aware that caffeine metabolism significantly slows as pregnancy progresses. Many respondents were not aware of the caffeine content of commonly used products, such as espresso and Diet Coke, with 14.3% and 57.8% indicating amounts within an accurate range, respectively. Furthermore, ob-gyns did not take into account large differences in caffeine content across different caffeinated beverages with most recommending one to two servings of coffee or tea or soft drinks per day. There was substantial inconsistency in what was considered to be "high levels" of maternal caffeine consumption, with only 31.6% providing a response. When asked to indicate the risk that high levels of caffeine have on various pregnancy outcomes, responses were not consistent with scientific data. For example, respondents overestimated the relative risk of stillbirths and underestimated the relative risk of spontaneous abortion. There was great variability in assessment and advice practices pertaining to caffeine. More than half advise their pregnant patients to consume caffeine under certain circumstances, most commonly to alleviate headache and caffeine withdrawal. CONCLUSIONS: The data suggest that ob-gyns could benefit from information about caffeine and its relevance to their clinical practice. The development of clinical practice guidelines for caffeine may prove to be useful.

Source: : Journal of Women's Health.18(9):1457-66, 2009

Obesity, coffee consumption and CRP levels in postmenopausal overweight/obese women: importance of hormone replacement therapy use

Arsenault, B. J.; Earnest, C. P.; Despres, J. P.; Blair, S. N.; Church, T. S.

Obesity is associated with an inflammatory state that is often characterized by elevated plasma C-reactive protein (CRP) levels. Although coffee is broadly consumed in Western societies, few studies have examined the relationship between obesity, coffee consumption and CRP levels. This study examined the relationship between obesity, coffee consumption and variation in CRP in postmenopausal, overweight/obese women with or without hormone replacement therapy (HRT) use. This was a cross¬sectional analyses of 344 healthy sedentary, overweight/obese postmenopausal women (mean age 57.1 +or-6.4 yr and mean body mass index (BMI) = 36.1 +or-3.9 kg/m2). Plasma CRP levels were measured by a highly sensitive immunoassay that used monoclonal antibodies coated with polystyrene particles. Diet was assessed using the Food Intake and Analysis System semiquantitative food frequency questionnaire. Results demonstrated that plasma CRP was positively associated with BMI (P < 0.001) and negatively associated with coffee consumption (P <= 0.05). In women using HRT, plasma CRP was positively associated with BMI in women consuming <1 cup of coffee per month (r2 = 0.15 (P < 0.001)), 1 cup per day (0.14 (P = 0.02)) and >1 cup per day (0.12 (P = 0.03)). In women who did not use HRT, CRP was associated with BMI only in women consuming <1 cup of coffee per day (r2 = 0.16 (P < 0.001)) but not in women consuming 1 cup per day (0.06 (P = 0.10)) or >1 daily cup of coffee (0.03 (P = 0.27)). In conclusion, among overweight/obese postmenopausal women, coffee consumption is negatively associated with CRP. Coffee consumption appears to attenuate the association between BMI and CRP, but only in women not using HRT.

Source: European Journal of Clinical Nutrition.63, (12):1419-1424, 2009

Coffee and gut health

Bibiloni, R.

Evidence for beneficial effects of coffee consumption on gastrointestinal health is discussed with reference to: coffee as a source of soluble fibre and phenols; utilization of coffee fibre by specific bacterial groups in the gut; other coffee components degraded by gastrointestinal bacteria; studies demonstrating bifidogenic effects of coffee consumption; and effects of coffee on gut transit times. Findings suggest that, despite a lack of consensus on the definition of gut health, consumption of coffee or beverages containing coffee components influence microbial populations of the distal gut, in particular levels of Bifidobacterium spp.

Source: Agro Food Industry hi-tech.20, (5):12-14, 2009

Risk of breast cancer among French-Canadian women, noncarriers of more frequent BRCA1/2 mutations and consumption of total energy, coffee, and alcohol

Bissonauth, V.; Shatenstein, B.; Fafard, E.; Maugard, C.; Robidoux, A.; Narod, S.; Ghadirian, P.

Although the connection between diet, lifestyle and hormones suggests that nutritional and lifestyle factors may exert an influence in the etiology of breast cancer, it is not clear whether these factors operate in the same way in women without BRCA gene mutations. A nested case-control study was conducted in a cohort of French-Canadian women, with 560 members involving 280 nongene carriers of mutated BRCA gene affected by breast cancer and 280 nonaffected and nongene carriers of mutated BRCA gene. A validated semi-quantitative food frequency questionnaire was used to ascertain dietary intake, and a core questionnaire, to gather information on lifestyle risk factors. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated in logistic regression models. It was found that energy intake >2,057 Kcal/day was significantly and positively related to breast cancer risk (OR = 2.54; 95% CI: 1.67-3.84; p = 0.01). Women who drank more than eight cups of coffee per day had an increased risk of breast cancer: OR = 1.40 (95% CI: 1.09-2.24; p = 0.03). Subjects who drank >9 g of alcohol (ethanol) per day had an increased risk of breast cancer: OR = 1.55 (95% CI: 1.02-2.37; p = 0.04). In addition, a positive and significant association was noted between the consumption of beer, wine and spirits, and breast cancer risk. The ORs were 1.34 (95% CI: 1.28-2.11; p = 0.04) for more than two bottles of beer per week, OR = 1.16 (95% CI: 1.08-2.58; p = 0.05) for >10 oz of wine per week and OR = 1.09 (95% CI: 1.02¬2.08; p = 0.05) for >6 oz of spirit per week, respectively. Intakes of other nutrients and dietary components were not significantly associated with nongene carrier breast cancer risk. This study provides evidence that total energy intake, coffee, and alcohol consumption may play a role in breast cancer risk.

Source: Breast Journal.15 Suppl 1:S63-71, 2009

The paradox of caffeine-zolpidem interaction: a network analysis

Myslobodsky, M.

