AGRONOMY

Quality assessment of organic coffee beans for the preparation of a candidate reference material

Tagliaferro, F. S.; Nadai-Fernandes, E.-A. de; Bacchi, M. A.

A random sampling was carried out in the coffee beans collected for the preparation of the organic green coffee reference material in view of assessing the homogeneity and the presence of soil as impurity. Fifteen samples were taken for the between-sample homogeneity evaluation. One of the samples was selected and 10 test portions withdrawn for the within-sample homogeneity evaluation. Br, Ca, Co, Cs, Fe, K, Na, Rb, Sc and Zn were determined by instrumental neutron activation analysis (INAA). The F-test demonstrated that the material is homogeneous for Ca, Co, Cs, K and Sc, but not homogeneous for Br, Fe, Na, Rb and Zn. Results of terrigenous elements suggested negligible soil contamination in the raw material.

Source : J Radioanal Nucl Chem 2006 vol. 269 (2), pp 371 - 375

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

Ramiro, D. A.; Guerreiro-Filho, O.; Mazzafera, P.

We examined the role of phenolic compounds, and the enzymes peroxidase and polyphenol oxidase, in the expression of resistance of coffee plants to Leucoptera coffeella (Lepidoptera: Lyonetiidae). The concentrations of total soluble phenols and chlorogenic acid (5-caffeoylquinic acid), and the activities of 35 the oxidative enzymes peroxidase (POD) and polyphenol oxidase (PPO), were estimated in leaves of Coffea arabica, C. racemosa, and progenies of crosses between these species, which have different levels of resistance, before and after attack by this insect. The results indicate that phenols do not play a central role in resistance to the coffee leaf miner. Differences were detected between the parental species in terms of total soluble phenol concentrations and activities of the oxidative enzymes. However, resistant and susceptible hybrid plants did not differ in any of these characteristics. Significant induction of chlorogenic acid and PPO was only found in C. racemosa, the parental donator of the resistance genes against L. coffeella. High-performance liquid chromatography (HPLC) analysis also showed qualitative similarity between hybrids and the susceptible C. arabica. These results suggest that the phenolic content and activities of POD and PPO in response to the attack by the leaf miner may not be a strong evidence of their participation in direct defensive mechanisms.

Source : J Chem Ecol 2006 vol. 32 (9), pp 1977 - 1988

An Effective and Low-Cost Culture Medium for Isolation and Growth of Xylella fastidiosa from Citrus and Coffee Plants

Lopes, S. A.; Torres, S. C.

Buffered charcoal-yeast extract medium (BCYE) has been used for isolation of Xylella fastidiosa from citrus (Citrus sinensis) and coffee (Coffea arabica) plants affected by citrus variegated chlorosis (CVC) and coffee leaf scorch (CLS). BCYE is composed of ACES (2-[2-amino-2oxoethyl) amino]-ethanesulfonic acid) buffer, activated charcoal, yeast extract, L-cysteine, ferric pyrophosphate, and agar. ACES buffer is costly and not always commercially available in Brazil, and the L-cysteine and ferric pyrophosphate need to be filter sterilized in 0.22-mum pore membranes before inclusion in the medium. Omission of Lcysteine, addition of magnesium sulfate, and replacements of ACES and ferric pyrophosphate for potassium phosphate and ferrous sulfate resulted in an effective, less expensive, and entirely autoclavable medium, named phosphate buffered charcoal-yeast extract medium (PCYE). The final cost of PCYE was approximately one tenth that of BCYE. Its effectiveness was tested for the isolation of X. fastidiosa from symptomatic leaves collected from 52 citrus plants affected by CVC and 43 coffee plants affected by CLS. PCYE was as effective as BCYE and has been used routinely in our and other laboratories for isolation, growth, and quantification of X. fastidiosa from plant tissues.

Source : Curr Microbiol 2006 vol .53 (6), pp 467 - 469

Diversidade de fungos filamentosos associados a Hypothenemus hampei (Ferrari) (Coleoptera: Scolytidae) e suas galerias em frutos de Coffea canephora (Pierre). [Diversity of filamentous fungi associated with Hypothenemus hampei (Ferrari) (Coleoptera: Scolytidae) and its galleries in berries of Coffea canephora (Pierre)]

Gama, Fde C.; Teixeira, C. A.; Garcia, A.; Costa, J. N.; Lima, D. K.

Field sampling was carried out in Ouro Preto d'Oeste - Rondonia (10 degrees 45'S and 62 degrees 15'W) to evaluate the mycobiota associated with Hypothenemus hampei Ferrari [cuticle, mouth, prothorax (mycangia), gut and feces] and its galleries on berries of Coffea canephora Pierre. Ten genera (201 isolates) were directly related with the insect while five genera (20 isolates) were related with galleries on berries. All the genera identified in the insects were also present in their galleries, what indicates that boring may be an active way of fungi inoculation by H. hampei. The fungi genera were more diverse in the mouth and prothorax of borers, and lower in feces. Fusarium, Penicillium and Geotrichum, with abundance of 55.7, 24.3 and 10.8%, respectively, were dominant genera. In the galleries Fusarium, Geotrichum, Trichoderma and Aspergillus with abundance of 33.3, 29.6, 18.5 and 14.8%, respectively, were dominant genera. The overall presence of Fusarium in coffee berry borer and its galleries) reinforces previous indications of a close interaction between H. hampei-Fusarium. The presence of Aspergillus and Penicillium emphasizes the possibility of "ochratoxin dispersion" by the borer. This work provides the first record of the mycobiota associated with H. hampei in C. canephora. Among the identified genera, Cephalosporium, Geotrichum and Oidiodendrum were recorded for the first time in association with H. hampei and its galleries in C. canephora.