A widely prescribed and potent short-acting hypnotic, zolpidem has become the mainstay for the treatment of middle-of-the-night sleeplessness. It is expected to be antagonized by caffeine. Paradoxically, in some cases caffeine appears to slightly enhance zolpidem sedation. The pharmacokinetic and pharmacodynamic nature of this odd effect remains unexplored. The purpose of this study is to reproduce a hypothetical molecular network recruited by caffeine when co-administered with zolpidem using Ingenuity Pathway Analysis. Thus generated, network drew attention to several possible contributors to caffeine sedation, such as tachykinin precursor 1, cannabinoid, and GABA receptors. The present overview is centered on the possibility that caffeine potentiation of zolpidem sedation does not involve a centralized interaction of specific neurotransmitters, but rather is contributed by its antioxidant capacity. It is proposed that by modifying the cellular redox state, caffeine ultimately reduces the pool of reactive oxygen species, thereby increasing the bioavailability of endogenous melatonin for interaction with zolpidem. This side effect of caffeine encourages further studies of multiple antioxidants as an attractive way to potentially increasing somnolence.

Source: Current Drug Targets.10(10):1009-20, 2009

Dose-dependent effects of decaffeinated coffee on endothelial function in healthy subjects

Buscemi, S.; Verga, S.; Batsis, J. A.; Tranchina, M. R.; Belmonte, S.; Mattina, A.; Re, A.; Rizzo, R.; Cerasola, G.

Coffee is known to contain antioxidant substances whose effects may be blunted because of caffeine that may unfavourably affect the cardiovascular system. This study was designed to investigate the acute dose-dependent effects of decaffeinated coffee (DC) on endothelial function measured by the brachial artery flow-mediated dilation (FMD). A total of 15 (8 men and 7 women) healthy nonobese subjects underwent a single-blind, crossover study. Subjects ingested 1 and 2 cups of decaffeinated Italian espresso coffee in random order at 5-to 7-day intervals. Results showed that in the hour following the ingestion of 2 cups of DC, FMD increased (mean +or-s.e. of the mean; 0 min, 7.4 +or-0.7%; 30 min, 8.0 +or-0.6%; 60 min, 10.8 +or-0.8%, P < 0.001) as compared to consumption of 1 cup of DC (0 min, 6.9 +or-0.7%; 30 min, 8.4 +or-1.2%; 60 min, 8.5 +or-1.1%; 3 x 2 repeated-measures analysis of variance: P = 0.037 for time x treatment effect). Blood pressure did not differ between groups, and basal heart rate was lower in the 2-cup group at baseline and 60 min. This study demonstrated a significant acute favourable dose-dependent effect of decaffeinated espresso coffee on endothelial function. Further studies are needed to investigate the effects of chronic use of DC especially with respect to caffeinated coffee and in subjects with cardiovascular diseases.

Source: European Journal of Clinical Nutrition.63, (10):1200-1205, 2009

Sex differences in caffeine neurotoxicity following chronic ethanol exposure and withdrawal

Butler, T. R.; Smith, K. J.; Berry, J. N.; Sharrett-Field, L. J.; Prendergast, M. A.

Caffeine is a central nervous system stimulant that produces its primary effects via antagonism of the A1 and A2A adenosine receptor subtypes. Previous work demonstrated a sex difference in neurotoxicity produced by specific adenosine A1 receptor antagonism during ethanol withdrawal (EWD) in vitro that was attributable to effects downstream of A1 receptors at NMDA receptors. The current studies were designed to examine the effect of non-specific adenosine receptor antagonism with caffeine during ethanol withdrawal on hippocampal toxicity in cultures derived from male and female rats. Methods: At 5 days in vitro (DIV), half of the male and female organotypic hippocampal slice cultures were exposed to 50 mM ethanol (EtOH) in culture media for 10 days before exposure to caffeine (5, 20 and 100 muM) for the duration of a 24 h EWD period. In keeping with this timeline, the remaining ethanol-naive cultures were given media changes at 10 and 15 DIV and exposed to caffeine (5, 20 and 100 muM) for 24 h at 15 DIV. Cytotoxicity was assessed by fluorescent microscopy and quantification of propidium iodide (PI) uptake in the pyramidal cell layers of the CA1 and CA3 regions and the granule cell layer of the dentate gyrus (DG). A two-way (sex x treatment) ANOVA was conducted within each hippocampal region. Results: Twenty-four-hour withdrawal from 10-day exposure to 50 mM ethanol did not produce increased PI uptake in any hippocampal region. Caffeine exposure (5, 20 and 100 mu M) in ethanol-naive cultures did not produce toxicity in the DG or CA1 region, but 20 mu M caffeine produced modest toxicity in the CA3 region. Exposure to 20 mu M caffeine during EWD produced cytotoxicity in all hippocampal regions, though toxicity was sex-dependent in the DG and CA1 region. In the DG, both 5 and 20 muM caffeine produced significantly greater PI uptake in ethanol-exposed female cultures compared to ethanol-naive female cultures and all male cultures. Similarly, 20 mu M caffeine caused markedly greater toxicity in female cultures as compared to male cultures in the CA1 region. Conclusions: Twenty-four-hour exposure to caffeine during EWD produced significant toxicity in the pyramidal cell layer of the CA3 region in male and female cultures, though toxicity in the granule cell layer of the DG and pyramidal cell layer of the CA1 region was observed only in female cultures. Greater sensitivity of the female slice cultures to toxicity upon caffeine exposure after prolonged ethanol exposure is consistent with previous studies of effects of a specific A1 receptor antagonism during EWD on toxicity and indicate that this effect is independent of the hormonal milieu. Together, these data suggest that the A1 receptor subtype is predominant in mediating caffeine's neurotoxic effects during EWD. These findings demonstrate the importance of considering gender/sex when examining neuroadaptive changes in response to ethanol exposure and withdrawal.