Source : Neotrop Entomol 2006 vol .35 (5), pp 573 - 578

BIOCHEMISTRY / BIOTECHNOLOGY

Developments in coffee biotechnology - in vitro plant propagation and crop improvement

Kumar, V.; Naidu, M. M.; Ravishankar, G. A

Coffee is an important plantation crop grown in about 80 countries across the globe. In recent years, coffee attained lot of attention in the biotechnology research area. Since last three decades, there has been a steady flow of information on coffee biotechnology and now it is entering into the genomic era. Major milestones in coffee biotech research are successful in vitro manipulation and multiplication of coffee, development of gene transfer protocols and generation of transgenic coffee plants with specific traits. The isolation of genes involved in caffeine biosynthetic pathway has opened up new avenues for generating caffeine free transgenic coffee. With the initiation of international coffee genomics initiatives, the genomic research in coffee is expected to reach new dimensions. The IPR issues may play crucial role in sharing of benefits during international collaborations in near future. This review focuses on the basic and applied aspects of coffee biotechnology for newer potentials.

Source : Plant Cell 2006 vol. 87 (1), pp 49 - 65

Aluminium-induced phospholipid signal transduction pathway in Coffea arabica suspension cells and its amelioration by silicic acid

Quintal-Tun, F.; Munoz-Sanchez, J. A.; Ramos-Diaz, A.; Escamilla-Bencomo, A.; Martinez-Estevez, M.; Exley, C.; Hernandez-Sotomayor, S. M.

Coffee (Coffea arabica L.) is of economic importance worldwide. Its growth in organic-rich acidic soils is influenced by aluminium such that coffee yield may be impaired. Herein we have used the Al-sensitive C. arabica suspension cell line L2 to analyse the effect of two different Al species on the phosphoinositide signal transduction pathway. Our results have shown that the association of Al with coffee cells was affected by the pH and the form of Al in media. More Al was associated with cells at pH 4.3 than 5.8, whereas when Al was present as hydroxyaluminosilicates (HAS) the association was halved at pH 4.3 and unchanged at pH 5.8. Two signal transduction elements were also evaluated; phospholipase C (PLC) activity and phosphatidic acid (PA) formation. PLC was inhibited (approximately 50%) when cells were incubated for 2h in the presence of either AlCl(3) or Al in the form of HAS. PA formation was tested as a short-term response to Al. By way of contrast to what was found for PLC, incubation of cells for 15min in the presence of AlCl(3) decreased the formation of PA whereas the same concentration of Al as HAS produced no effect upon its formation. These results suggest that Al is capable to exert its effects upon signal transduction as Al((aq))(3+) acting upon a mechanism linked to the phosphoinositide signal transduction pathway.

Source : J Inorg Biochem 2007 vol. 101 (2), pp 362 - 369

A simple method to measure effective catalase activities: Optimization, validation, and application in green coffee

Montavon, P.; Kukic, K. R.; Bortlik, K.

Oxidative metabolism in coffee cherries during maturation appears to be regulated by the timely expression of redox enzymes such as catalase (CAT), peroxidase (POD), and polyphenoloxidase (PPO). Among these enzymes, CAT is suspected to contribute significantly in setting the redox status of the healthy cherry and the processed bean. The initial redox status of the green bean might further control the nature and dynamics of reactions induced by roasting and eventually quality aspects of the end product. In this respect, Arabica (Coffea arabica) and Robusta (Coffea canephora) typically differ by their cup coffee flavor profiles. We developed an assay that allowed us to screen numerous green coffee samples for effective CAT activities. The proposed assay, which monitors CAT activities by online oxygen sensing in green coffee crude suspensions incubated with H(2)O(2), seeks to integrate potential effects of endogenous inhibitors and activators. After optimization and validation of the assay, 23 Arabicas, 23 Robustas, and 8 Arabustas were analyzed. Nearly all Arabicas (22 of 23) harbored high CAT activity levels, whereas all Robustas harbored low ones. Arabustas performed like Arabicas of the lower CAT activity range. The traditional spectrophotometric assay did not reveal these specificities. Because of its simplicity, our assay might be valuable for assessing effective CAT activities in various plant tissues.

Source : Anal Biochem 2007 vol. 360 (2), pp 207 - 215

Identification, characterization and utilization of EST-derived genic microsatellite markers for genome analyses of coffee and related species

Aggarwal, R. K.; Hendre, P. S.; Varshney, R. K.; Bhat, P. R.; Krishnakumar, V.; Singh, L.

Genic microsatellites or EST-SSRs derived from expressed sequence tags (ESTs) are desired because these are inexpensive to develop, represent transcribed genes, and often a putative function can be assigned to them. In this study we investigated 2,553 coffee ESTs (461 from the public domain and 2,092 in-house generated ESTs) for identification and development of genic microsatellite markers. Of these, 2,458 ESTs (all >100 bp in size) were searched for SSRs using MISA-search module followed by stackPACK clustering that revealed a total of 425 microsatellites in 331 (13.5%) non-redundant ESTs/consensus sequences suggesting an approximate frequency of 1 SSR/2.16 kb of the analysed coffee transcriptome. Identified microsatellites mainly comprised of di-/tri-nucleotide repeats, of which repeat motifs AG and AAG were the most abundant. A total of 224 primer pairs could be designed from the non-redundant SSR-positive ESTs (excluding those with only mononucleotide repeats) for possible use as potential genic markers. Of this set, a total of 24 (10%) primer pairs were tested and 18 could be validated as usable markers. Sixteen of these markers revealed moderate to high polymorphism information content (PIC) across 23 genotypes of C. arabica and C. canephora, while 2 markers were found to be monomorphic. All the markers also showed robust cross-species amplifications across 14 Coffea and 4 Psilanthus species. The apparent broad cross-species/genera transferability was further confirmed by cloning and sequencing of the amplified alleles. Thus, the study provides an insight about the frequency and distribution of SSRs in coffee transcriptome, and also demonstrates the successful development of genic-SSRs. It is expected that the potential markers described here would add to the repertoire of DNA markers needed for genetic studies in cultivated coffee and also related taxa that constitute the important secondary genepool for coffee improvement.

Source : Theor Appl Genet 2007 vol. 114 (2), pp 359 - 372

PROCESSING

[Adsorption isotherms of soluble spray-dried coffee.]

Ocampo, M. JA; Giraldo, G.-G. I.

Adsorption isotherms for spray-dried soluble coffee were determined by a gravimetric method at 25, 30 and 35°C with aw ranging from 0.1 to 0.90 and fitted to the Guggenheim-Anderson-de-Boer (GAB) equation. Isosteric heat of sorption was also determined at moisture content of 0.01-25%. Results showed that the GAB model was able to predict adsorption characteristics of coffee with good precision (relative deviation of <5%). Increasing temp. resulted in an increase in coffee aw at constant humidity, with greatest rises noted at aw >0.4. Isosteric heat of sorption decreased with increasing moisture content. [Literature references for this article are available via the internet at www.alcion/Alimentacion, Equipos y Tecnologia/Indice de articulos publicados.]

Source : Alimentacion Equipos y Tecnologia 2006 vol. 25 (214),  pp 46 - 49

Coffee with a conscience

Ashman, H.; Beckley, J.

This article discusses US markets for ethically produced and branded coffee products

Source : Food Processing 2006 vol. 67 (8), pp 31 - 32

CHEMISTRY / SENSORICS

Investigation of sample treatment steps for the analysis of polycyclic aromatic hydrocarbons in ground coffee

Houessou, J.K.; delteil, C.; Camel, V.

Polycyclic aromatic hydrocarbons (PAHs) are pollutants that can contaminate food either via the environment or with their formation in food processing caused by elevated temperatures. This study investigated different sample treatment methods for the determination of PAHs in ground coffee. Pressurised liquid extraction (PLE) was combined with different clean-up methods; PLE with hexane/acetone under 150 C, followed by alkaline saponification, cyclohexane extraction and silica solidphase extraction gave best results. PAHs were determined in ground coffee, and were identified using HPLC-diode array detection and GC-MS.

Source : J Agric Food Chem 2006 vol. 54 (20), pp 7413-7421

Linear and non-linear kinetics in the synthesis and degradation of acrylamide in foods and model systems

Corradini, M. G.; Peleg, M.

An approach for modelling the kinetics of acrylamide synthesis and degradation, which does not require any of the traditional assumptions, is presented, and its potential application under isothermal and non-isothermal conditions is considered. Aspects covered include: isothermal formation and degradation of acrylamide; isothermal acrylamide formation in foods (wheat and rye doughs, potato flakes, coffee, potato chips and wheat flour); acrylamide formation in model systems (the glucose-asparagine reaction, effect of amino acid presence, comparison of 3 different models, effect of added amino acids as viewed through a combination of 2 different models); and non-isothermal formation and degradation of acrylamide (non-isothermal synthesis of acrylamide between 100 and 160°C, non-isothermal formation of acrylamide at varying temp. between 100 and 200°C, simulated non-isothermal formation in heated doughs).

Source : Critic Rev Food Sci Nutr 2006 vol .46 (6), pp 489 – 517

Antibacterial activity of coffee extracts and selected coffee chemical compounds against enterobacteria

Almeida, A.-A. P.; Farah, A.; Silva, D.-A. M.; Nunan, E. A.; Gloria, M.-B. A.