Source: Alcohol & Alcoholism.44, (6):567-574, 2009

National Birth Defects Prevention Study Maternal caffeine intake during pregnancy and orofacial clefts

Collier, S. A.; Browne, M. L.; Rasmussen, S. A.; Honein, M. A

Moderate caffeine intake during pregnancy is common, but little is known about its potential association with birth defects. METHODS: The National Birth Defects Prevention Study is a population-based, case-control study of major birth defects, excluding infants with single-gene disorders and chromosomal abnormalities. This analysis includes infants with cleft lip with or without cleft palate (CL/P) and cleft palate only (CPO), excluding infants whose cleft was secondary to holoprosencephaly or amniotic band sequence. Mothers reported dietary caffeine intake from coffee, tea, sodas, and chocolate in the year before pregnancy and reported intake of medications containing caffeine during pregnancy. We assessed the association between dietary caffeine intake, frequency of consuming each type of caffeinated beverage, medications containing caffeine, and CL/P or CPO among infants born from October 1997 through December 2004. RESULTS: This analysis included 1531 infants with CL/P, 813 infants with CPO, and 5711 infants with no major birth defects (controls). Examining dietary sources among control mothers, 11% reported consuming at least 300 mg of caffeine per day and 17% reported consuming less than 10 mg of caffeine per day; high consumption (>or=3 servings per day) was reported by 8% (coffee), 4% (tea), and 15% (sodas); medications containing at least 100 mg caffeine/dose were reported by less than 1%. Although some effect estimates were elevated for moderate caffeine intake from all beverages, estimates were closer to the null for high caffeine levels. Isolated CL/P was associated with use of medications containing at least 100 mg of caffeine per dose. CONCLUSIONS: Our data do not suggest an association between maternal dietary caffeine intake and orofacial clefts, but caffeine-containing medications merit further study.

Source: Birth Defects Research.85(10):842-9, 2009

Caffeine and anaerobic performance: ergogenic value and mechanisms of action.

Davis, J. K.; Green, J. M.

The effect caffeine elicits on endurance performance is well founded. However, comparatively less research has been conducted on the ergogenic potential of anaerobic performance. Some studies showing no effect of caffeine on performance used untrained subjects and designs often not conducive to observing an ergogenic effect. Recent studies incorporating trained subjects and paradigms specific to intermittent sports activity support the notion that caffeine is ergogenic to an extent with anaerobic exercise. Caffeine seems highly ergogenic for speed endurance exercise ranging in duration from 60 to 180 seconds. However, other traditional models examining power output (i.e. 30-second Wingate test) have shown minimal effect of caffeine on performance. Conversely, studies employing sport-specific methodologies (i.e. hockey, rugby, soccer) with shorter duration (i.e. 4-6 seconds) show caffeine to be ergogenic during high-intensity intermittent exercise. Recent studies show caffeine affects isometric maximal force and offers introductory evidence for enhanced muscle endurance for lower body musculature. However, isokinetic peak torque, one-repetition maximum and muscular endurance for upper body musculature are less clear. Since relatively few studies exist with resistance training, a definite conclusion cannot be reached on the extent caffeine affects performance. It was previously thought that caffeine mechanisms were associated with adrenaline (epinephrine)-induced enhanced free¬fatty acid oxidation and consequent glycogen sparing, which is the leading hypothesis for the ergogenic effect. It would seem unlikely that the proposed theory would result in improved anaerobic performance, since exercise is dominated by oxygen-independent metabolic pathways. Other mechanisms for caffeine have been suggested, such as enhanced calcium mobilization and phosphodiesterase inhibition. However, a normal physiological dose of caffeine in vivo does not indicate this mechanism plays a large role. Additionally, enhanced Na+/K+ pump activity has been proposed to potentially enhance excitation contraction coupling with caffeine. A more favourable hypothesis seems to be that caffeine stimulates the CNS. Caffeine acts antagonistically on adenosine receptors, thereby inhibiting the negative effects adenosine induces on neurotransmission, arousal and pain perception. The hypoalgesic effects of caffeine have resulted in dampened pain perception and blunted perceived exertion during exercise. This could potentially have favourable effects on negating decreased firing rates of motor units and possibly produce a more sustainable and forceful muscle contraction. The exact mechanisms behind caffeine's action remain to be elucidated.

Source: Sports Medicine.39(10):813-32, 2009

Caffeine, cycling performance, and exogenous CHO oxidation: a dose-response study

Desbrow, B.; Barrett, C. M.; Minahan, C. L.; Grant, G. D.; Leveritt, M. D

This study investigated the effects of a low and moderate caffeine dose on exogenous CHO oxidation and endurance-exercise performance. METHODS: Nine trained and familiarized male cyclists (mean +/-SD: 29.4 +/-4.5 yr, 81.3 +/-10.8 kg body weight [BW], 183.8 +/-8.2 cm, V O2peak = 61.7 +/- 4.8 mL.kg.min) undertook three trials, with training and high CHO diet being controlled. One hour before exercise, subjects ingested capsules containing placebo and 1.5 or 3 mg.kg BW of caffeine using a double-blind administration protocol. Trials consisted of 120 min steady-state cycling at approximately 70% V O2peak, immediately followed by a 7-kJ.kg BW time trial (TT). During exercise, subjects were provided with fluids containing C-glucose every 20 min to determine exogenous CHO oxidation. RESULTS: No significant TT performance improvements were observed during caffeine-containing trials (mean +/-SD: placebo = 30 min 25 s +/-3 min 10 s; 1.5 mg.kg BW = 30 min 42 s +/-3 min 41 s; and 3 mg.kg BW = 29 min 51 s +/-3 min 38 s). Furthermore, caffeine failed to significantly alter maximal exogenous CHO oxidation (maximal oxidation rates: placebo = 0.95 +/-0.2 g.min; 1.5 mg.kg BW = 0.92 +/-0.2 g.min; and 3 mg.kg BW = 0.96 +/-0.2 g.min). CONCLUSION: Low and moderate doses of caffeine have failed to improve endurance performance in fed, trained subjects.

Source: Medicine & Science in Sports & Exercise.41(9):1744-51, 2009

Caffeine inhibition of ionotropic glycine receptors

Duan, L.; Yang, J.; Slaughter, M. M.