In vitro antimicrobial activity of commercial coffee extracts and chemical compounds was investigated against 9 strains of enterobacteria. Antimicrobial activity, measured by the disc diffusion method, was observed in both the extracts and tested chemical compounds. Even though pH, colour and the contents of trigonelline, caffeine and chlorogenic acids differed significantly among the coffee extracts, no significant differences were observed in their antimicrobial activity. Caffeic acid and trigonelline showed similar inhibitory effects against growth of the microorganisms. Caffeine, chlorogenic acid and protocatechuic acid showed particularly strong effects against Serratia marcescens and Enterobacter cloacae. The IC50 and IC90 values for the compounds determined by the microtiter plate method indicated that trigonelline, caffeine and protocatechuic acids are potential natural antimicrobial agents against Salmonella enterica. The concn. of caffeine found in coffee extracts was sufficient to account for 50% of the antimicrobial activity against S. enterica, which is relevant to human safety.

Source : J Agric Food Chem 2006 vol. 54 (23), pp 8738 - 8743

Development and validation of a food frequency questionnaire for the assessment of dietary total antioxidant capacity

Pellegrini, N.; Salvatore, S.; Valtuena, S.; Bedogni, G.; Porrini, M.; Pala, V.; Rio, D. del; Sieri, S.; Miglio, C.; Krogh, V.; Zavaroni, I.; Brighenti, F.

Knowledge of the total antioxidant capacity (TAC) of the diet may be an important tool to monitor the protective effect of plant foods in epidemiological studies. Therefore, a semi-quantitative food frequency questionnaire (FFQ) was developed for the assessment of dietary TAC by 3 different assays, i.e., Trolox equivalent antioxidant capacity (TEAC), total radical-trapping antioxidant parameter (TRAP) and ferric reducing-antioxidant power (FRAP). The FFQ consists of 53 questions concerning the major sources of dietary TAC in Northern Italy and was validated against a 3-day weighed food record (3D-WR) in 285 individuals (159 males and 126 females) aged 35-88 yr and living in the province of Parma (Italy). Plasma TAC was also evaluated in a subgroup of subjects using the TEAC and FRAP assays. The FFQ was associated with 3D-WR (quadratic-weighted kappa= 0.49 for TEAC, 0.53 for TRAP and 0.49 for FRAP; P < 0.0001) and proved reasonably accurate to classify individuals into quartiles of TAC intake. The FFQ had a good repeatability when readministered after 1 yr in 55 subjects (quadratic-weighted kappa for intertertile agreement = 0.66 for TEAC, 0.70 for TRAP and 0.68 for FRAP; P < 0.0001). With both dietary instruments, the main contributors to TAC intake were coffee and tea in women, and alcoholic beverages in men, followed by fruits and vegetables in both sexes. Plasma TAC and dietary TAC were not associated. It is concluded that this FFQ has the potential for being used to rank subjects on the basis of their antioxidant intake as determined by dietary TAC in large epidemiological studies. It is suggested that the FFQ should be validated in external populations before being used for research purposes.

Source : J Nutrition 2007 vol. 137 (1), pp 93 - 98

A comparison of SnifProbe and SPME for aroma sampling

Poliak, M.; Kochman, M.; Gordin, A.; Amirav, A.

Solid phase microextraction (SPME) was compared with the SnifProbe for coffee aroma sampling. The main difference between SPME and SnifProbe is in the relative motion of the sampled air. While SPME is based on static air sampling and the achievement of equilibrium, SnifProbe is based on active air pumping through the adsorption trap. A second difference concerns the sample introduction into the GC injector for its intra injector thermal desorption. SPME is based on the use of a special syringe for sample introduction without any change to the injector, while SnifProbe requires a ChromatoProbe for sample introduction. It was found that as a result of these differences, while SnifProbe provides a more faithful (representative) headspace and aroma sample collection, SPME is characterized by major compound dependent sample bias. In addition, SnifProbe enabled much faster sample collection than SPME. Since SnifProbe uses the ChromatoProbe for sample introduction into the GC, bigger sample collection/trapping devices such as silicone tubing can be used, and as a result, over 10x superior SnifProbe sensitivity (vs. SPME) was demonstrated. Additional SnifProbe and SPME features are compared and discussed.

Source : Chromatographia 2006 vol. 64 (7-8), pp 487 - 493

Single-laboratory validation of a method for the determination of furan in foods by using static headspace sampling and gas chromatography/mass spectrometry

Nyman, P. J.; Morehouse, K. M.; McNeal, T. P.; Perfetti, G. A.; Diachenko, G. W.

The widespread presence of furan in foods, including cooked and canned meats, roasted coffee, beer and wheat breads, has become a food safety issue since the discovery that it may be a carcinogen. This paper describes the development and validation of a headspace gas chromatography/mass spectrometry (GC-MS) method for the determination of furan. The method was shown to have detection and quantification limits from 0.2-0.6 ng/g in apple juice to 0.9-2.9 ng/g in peanut butter, with recoveries of 89.4-108%. The method was used to analyse over 300 food samples, which had furan levels up to 122 ng/g (found in baked beans).