We found that caffeine is a structural analogue of strychnine and a competitive antagonist at ionotropic glycine receptors (GlyRs). Docking simulations indicate that caffeine and strychnine may bind to similar sites at the GlyR. The R131A GlyR mutation, which reduces strychnine antagonism without suppressing activation by glycine, also reduces caffeine antagonism. GlyR subtypes have differing caffeine sensitivity. Tested against the EC(50) of each GlyR subtype, the order of caffeine potency (IC(50)) is: alpha2beta (248 +/-32 microm) alpha3beta (255 +/-16 microm) > alpha4beta (517 +/-50 microm) > alpha1beta(837 +/-132 microm). However, because the alpha3beta GlyR is more than 3-fold less sensitive to glycine than any of the other GlyR subtypes, this receptor is most effectively blocked by caffeine. The glycine dose response curves and the effects of caffeine indicate that amphibian retinal ganglion cells do not express a plethora of GlyR subtypes and are dominated by the alpha1beta GlyR. Comparing the effects of caffeine on glycinergic spontaneous and evoked IPSCs indicates that evoked release elevates the glycine concentration at some synapses whereas summation elicits evoked IPSCs at other synapses. Caffeine serves to identify the pharmacophore of strychnine and produces near-complete inhibition of glycine receptors at concentrations commonly employed to stimulate ryanodine receptors.

Source: Journal of Physiology.587(Pt 16):4063-75, 2009

Caffeine acutely activates 5\'adenosine monophosphate-activated protein kinase and increases insulin-independent glucose transport in rat skeletal muscles

Egawa, T.; Hamada, T.; Kameda, N.; Karaike, K.; Ma, X.; Masuda, S.; Iwanaka, N.; Hayashi, T.

Caffeine (1,3,7-trimethylxanthine) has been implicated in the regulation of glucose and lipid metabolism including actions such as insulin-independent glucose transport, glucose transporter 4 expression, and fatty acid utilization in skeletal muscle. These effects are similar to the exercise-induced and 5'adenosine monophosphate-activated protein kinase (AMPK)-mediated metabolic changes in skeletal muscle, suggesting that caffeine is involved in the regulation of muscle metabolism through AMPK activation. We explored whether caffeine acts on skeletal muscle to stimulate AMPK. Incubation of rat epitrochlearis and soleus muscles with Krebs buffer containing caffeine (> or =3 mmol/L, > or =15 minutes) increased the phosphorylation of AMPKalpha Thr(172), an essential step for full kinase activation, and acetyl-coenzyme A carboxylase Ser(79), a downstream target of AMPK, in dose-and time-dependent manners. Analysis of isoform-specific AMPK activity revealed that both AMPKalpha1 and alpha2 activities increased significantly. This enzyme activation was associated with a reduction in phosphocreatine content and an increased rate of 3-O-methyl-d-glucose transport activity in the absence of insulin. These results suggest that caffeine has similar actions to exercise by acutely stimulating skeletal muscle AMPK activity and insulin-independent glucose transport with a reduction of the intracellular energy status.

Source: Metabolism: Clinical & Experimental.58(11):1609-17, 2009

Caffeine enhances cognitive function and skill performance during simulated soccer activity

Foskett, A.; Ali, A.; Gant, N

There is little evidence regarding the benefits of caffeine ingestion on cognitive function and skillful actions during sporting performance, especially in sports that are multifaceted in their physiological, skill, and cognitive demands. PURPOSE: To examine the influence of caffeine on performance during simulated soccer activity. METHODS: Twelve male soccer players completed two 90-min soccer-specific intermittent running trials interspersed with tests of soccer skill (LSPT). The trials were separated by 7 days and adhered to a randomized crossover design. On each occasion participants ingested 6 mg/kg body mass (BM) of caffeine (CAF) or a placebo (PLA) in a double-blind fashion 60 min before exercise. Movement time, penalties accrued, and total time were recorded for the LSPT. Physiological and performance markers were measured throughout the protocol. Water (3 ml/kg BM) was ingested every 15 min. RESULTS: Participants accrued significantly less penalty time in the CAF trial (9.7 +/-6.6 s vs. PLA 11.6 +/-7.4 s; p = .02), leading to a significantly lower total time in this trial (CAF 51.6 +/-7.7 s vs. PLA 53.9 +/-8.5 s; p = .02). This decrease in penalty time was probably attributable to an increased passing accuracy in the CAF trial (p = .06). Jump height was 2.7% (+/-1.1%) higher in the CAF trial (57.1 +/-5.1 cm vs. PLA 55.6 +/-5.1 cm; p = .01). CONCLUSIONS: Caffeine ingestion before simulated soccer activity improved players' passing accuracy and jump performance without any detrimental effects on other performance parameters.

Source:  International Journal of Sport Nutrition & Exercise Metabolism.19(4):410-23, 2009

Coffee intake is associated with lower rates of liver disease progression in chronic hepatitis C

Freedman, N. D.; Everhart, J. E.; Lindsay, K. L.; Ghany, M. G.; Curto, T. M.; Shiffman, M. L.; Lee, W. M.; Lok, A. S.; Di Bisceglie, A. M.; Bonkovsky, H. L.; Hoefs, J. C.; Dienstag, J. L.; Morishima, C.; Abnet, C. C.; Sinha, R.; Halt, C.

Higher coffee consumption has been associated inversely with the incidence of chronic liver disease in population studies. We examined the relationship of coffee consumption with liver disease progression in individuals with advanced hepatitis C-related liver disease. Baseline coffee and tea intake were assessed in 766 participants of the Hepatitis C Antiviral Long-Term Treatment against Cirrhosis (HALT-C) trial who had hepatitis C-related bridging fibrosis or cirrhosis on liver biopsy and failed to achieve a sustained virological response to peginterferon plus ribavirin treatment. Participants were followed for 3.8 years for clinical outcomes and, for those without cirrhosis, a 2-point increase in Ishak fibrosis score on protocol biopsies. At baseline, higher coffee consumption was associated with less severe steatosis on biopsy, lower serum aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio, alpha-fetoprotein, insulin, and homeostatic model assessment (HOMA2) score, and higher albumin (P < 0.05 for all). Two hundred thirty patients had outcomes. Outcome rates declined with increasing coffee intake: 11.1/100 person-years for none, 12.1 for less than 1 cup/day, 8.2 for 1 to fewer than 3 cups/day, and 6.3 for 3 or more cups/day (P-trend = 0.0011). Relative risks (95% confidence intervals) were 1.11 (0.76-1.61) for less than 1 cup/day; 0.70 (0.48-1.02) for 1 to fewer than 3 cups/day; and 0.47 (0.27-0.85) for 3 or more cups/day (P-trend = 0.0003) versus not drinking. Risk estimates did not vary by treatment assignment or cirrhosis status at baseline. Tea intake was not associated with outcomes. CONCLUSION: In a large prospective study of participants with advanced hepatitis C-related liver disease, regular coffee consumption was associated with lower rates of disease progression.