Source : J AOAC Intern 2006 vol. 89 (5), pp 1417-1424

Synthesis and structure determination of covalent conjugates formed from the sulfury-roasty-smelling 2-furfurylthiol and di- or trihydroxybenzenes and their identification in coffee brew

Muller, C.; Hemmersbach, S.; Slot, G. V.; Hofmann, T.

Recent investigations demonstrated that the reaction of odor-active thiols such as 2-furfurylthiol with thermally generated chlorogenic acid degradation products is responsible for the rapid aroma staling of coffee beverages. To get a clear understanding of the molecular mechanisms underlying this aroma staling, the existence of putative phenol/thiol conjugates needs to be verified in coffee. The aim of the present study was therefore to synthesize such conjugates for use as reference substances for LC-MS screening of coffee. To achieve this, catechol, 3-methyl-, 4-methyl-, and 4-ethylcatechol, pyrogallol, hydroxyhydroquinone, 5-O-caffeoylquinic acid, and caffeic acid, respectively, were reacted with 2- furfurylthiol in the presence of iron(III) chloride and air oxygen. After purification, the structures of 25 phenol/thiol conjugates were identified by means of LC-MS/MS and 1D/2D NMR experiments. Using these compounds as reference materials, four conjugates, namely, 3-((2-furylmethyl)sulfanyl)catechol, 3-((2-furylmethyl)sulfanyl)-5-ethylcatechol, 4-((2-furylmethyl)sulfanyl)hydroxyhydroquinone, and 3,4-bis((2-furylmethyl)sulfanyl) hydroxyhydroquinone, were identified for the first time in coffee brew by means of HPLC-MS/MS(MRM). These findings clearly demonstrate catechol, 4-ethylcatechol, and hydroxyhydroquinone as the primary thiol trapping agents involved in the aroma staling of coffee beverages. Keywords: Coffee; aroma staling; 2-furfurylthiol; chlorogenic acid; caffeic acid; catechol; hydroxyhydroquinone; quinone; phenol oxidation.

Source : J Agric Food Chem 2006 vol. 54 (26), pp 10076 - 10085

Quantitative Precursor Studies on Di- and Trihydroxybenzene Formation during Coffee Roasting Using "In Bean" Model Experiments and Stable Isotope Dilution Analysis

Muller, C.; Lang, R.; Hofmann, T.

The objective of this study was to investigate the potential of various raw bean components as precursors of pyrogallol (1), hydroxyhydroquinone (2), catechol (3), 4-ethylcatechol (4), 4-methylcatechol (5), and 3- methylcatechol (6) under quasi "natural" roasting conditions by using the recently developed "in bean" model roast experiments. Freeze-dried, fully extracted bean shells were loaded with aqueous solutions of either single coffee compounds or fractions isolated from the raw bean solubles. After freeze-drying, these reconstituted beans were roasted, aqueous coffee brews were prepared, and the target phenols were quantified by means of a stable isotope dilution assay with LC-MS/MS detection. On the basis of the quantitative data, it can be concluded that upon coffee bean roasting, catechol (3) is primarily formed by degradation of caffeoylquinic acids from both the caffeic acid and the quinic acid moiety of the molecule, as well as from Maillard-type reactions from carbohydrates and amino acids. In contrast, pyrogallol (1) and hydroxyhydroquinone (2) are efficiently generated from carbohydrates and amino acids and, in addition, from free or chlorogenic acid bound quinic acid moieties. 4-Ethylcatechol (4) is exclusively generated upon thermal breakdown of caffeic acid moieties. 3-Methylcatechol (6) is formed primarily from the Maillard reactions and, to a minor extent, also from various phenolic precursors, whereas 4- methylcatechol (5) is produced in trace amounts only from all of the different precursors investigated. On the basis of this precursor study, reaction routes explaining the formation of the target phenols are proposed. Keywords: Coffee; chlorogenic acids; caffeic acid; quinic acid; pyrogallol; hydroxyhydroquinone; catechol; 4-ethylcatechol; 4-methylcatechol; 3-methylcatechol; stable isotope dilution analysis.

Source : J Agric Food Chem vol. 54 (26), pp 10086 - 10091

Supercritical fluid extraction (SFE) of 4(5)-methylimidazole (4-MeI) and 2-acetyl-4(5)-(1,2,3,4)- tetrahydroxybutyl-imidazole (THI) from ground-coffee with high-performance liquid chromatographic electrospray mass spectrometric quantification (HPLC/ESI-MS)

Lojkova, L.; Klejdus, B.; Moravcova, J.; Kuban, V.

During coffee roasting, undesirable imidazole compounds are formed by heating saccharides with nitrogenous compounds. This study examined the supercritical fluid extraction of 2-acetyl-4(5)-(1,2,3,4)- tetrahydroxybutyl-imidazole (THI) and 4(5)-methylimidazole (4-MeI) from powdered solid coffee matrix. Method efficiency was compared with that of solid-phase extraction using SCX Disc cartridges. Analytes were determined using isocratic liquid chromatography-MS. Samples of Arabica coffee from different locations and off-the-shelf coffee products were analysed. Advantages of the new method for the determination of THI and 4-MeI from coffee samples are discussed.