Source: Hepatology.50(5):1360-9, 2009

Long-lasting resistance to haloperidol-induced catalepsy in male rats chronically treated with caffeine

Gongora-Alfaro, J. L.; Moo-Puc, R. E.; Villanueva-Toledo, J. R.; Alvarez-Cervera, F. J.; Bata-Garcia, J. L.; Heredia-Lopez, F. J.; Pineda, J. C

Chronic caffeine consumption has been inversely associated with the risk of developing Parkinson's disease. Here we assessed whether chronic caffeine treatment increases the resistance of male Wistar rats to haloperidol (1mg/kg, s.c.)-induced catalepsy, measured in the bar test at 15 min intervals during 3h. Caffeine (5mg/kg/day) was delivered for 6 months via drinking water. Control rats received only tap water. Treatments began when animals were 3-4 months old. In order to unveil long-lasting catalepsy refractoriness not attributable to the presence of caffeine in the brains of rats, they were evaluated from day 18 to day 27 after caffeine withdrawal, a time that is far in excess for the full excretion of a caffeine dose in this species. The average cataleptic immobility measured in caffeine-treated rats (n=23) was 1148+/-140 s, a value 34+/-8% lower than that recorded in control animals (n=20), whose mean immobility was 1736+/-137 s (P=0.0026, t-test). The percentage of catalepsy reduction measured in caffeine-treated rats evaluated on days 18-20 after caffeine discontinuation (-32+/-13%, n=12, P<0.05) was comparable to the catalepsy decrease recorded in those animals tested on days 21-27 (-36+/-10%, n=11, P<0.02), a finding compatible with the notion that the effect was indeed mediated by enduring changes of brain functioning and not by the physical presence of caffeine or its metabolites. Caffeine-treated rats also had higher catalepsy latency scores compared with control rats (P<0.01, U-test). The present findings show that chronic consumption of caffeine produces perdurable resistance to catalepsy induced by dopamine receptor blockade, possibly through enhancement of dopamine transmission, giving further support to the epidemiological results indicating that prolonged caffeine consumption affords neuroprotection against Parkinson's disease.

Source: Neurosciences Letters.463(3):210-4, 2009

Effect of moderate intakes of different tea catechins and caffeine on acute measures of energy metabolism under sedentary conditions

Gregersen, N. T.; Bitz, C.; Krog-Mikkelsen, I.; Hels, O.; Kovacs, E. M. R.; Rycroft, J. A.; Frandsen, E.; Mela,
D. J.; Astrup, A.

Green tea may stimulate energy metabolism; however, it is unclear if acute effects are caused by specific catechins, caffeine or their combination. This study examined the separate and combined effects of different catechins and caffeine on energy expenditure (EE) and fat oxidation over a single day. 15 healthy, normal-wt. males received capsules containing placebo, caffeine alone (150 mg) or caffeine plus a catechin mixture (600 mg) enriched in either epigallocatechin-3-gallate (EGCG), epigallocatechin or a mix of catechins, in a randomized cross-over double-blinded design. On each test day EE, respiratory quotient (RQ) and substrate oxidation were measured under sedentary conditions in a respiratory chamber for 13.5 h. No significant treatment effect was found on EE (P = 0.20) or RQ (P = 0.68). EGCG with caffeine insignificantly raised EE and fat oxidation vs. caffeine-only and placebo (EE 5.71 (s.e. 0.12) vs. 5.68 (s.e. 0.14) vs. 5.59 (s.e. 0.13) MJ/12.5 h, respectively; fat oxidation 84.8 (s.e. 5.2) vs. 80.7 (s.e. 4.7) vs. 76.8 (s.e. 4.0) g/12.5 h). Catechin/caffeine combinations at these dosages and mode of application had non-significant acute effects on EE and fat oxidation. The max. observed effect on EE of about 2% could still be meaningful for energy balance over much longer period of exposure. However, higher short-term effects reported in the literature may reflect variations in green tea extracts, added caffeine or synergies with physical activity. The specific mechanisms and conditions that may underpin observed longer-term benefits of catechin-enriched green tea consumption on body composition remain to be confirmed.

Source: British Journal of Nutrition.102, (8):1187-1194, 2009

Effects of ethanol and caffeine on behavior in C57BL/6 mice in the plus-maze discriminative avoidance task

Gulick, D.; Gould, T. J.

Caffeine is frequently consumed concurrent to or immediately following ethanol consumption. Identifying how caffeine and ethanol interact to modulate behavior is essential to understanding the co-use of these drugs. The plus-maze discriminative avoidance task (PMDAT) allows within-subject measurement of learning, anxiety, and locomotion. METHODS: For training, each mouse was placed in the center of the plus-maze for 5 min, and each time that the mouse entered the aversive enclosed arm, a light and white noise were turned on. At testing, each mouse was returned to the center of the maze for 3 min. No cues were turned on during testing. RESULTS: Ethanol (1.0-1.4 g/kg) dose¬dependently decreased anxiety and learning, and increased locomotion. Caffeine (5.0-40.0 mg/kg) dose¬dependently increased anxiety and decreased locomotion and learning. Caffeine failed to reverse ethanol¬induced learning deficits. However, 1.4 g/kg ethanol blocked the anxiogenic effect of caffeine. DISCUSSION: Although caffeine and ethanol interact to modulate behavior in the PMDAT, caffeine does not reverse ethanol-induced learning deficits. Ethanol-induced anxiolysis may contribute to alcohol consumption, while ethanol's blockade of caffeine-induced anxiogenesis may contribute to co-use.

Source: Behavioral Neuroscience.123(6):1271-8, 2009

Coffee drinking in middle age is not associated with cognitive performance in old age

Laitala, V. S.; Kaprio, J.; Koskenvuo, M.; Raiha, I.; Rinne, J. O.

It has been suggested that coffee has a protective effect on cognitive performance in old age, and this study analysed the potential association between coffee drinking in middle age and cognitive performance in old age in Finnish twins. Coffee consumption was high and associated with educational level and other baseline variables. The role of coffee in the pathogenesis of cognitive decline and dementia is discussed.

Source: American Journal of Clinical Nutrition, (September), 90 (3): 640-646, 2009

Effects of instant coffee consumption on oxidative DNA damage, DNA repair, and redox system in mouse liver

Morii, H.; Kuboyama, A.; Nakashima, T.; Kawai, K.; Kasai, H.; Tamae, K.; Hirano, T.

The effects of instant coffee consumption on cancer risk were examined in this study by analysing the oxidative DNA damage levels and the DNA repair and redox system in the livers of mice fed coffee. Levels of 8-hydroxydeoxyguanosine (8-OH-dG), a major form of oxidative DNA damage, expression of mouse 8-OH-dG repair-associated genes and redox system-associated genes, superoxide dismutase activity, and the lipid peroxidation level were analysed. The effect of coffee consumption on the risk of liver cancer as a result of oxidative stress is discussed.

Source: Journal of Food Science, (August), 74 (6): H155-H161, 2009

Effects of co-administration of tea epigallocatechin-3-gallate (EGCG) and caffeine on absorption and metabolism of EGCG in humans

Nakagawa, K.; Nakayama, K.; Nakamura, M.; Sookwong, P.; Tsuduki, T.; Niino, H.; Kimura, F.; Miyazawa,
T.

Based on the ratios of (-)-epigallocatechin-3-gallate (EGCG) and caffeine (CAF) levels found in commercial tea drinks, EGCG and CAF were co-administered to human volunteers at various EGCG/CAF ratios, and plasma EGCG was determined by high performance liquid chromatography with chemiluminescence detection. As for the results, in plasma taken after ingestion of a beverage containing 95 mg of EGCG alone, the area under the plasma EGCG concentration-time curve (AUC) was 857 ngxh/ml. A higher AUC (1,370 ngxh/ml) was observed when subjects ingested a beverage containing EGCG (95 mg) and a low amount of CAF (40 mg). In the case of ingestion of a beverage containing EGCG (95 mg) and a high amount of CAF (180 mg), the AUC tended to be somewhat higher (1,165 ngxh/ml), but not significantly so, compared with the beverage with EGCG alone. These findings (modulation of plasma EGCG level by CAF) provide ideas for modulating the bioavailability of tea catechins, which can be applied to tea-related drinks and foods.

Source: Bioscience, Biotechnology & Biochemistry.73(9):2014-7, 2009

Sex-specific differences on caffeine consumption and chronic stress-induced anxiety-like behavior and DNA breaks in the hippocampus

Noschang, C. G.; Pettenuzzo, L. F.; von Pozzer, Toigo E.; Andreazza, A. C.; Krolow, R.; Fachin, A.; Avila,
M. C.; Arcego, D.; Crema, L. M.; Diehl, L. A.; Goncalvez, C. A.; Vendite, D.; Dalmaz, C

Caffeine is widely consumed in beverages and food, and its consumption in high doses is associated with anxiety increase. Stress situations are often associated to coffee consumption, and have a strong influence on oxidative DNA damage. As there are sex-specific differences in many metabolic, neurochemical and behavioral aspects, the aim of this study is to verify the interaction between chronic consumption of caffeine and chronic stress on anxiety and DNA breaks in the hippocampus on male and female rats. Wistar rats were submitted to restraint stress for at least 50 days. The diet consisted of standard rat chow and caffeine 0.3 or 1 g/L in drinking water "ad libitum" as the only drinking source. Controls received tap water. Anxiety-like behavior and DNA breaks in the hippocampus were evaluated. Caffeine consumption and chronic stress increased anxiety-like behavior as well as DNA breaks in the hippocampus of male rats. No effect on these parameters was observed in females. These results may be related to the presence of estradiol, which may have anxiolytic and neuroprotective properties.

Source: Pharmacology, Biochemistry & Behavior.94(1):63-9, 2009

Caffeine -our favourite drug

Rogers, P. J.

This paper discusses the level of caffeine in tea, coffee and other caffeine-containing beverages, and its physiological and psychoactive effects on the human body. Aspects covered include: the effects of caffeine and caffeine withdrawal on cellular responses, alertness, mental performance, blood pressure and health; caffeine dependence and addiction; the popularity of caffeine-containing beverages; other components of tea and coffee (theanine, cafestol, chlorogenic acid and other phenols); and the effects of caffeine combined with painkillers (aspirin, paracetamol, ibuprofen and codeine) on pain and physical performance. The author concludes that insufficient research has been carried out to do a full risk assessment of the health effects of drinking tea, coffee and other caffeine-containing beverages.

Source: Biologist, 56 (3): 138-143, 2009

. Effects of caffeine and theophylline on coronary hyperemia induced by adenosine or dipyridamole.

Salcedo, J.; Kern, M. J.

The aims of this review are to examine the biochemical features of theophylline, caffeine, adenosine, and dipyridamole, their effects on coronary hyperemia, and to make recommendations on performing hyperemic lesion assessment after taking caffeine or theophylline. BACKGROUND: It is commonly thought that caffeine and theophylline interfere with adenosine and dipyridamole induced coronary hyperemia, thus frequently delaying scheduled assessments after inadvertent consumption. However, a limited amount of studies address the interactions of these substances thus leaving no clear consensus on when to delay coronary assessment after their intake. METHODS: For biochemical information on each substance, online and textbook references were utilized. For studies on the interactions of the substances with coronary hyperemia, broad search terms such as "caffeine AND adenosine" were applied in the major research data bases. RESULTS: A serum caffeine level of 3 to 4 mg/L at the time of an adenosine-hyperemia study does not affect the ability of perfusion stress imaging to detect coronary artery disease. The interactions of theophylline with adenosine-hyperemia are less clear while both caffeine and theophylline show significant interaction with dipyridamole-hyperemia. CONCLUSIONS: For dipyridamole-stress myocardial perfusion studies, caffeine products and theophylline medications should be discontinued for 24 hr. For adenosine-stress myocardial perfusion studies, theophylline medications should be discontinued for 12 hr; however, one cup of coffee may be taken up to 1 hr before the test without necessitating a delay or cancellation of the study. These same considerations hold true for patients undergoing cardiac catheterization and intravenous adenosine¬induced hyperemia.