Source : Food Add Contam 2006 vol. 23 (10), pp 963-973

Flavor chemistry of tea and coffee drinks

Kumazawa, K.

Bottled or canned tea and coffee drinks are the most important commercial soft drinks in Japan, and research is ongoing into how to provide and maintain a fresh flavour. This paper reviews research into the potent odorants in Japanese green tea infusions and roasted coffee brews and discusses the deterioration of tea and coffee flavours during manufacturing. Topics discussed include: aroma extraction dilution analysis: a powerful tool for research on potent odorants in tea and coffee flavours; potent odorants in tea infusions and coffee brews; and flavour changes in tea and coffee drinks during manufacturing process.

Source : Food Sci Technol Res 2006 vol. 12 (2), pp 71-84  (not available on-line)

COFFEE & HEALTH

Coffee and cirrhosis: active ingredients?

Vinson, J. A.

In an epidemiology study,  a dose-response inverse association has been  convincingly demonstrated between coffee drinking and alcoholic cirrhosis and to a lesser extent between coffee drinking and nonalcoholic cirrhosis. In a cross-sectional study, coffee consumption was also significantly related to a lower prevalence of transaminase enzymes (markers of liver damage), with a stronger association for those who drank large quantities of alcohol. Tea drinking was not related to cirrhosis, but the numbers of heavy tea drinkers were small in this population. The authors speculate that the active principle may be caffeine. We strongly support the hypothesis that it is the polyphenol antioxidant compounds in coffee that are the causative agents and that they may act in concert with caffeine, which is also hepatoprotective.

Source : Arch Intern Med 2006 vol. 166 (21), pp 2404 - 2405

Is caffeine addictive?- A review of the literature

Satel, S.

The common-sense use of the term addiction is that regular consumption is irresistible and that it creates problems. Caffeine use does not fit this profile. Its intake does no harm to the individual or to society and its users are not compelled to consume it. Though cessation of regular use may result in symptoms such as headache and lethargy, these are easily and reliably reversed by ingestion of caffeine. Some have argued that continued caffeine use is an attempt to suppress low grade withdrawal symptoms such as sleepiness and lethargy. In some moderate users, this is possible; however, in experimental contexts, the phenomenon is too inconsistent to constitute a reliably valid syndrome.

Source : Am J Drug Alcohol Abuse 2006 vol. 32 (4), pp 493 - 502

Coffee - the truth about the bean

Musgrove, C.

Potential positive and negative effects of coffee consumption on health are discussed in an attempt to determine whether there is any cause for concern about drinking coffee. Aspects considered include: coffee and cancer (lack of effect on cancer of the mouth, pharynx, oesophagus, stomach or sex organs, evidence for protective effects against colorectal cancer and possible increased risk for bladder cancer); coffee, hypertension and cardiovascular disease risk (effects on homocysteine levels, effect of boiled coffee vs. other types of coffee); coffee, caffeine and bone health (effect on Ca absorption and risk for osteoporosis); and coffee, caffeine and reproductive effects (risk for low birth wt. and miscarriage, and effects of caffeine in human milk on breast-fed infants). Overall, evidence indicates that regular, moderate coffee consumption (up to 5 cups/day in the general non-pregnant population) does not pose a risk to health.

Source : Nutrition Bulletin 2006 vol. 31 (4), pp 282 - 285

A radical scavenging compound, 3-pyridinol, in instant coffee and its hepatoprotective activity

Kurakane, S.; Igarashi, K.

In this study, a compound with radical scavenging activity was isolated from roasted instant coffee and it was identified as 3-pyridinol using spectral analysis. It was observed that this compound protected primary cultured rat hepatocytes against cytotoxicity induced by D-galactosamine, indicating that it may prevent liver damage induced by free radicals. However, the authors observe that the amount of 3- pyridinol compared to chlorogenic acid is very small and so the contribution of 3-pyridinol to the hepatoprotective effect of coffee may be less than that of chlorogenic acid.

Source : Food Sci Technol Res 2006 vol. 12 (2), pp 148-151

The coffee diterpene kahweol inhibits tumor necrosis factor-alpha-induced expression of cell adhesion molecules in human endothelial cells

Kim, H. G.; Kim, J. Y.; Hwang, Y. P.; Lee, K. J.; Lee, K. Y.; Kim, D. H.; Kim, D. H.; Jeong, H. G.

Endothelial cells produce adhesion molecules after being stimulated with various inflammatory cytokines. These adhesion molecules play an important role in the development of atherogenesis. Recent studies have highlighted the chemoprotective and anti-inflammatory effects of kahweol, a coffee-specific diterpene. This study examined the effects of kahweol on the cytokine-induced monocyte/human endothelial cell interaction, which is a crucial early event in atherogenesis. Kahweol inhibited the adhesion of TNFalpha-induced monocytes to endothelial cells and suppressed the TNFalpha-induced protein and mRNA expression of the cell adhesion molecules, VCAM-1 and ICAM-1. Furthermore, kahweol inhibited the TNFalpha-induced JAK2-PI3K/Akt-NF-kappaB activation pathway in these cells. Overall, kahweol has anti-inflammatory and anti-atherosclerotic activities, which occurs partly by down-regulating the pathway that affects the expression and interaction of the cell adhesion molecules on endothelial cells.