Source: Catheterization & Cardiovascular Interventions.74(4):598-605, 2009

Does the presence of a pharmacological substance alter the placebo effect?--results of two experimental studies using the placebo-caffeine paradigm

Walach, H.; Schneider, R.

We employed the placebo-caffeine paradigm to test whether the presence or absence of a substance (caffeine) influences the placebo effect. Methods: In experiment 1 consisting of four conditions with n = 15 participants each (control, placebo, two double-blind groups, each with placebo only), we maximized the placebo effect through expectation. Effects were assessed with physiological (blood pressure, heart rate), psychomotor (response times), and well-being indicators (self-report). In experiment 2, caffeine was administered in one of the double-blind groups, and another condition was added where caffeine was given openly. RESULTS: Effect sizes were medium to large for some outcome parameters in experiment 1 and 2, showing partial replicability of the classical placebo effect. Although not formally significant, differences between the double blind placebo conditions of the two experiments (with and without caffeine present) were medium to small. There was a significant difference (p = 0.03) between experiment 1 and experiment 2 in the physiological variables, and a near significant interaction effect between groups and experiments in the physiological variables (p = 0.06). CONCLUSION: The question warrants further scrutiny. The presence of a pharmacological substance might change the magnitude of the placebo response.

Source: Human Psychopharmacology.24(7):549-58, 2009

Roasted coffees high in lipophilic antioxidants and chlorogenic acid lactones are more neuroprotective than green coffees

Yi-Fang, Chu; Brown, P. H.; Lyle, B. J.; Yumin, Chen; Black, R. M.; Williams, C. E.; Yi-Ching, Lin; Chih-Wei, Hsu; Cheng, I. H.

Oxidative stress is involved in many neurodegenerative processes leading to age-related cognitive decline. Coffee, a widely consumed beverage, is rich in many bioactive components, including polyphenols with antioxidant potential. In this study, regular and decaffeinated samples of both roasted and green coffee all showed high hydrophilic antioxidant activity in vitro, whereas lipophilic antioxidant activities were on average 30-fold higher in roasted than in green coffee samples. In primary neuronal cell culture, pretreatment with green and roasted coffees (regular and decaffeinated) protected against subsequent H2O2-induced oxidative stress and improved neuronal cell survival (green coffees increased neuron survival by 78%, compared to 203% by roasted coffees). All coffee extracts inhibited ERK1/2 activation, indicating a potential attenuating effect in stress-induced neuronal cell death. Interestingly, only roasted coffee extracts inhibited JNK activation, evidencing a distinctive neuroprotective benefit. Analysis of coffee phenolic compounds revealed that roasted coffees contained high levels of chlorogenic acid lactones (CGL); a significant correlation between CGL and neuroprotective efficacy was observed (R2 = 0.98). In conclusion, this study showed that roasted coffees are high in lipophilic antioxidants and CGL, can protect neuronal cells against oxidative stress, and may do so by modulation of the ERK1/2 and JNK signalling pathways.

Source: Journal of Agricultural & Food Chemistry.57, (20):9801-9808, 2009

Anti-obesity effects of epigallocatechin-3-gallate, orange peel extract, black tea extract, caffeine and their combinations in a mouse model

Wen, Huang; Yue, Liu; Dushenkov, S.; Chi-Tang, Ho; Mou-Tuan, Huang

The anti-obesity effects of epigallocatechin-3-gallate (EGCG), orange peel extract (OPE), black tea extract (BTE), and caffeine (CF) in female CF-1 mice were studied. Female CF-1 mice were fed high-fat diets containing 0.1% EGCG, 0.2% OPE, 0.2% BTE and 0.05% caffeine alone and in combination for 10 weeks. The body weight gain and weights of abdominal fat and brown adipose tissue were significantly reduced in mice whose diets contained OPE, BTE, caffeine, OPE+BTE and OPE+CF. Notably, mice fed a high-fat diet supplemented daily with 0.2% OPE+0.2% BTE+0.05% CF prevented body weight gain by 48.8%, parametrial fat pad weight by 88.2%, retroperitoneal fat pad weight by 82.8% and brown adipose tissue by 63.7% compared with mice fed a high-fat diet. On the basis of these findings, it was concluded that oral feeding of orange peel extract, black tea extract and caffeine had anti-obesity effects by suppressing body weight gain and adipose tissue formation.

Source: Journal of Functional Foods.1, (3):304-310, 2009

Polyphenolic chemistry of tea and coffee: a century of progress

Yu, Wang; Chi-Tang, Ho

Tea and coffee, the most popular beverages in the world, have been consumed for thousands of yr for their alluring flavours and health benefits. Polyphenols, particularly flavonoids and phenolic acids, are of great abundance in tea and coffee and contribute a lot to their flavour and health properties. This article discusses the polyphenol chemistry of tea and coffee, specifically their stability and the scavenging ability of reactive oxygen species (ROS) and reactive carbonyl species (RCS). For example, during the manufacturing and brewing process, green tea and black tea polyphenols undergo epimerization and oxidation, respectively. Meanwhile, lactonization and polymerization of chlorogenic acid are the major causes for degradation of polyphenols in coffee. Tea catechins, besides having antioxidant properties, have the novel characteristic of trapping reactive carbonyl species. The A ring of the catechins is the binding site for RCS trapping, whereas the B ring is the preferred site for antioxidation.

Source: Journal of Agricultural & Food Chemistry.57, (18):8109-8114, 2009

Caffeine reverses cognitive impairment and decreases brain amyloid-beta levels in aged Alzheimer\'s disease mice

Arendash, G. W.; Mori, T.; Cao, C.; Mamcarz, M.; Runfeldt, M.; Dickson, A.; Rezai-Zadeh, K.; Tane, J.; Citron, B. A.; Lin, X.; Echeverria, V.; Potter, H.

We have recently shown that Alzheimer's disease (AD) transgenic mice given a moderate level of caffeine intake (the human equivalent of 5 cups of coffee per day) are protected from development of otherwise certain cognitive impairment and have decreased hippocampal amyloid-beta (Abeta) levels due to suppression of both beta-secretase (BACE1) and presenilin 1 (PS1)/gamma-secretase expression. To determine if caffeine intake can have beneficial effects in "aged" APPsw mice already demonstrating cognitive impairment, we administered caffeine in the drinking water of 18-19 month old APPsw mice that were impaired in working memory. At 4-5 weeks into caffeine treatment, those impaired transgenic mice given caffeine (Tg/Caff) exhibited vastly superior working memory compared to the continuing impairment of control transgenic mice. In addition, Tg/Caff mice had substantially reduced Abeta deposition in hippocampus (decrease 40%) and entorhinal cortex (decrease 46%), as well as correlated decreases in brain soluble Abeta levels. Mechanistically, evidence is provided that caffeine suppression of BACE1 involves the cRaf-1/NFkappaB pathway. We also determined that caffeine concentrations within human physiological range effectively reduce active and total glycogen synthase kinase 3 levels in SweAPP N2a cells. Even with pre-existing and substantial Abeta burden, aged APPsw mice exhibited memory restoration and reversal of AD pathology, suggesting a treatment potential of caffeine in cases of established AD.

Source: Journal of Alzheimer's Disease.17(3):661-80, 2009

Caffeine suppresses amyloid-beta levels in plasma and brain of Alzheimer\'s disease transgenic mice

Cao, C.; Cirrito, J. R.; Lin, X.; Wang, L.; Verges, D. K.; Dickson, A.; Mamcarz, M.; Zhang, C.; Mori, T.; Arendash, G. W.; Holtzman, D. M.; Potter, H.

Recent epidemiologic studies suggest that caffeine may be protective against Alzheimer's disease (AD). Supportive of this premise, our previous studies have shown that moderate caffeine administration protects/restores cognitive function and suppresses brain amyloid-beta (Abeta) production in AD transgenic mice. In the present study, we report that acute caffeine administration to both young adult and aged AD transgenic mice rapidly reduces Abeta levels in both brain interstitial fluid and plasma without affecting Abeta elimination. Long-term oral caffeine treatment to aged AD mice provided not only sustained reductions in plasma Abeta, but also decreases in both soluble and deposited Abeta in hippocampus and cortex. Irrespective of caffeine treatment, plasma Abeta levels did not correlate with brain Abeta levels or with cognitive performance in individual aged AD mice. Although higher plasma caffeine levels were strongly associated with lower plasma Abeta1-40 levels in aged AD mice, plasma caffeine levels were also not linked to cognitive performance. Plasma caffeine and theophylline levels were tightly correlated, both being associated with reduced inflammatory cytokine levels in hippocampus. Our conclusion is two-fold: first, that both plasma and brain Abeta levels are reduced by acute or chronic caffeine administration in several AD transgenic lines and ages, indicating a therapeutic value of caffeine against AD; and second, that plasma Abeta levels are not an accurate index of brain Abeta levels/deposition or cognitive performance in aged AD mice.

Source: Journal of Alzheimer's Disease.17(3):681-97, 2009

Structural features of partially acetylated coffee galactomannans presenting immunostimulatory activity

Simoes, J.; Nunes, F. M.; Domingues, M. de; Coimbra, M. A.

The galactomannans purified from coffee infusions have been shown to present in vitro immunostimulatory activity on murine B-and T-lymphocytes. These properties have also been shown characteristic of the galactomannans recovered from coffee residue by strong alkali solutions and rendered soluble in water by partial acetylation. In this study, purified fractions of galactomannans with immunostimulatory activity obtained from coffee infusion and from coffee residue were compared according to their average molecular weight determined by size-exclusion chromatography on Sephacryl S300, glycosidic-linkage composition by methylation analysis, selective hydrolysis by an endo-(1 rightwards-arrow 4)-beta-D-mannanase, analysis of the resultant oligosaccharide profile by Bio-Gel P2 separation, and determination of the pattern of acetylation by electrospray tandem mass spectrometry (ESI-MS/MS). It was found that the galactomannans have a comparable molecular weight (90-110 kDa), and similar glycosidic-linkage composition. However, the galactomannans from coffee residue were preferentially acetylated in the side chain residues whereas the galactomannans recovered from coffee infusions only had acetyl groups directly linked to the backbone residues. These results show that these polysaccharides that present comparable immunostimulatory properties have different acetylation patterns.

Source: Carbohydrate Polymers.79, (2):397-402, 2010

Kinetic analysis and mechanism on the inhibition of chlorogenic acid and its components against porcine pancreas alpha-amylase isozymes I and II

Narita, Y.; Inouye, K

Chlorogenic acid (5-caffeoylquinic acid, 5-CQA) is a polyphenol present in large amounts in green coffee beans. The inhibitory effects of 5-CQA and its components, caffeic acid (CA) and quinic acid (QA), on the 2 porcine pancreas alpha-amylase (PPA) isozymes, PPA-I and PPA-II, were investigated using p-nitrophenyl-alpha-D-maltoside as substrate at pH 6.9 and 30 degrees C. The inhibition potencies of the respective inhibitors against both PPA isozymes were almost the same and in the order of 5-CQA > CA >> QA. Their IC50 values were 0.07-0.08, 0.37-0.40 and 25.3-26.5mM, respectively. The inhibition mechanisms of 5-CQA and CA were investigated by kinetic analyses, and the inhibitor constants Ki and Ki' (for the free enzyme and enzyme-substrate complex, respectively) were determined. 5-CQA and CA showed mixed-type inhibition with Ki > Ki' against both PPA-I and PPA-II. The binding of PPA-I or PPA-II with 5-CQA or CA was all exothermic and enthalpy-driven. QA is a poor inhibitor, and its inhibitory mode was unique and hardly analysed by a simple Michaelis-Menten-type interaction between the enzyme and inhibitor. However, it was shown that the inhibitory activity of CA was enhanced 5x by ester-bond formation with QA in the form of 5-CQA. It is suggested that these results could be used in the development of alpha-amylase inhibitors for the prevention of diabetes and obesity.

Source: Journal of Agricultural & Food Chemistry.57, (19):9218-9225, 2009