Source : Toxicol Appl Pharmacol 2006 vol. 217 (3), pp 332 - 341

Joint association of coffee consumption and other factors to the risk of type 2 diabetes: a prospective study in Finland

Hu, G.; Jousilahti, P.; Peltonen, M.; Bidel, S.; Tuomilehto, J.

Joint associations of coffee consumption and other factors (including physical activity, obesity and alcohol consumption) with the risk of type 2 diabetes were investigated. This prospective follow-up study included 10 188 Finnish men and 11 197 women aged 35-74 yr without a history of stroke, coronary heart disease or diabetes at baseline. A self-administered questionnaire gathered data on coffee, tea, alcohol and other food consumption, physical activity, smoking, socio-economic factors and medical history; height, wt. and blood pressure were measured using standardized protocol. During a mean follow-up of 13.4 yr, there were 964 incident cases of type 2 diabetes. Multivariate-adjusted (age, study yr, systolic blood pressure, education, smoking, physical activity, body mass index (BMI) and fruit, vegetable, sausage, bread, alcohol and tea consumption) hazard ratios of type 2 diabetes in participants who drank 0-2, 3-6 and <greater than or equal to>7 cups of coffee were 1.00, 0.77 and 0.66 (P = 0.022 for trend) in men, 1.00, 0.71 and 0.52 (P = 0.001 for trend) in women, and 1.00, 0.75 and 0.61 (P < 0.001 for trend) in men and women combined (adjusted also for sex), respectively. This inverse association was consistent in subjects with any joint levels of physical activity and BMI, and in alcohol drinkers and non-drinkers. Among obese and inactive people, coffee drinking of <greater than or equal to>7 cups daily reduced the risk of type 2 diabetes to half. It is concluded that coffee drinking was associated with a reduced risk of type 2 diabetes in both men and women, and this association was observed regardless of the levels of physical activity, BMI and alcohol consumption.

Source : Intern J Obesity 2006 vol. 30 (12), pp 1742 - 1749

Catechol-o-methyltransferase gene polymorphism modifies the effect of coffee intake on incidence of acute coronary events

Happonen, P.; Voutilainen, S.; Tuomainen, T. P.; Salonen, J. T.

The role of coffee intake as a risk factor for coronary heart disease (CHD) has been debated for decades. We examined whether the relationship between coffee intake and incidence of CHD events is dependent on the metabolism of circulating catecholamines, as determined by functional polymorphism of the catechol-O-methyltransferase (COMT) gene. METHODOLOGY/PRINCIPAL FINDINGS: In a cohort of 773 men who were 42 to 60 years old and free of symptomatic CHD at baseline in 1984-89, 78 participants experienced an acute coronary event during an average follow-up of 13 years. In logistic regression adjusting for age, smoking, family history of CHD, vitamin C deficiency, blood pressure, plasma cholesterol concentration, and diabetes, the odds ratio (90% confidence interval) comparing heavy coffee drinkers with the low activity COMT genotype with those with the high activity or heterozygotic genotypes was 3.2 (1.2-8.4). Urinary adrenaline excretion increased with increasing coffee intake, being over two-fold in heavy drinkers compared with nondrinkers (p = 0.008 for trend).

CONCLUSIONS/SIGNIFICANCE: Heavy coffee consumption increases the incidence of acute coronary events in men with low but not high COMT activity. Further studies are required to determine to which extent circulating catecholamines mediate the relationship between coffee intake and CHD.

Source : PLoS ONE 2006 vol. 1, pp e117

Chlorogenic acid is poorly absorbed, independently of the food matrix: a Caco-2 cells and rat chronic absorption study

Dupas, C.; Marsset-Baglieri, A.; Ordonaud, C.; Tome, D.; Maillard, M. N.

Factors influencing bioavailability of chlorogenic acid (CQA) from coffee, (e.g. addition of milk) were studied and fate of CQA in the gastrointestinal tract was determined on the basis of in vitro digestion of model solutions coupled with Caco-2 cell absorption studies. Animal feeding studies were also carried out in which rats were administered coffee (with or without milk) for 3 wk. Interactions were observed between milk proteins CQA (as determined by an ultrafiltration method) and these interactions were shown to be disrupted during in vitro digestion. Subsequent rat feeding trials and studies on Caco-2 cells coupled with in vitro digestion demonstrated that CQA is poorly absorbed in its native form and absorption is unaffected by addition of milk proteins and slightly decreased by addition of Maillard reaction products. It is concluded that interaction of coffee phenols with milk proteins does not appear to significantly influence CQA bioavailability from coffee.

Source : Mol Nutr Food Res 2006 vol. 50 (11), 1053 – 1060

The magnitude of bias in a cross-sectional study on lifestyle factors in relation to Type 2 diabetes

Agardh, E. E.; Ahlbom, A.; Andersson, T.; Ostenson, C. G.

In cross-sectional studies it may be difficult to ascertain the temporal order of exposure and disease, which may have consequences for causal inference. The authors aimed to illustrate the possible magnitude of this potential bias using data from a cross-sectional study on coffee consumption and work stress in relation to type 2 diabetes. METHODS: By a series of computer simulations the authors examined to what extent the observed negative association between type 2 diabetes and high coffee consumption and positive association between type 2 diabetes and high work stress could be due to reverse causality, by assuming that cases changed their exposures in response to development of the disease. RESULTS: If the negative association between coffee and type 2 diabetes was a consequence of reversed causality, 30-40% of the cases would have to decrease their coffee consumption from 5 cups of coffee per day to 3-4 cups per day and from 3-4 cups per day to 2 cups of coffee per day. Moreover, approximately 60% of the cases would have to increase their work stress from low to medium work stress and from medium to high work stress, in order to produce the positive association with diabetes that was observed.

CONCLUSION: Even if the type 2 diabetic patients to some extent may have changed their exposure in response to disease development, it seems unlikely that the associations observed between type 2 diabetes, coffee consumption, and work stress are due to this bias.

Source : Scand J Public Health 2006 vol. 34 (6), pp 665 - 668

Inverse association between coffee drinking and the risk of hepatocellular carcinoma: a case-control study in Japan

Tanaka, K.; Hara, M.; Sakamoto, T.; Higaki, Y.; Mizuta, T.; Eguchi, Y.; Yasutake, T.; Ozaki, I.; Yamamoto, K.; Onohara, S.; Kawazoe, S.; Shigematsu, H.; Koizumi, S.

Coffee use has consistently been associated with lower serum liver enzyme levels and a reduced risk of liver cirrhosis. A limited number of cohort and case-control studies also suggest a decreased risk of hepatocellular carcinoma (HCC) among coffee drinkers, but mostly without consideration of hepatitis virus infection. In the present case-control study, we recruited 209 incident HCC cases and three different controls (1308 community controls, 275 hospital controls, and 381 patients with chronic liver disease [CLD] without HCC), all of whom were aged 40-79 years and residents of Saga Prefecture, Japan. A questionnaire survey elicited information on coffee use during the last 1-2 years and 10 years before, and plasma hepatitis B surface antigen and antibodies to hepatitis C virus were tested for all but community controls. After adjustment for sex, age, heavy alcohol use, smoking status and hepatitis virus markers (except for community controls), coffee use during the last 1-2 years was associated with a decreased risk against any control group. For coffee use 10 years before, comparison between HCC cases and either community controls or CLD patients revealed a decreased risk; adjusted odds ratios for occasional use, 1-2 cups/day and >/=3 cups/day compared with no use were 0.33, 0.27 and 0.22 (P trend < 0.001), respectively, against community controls, and 0.86, 0.62 and 0.53 (P trend = 0.05), respectively, against CLD patients. These results suggest that coffee may protect against the development of HCC, yet further elaborate studies (hopefully, intervention studies) are warranted to corroborate these findings.

Source : Cancer Sci 2007 vol .98 (2), pp 214 – 218

Schutzt Kaffee die Leber? [Does coffee protect the liver?]

Smoliner, C.; Norman, K.; Pirlich, M.

A commentary.

Source : Z Gastroenterol 2007 vol. 45 (1), pp 87 - 88

Coffee, caffeine, and coronary heart disease

Cornelis, M. C.; El Sohemy, A.

This review summarizes and highlights recent advances in current knowledge of the relationship between coffee and caffeine consumption and risk of coronary heart disease. Potential mechanisms and genetic modifiers of this relationship are also discussed. RECENT FINDINGS: Studies examining the association between coffee consumption and coronary heart disease have been inconclusive. Coffee is a complex mixture of compounds that may have either beneficial or harmful effects on the cardiovascular system. Randomized controlled trials have confirmed the cholesterol-raising effect of diterpenes present in boiled coffee, which may contribute to the risk of coronary heart disease associated with unfiltered coffee consumption. A recent study examining the relationship between coffee and risk of myocardial infarction incorporated a genetic polymorphism associated with a slower rate of caffeine metabolism and provides strong evidence that caffeine also affects risk of coronary heart disease. Several studies have reported a protective effect of moderate coffee consumption, which suggests that coffee contains other compounds that may be beneficial.

CONCLUSIONS : Diterpenes present in unfiltered coffee and caffeine each appear to increase risk of coronary heart disease. A lower risk of coronary heart disease among moderate coffee drinkers might be due to antioxidants found in coffee.

Source : Curr Opin Lipidol 2007 vol. 18 (1), pp 13 – 19

Coffee. Is it good or bad for you?

Anon.

Like much-publicized green tea, which has garnered considerable attention due to its high antioxidant content, researchers have found that coffee is quite high in antioxidants. Antioxidants are generally helpful substances, found in foods, which scavenge unstable molecules (free radicals) in your body. Free radicals contribute to oxidative stress, which, over time, can cause inflammation and other unhealthy changes in your cells. The February issue of Mayo Clinic Women's HealthSource highlights news about these health benefits of coffee.
Source : Mayo Clin Womens Healthsource 2007 vol. 11 (2), pp 7