Nagai, C.; Rakotomalala, J. J.; Katahira, R.; Yeyun, Li; Yamagata, K.; Ashihara, H.
GCAs are new tetraploid interspecific coffee hybrids developed in Madagascar from Coffea eugenioides, C. canephora and C. arabica. The GCA with the genotype UF1023 was selected for metabolic studies, and contained 0.37% DW caffeine and no detectable theobromine in its green coffee beans. It is suggested that low caffeine accumulation in GCA plants is mainly due to low biosynthetic activity of purine alkaloids, possibly because of extremely weak N-methyltransferase reactions in caffeine biosynthesis. No significant catabolic activity of caffeine was found in GCA-UF1023, in common with almost all coffee plants including C. arabica.
Bosselmann, A. S.; Dons, K.; Oberthur, T.; Smith-Olsen, C.; Raebild, A.; Usma, H.
Production of coffee, especially by small holders, is often associated with various forms of shade management. To analyse the effects of shade on physical coffee quality and on sensorial cup quality of Coffea arabica L. cv. Caturra KMC, a study was carried out with 94 plots on 16 farms in two municipalities, Timaná and Oporapa, located at elevations from 1272 to 1730 masl. in Huila, Colombia. The study was designed with emphasis on shade cover variation within each of the two study areas, while minimizing the variability of environment, agronomic management other than shade, and post-harvest processing. 46 samples of shade coffee and 46 samples of sun coffee were evaluated for physical and sensorial attributes using three professional coffee cuppers (assessors). A principal component analysis including all quality and environmental variables showed that sensory attributes were influenced negatively by shade, and that physical attributes were influenced positively by altitude. A mixed linear model, with coffee cupper and farm as random variables, revealed different shade effects on coffee quality in the two areas. In Oporapa, situated at high altitudes, shade had a negative effect on fragrance, acidity, body, sweetness and preference of the beverage, while no effect was found on the physical quality. In Timaná, situated at lower altitudes, shade did not have a significant effect on sensorial attributes, but significantly reduced the number of small beans. At high altitudes with low temperatures and no nutrient or water deficits, shade trees may thus have a partly adverse effect on C. arabica cv. Caturra resulting in reduced sensory quality. The occurrence of berry borer (Hypothenemus hampei) was lower at high altitudes and higher under shade. Future studies on shade and coffee quality should focus on the interaction between physical and chemical characteristics of beans.
Source : Agriculture Ecosystems & Environment 2009 vol. 129 (1-3), pp 253 - 260
Ferreira-Silva, C.; Roberto-Batista, L.; Freitas-Schwan, R.
The objective of this work was to isolate and characterize filamentous fungi present in different stages of harvest, fermentation, drying and storage of coffee beans processed by natural methods. The cherries were hand-picked and then placed on a cement drying platform where they were dried to 11% humidity. Microbial counts were found in all samples during fermentation and drying of the coffee beans. Counts of fungi in the coffee cherries collected from the tree (time 0) were around 1.5 x 103 cfu/g. This number increased slowly during the fermentation and drying reaching values of 2 x 105 cfu/g within 22 days of processing. 263 isolates of filamentous fungi were identified. The distribution of species during fermentation and drying was very varied while there was a predominance of Aspergillus spp. during the storage period. The genera found were Pestalotia (n = 4), Paecelomyces (n = 4), Cladosporium (n = 26), Fusarium (n = 34), Penicillium (n = 81) and Aspergillus (n = 112) and comprised 38 different species.
Noonim, P.; Mahakarnchanakul, W.; Nielsen, K. F.; Frisvad, J. C.; Samson, R. A.
The distribution of fungi with potential to produce ochratoxin A (OTA) in Thai dried coffee-bean samples (Coffea arabica and Coffea canephora var. robusta) obtained from two growing sites in Thailand was investigated, together with the presence of OTA in coffee bean samples. Fungal contamination assessed as 98% in coffee beans was reduced to 60% after surface disinfection. Arabica coffee bean samples from northern Thailand showed an average 78% incidence of colonisation with Aspergillus, the predominant species being Aspergillus westerdijkiae and Aspergillus melleus, while Aspergillus species of the section Nigri were found in 75% of samples. Robusta coffee beans from southern Thailand were 98 to 100% contaminated with mainly Aspergillus carbonarius and Aspergillus niger. Large amounts of OTA were produced by Aspergillus westerdijkiae, Aspergillus steynii and Aspergillus carbonarius. Of 64 coffee bean samples analysed, 98% were contaminated with OTA at levels of less than 0.6 to 5.5 mcg/kg (Arabica) and 1 to 27 mcg/kg (Robusta).
Magnoli, C. E.; Astoreca, A. L.; Ponsone, M. L.; Barberis, C. L.; Fernandez-Juri, M. G.; Dalcero, A. M.
The aims of this work were to identify the Aspergillus sections Nigri and Flavi, and to evaluate the natural occurrence of ochratoxin A (OTA) and aflatoxins in green and roasted coffee bean samples. The capacity to produce these toxins by Aspergillus spp. was also studied. 50 samples of Colombian coffee beans (25 green and 25 roasted) were obtained from a factory located in the south of Cordoba province, Argentina. OTA and aflatoxin analysis were performed by HPLC. OTA production by strains belonging to Aspergillus niger aggregate were cultivated using YES medium and detected by HPLC. Aflatoxin production
was tested in strains belonging to section Flavi on malt extract agar and was detected by TLC. From green coffee samples, the predominant species isolated belonged to A. niger aggregate, 60 and 55%, in dichloran rose bengal chloramphenicol agar (DRBC) and dichloran 18% glycerol agar (DG18) respectively. While A. flavus strains were isolated in 14% from DRBC and A. parasiticus strains in 12 and 28% in DRBC and DG18, respectively. From roasted coffee samples, A. flavus was the most predominant fungi, isolated in similar percentages from both media (28%); followed by A. niger aggregate isolated in 28 and 14% in DRBC and DG18, respectively. In green and roasted coffee samples mean colony counts ranged from 2 x 103 to 3.5 x104 cfu/g. OTA and aflatoxins were not detected in any sample analyses (<1 and 0.5 ng/g for OTA and aflatoxins, respectively). 25% of black Aspergillus strains were OTA producers. The total of A. flavus strains assayed produced aflotoxin B1 (AFB1) and 80% of the A. parasiticus strains were AFB1 and aflotoxin G1 producers. It is concluded that the high percentage of A. flavus and A. parasiticus aflatoxin-producing strains suggest a potential risk for contamination in coffee with aflatoxins.
Source : World Mycotoxin Journal 2008 vol.1 (4), pp 419 - 427
Tokumura, M.; Znad, H. T.; Kawase, Y.
Use of a solar radiation-assisted photo Fenton process for decoloration of coffee effluents was studied. Effects of accumulated solar radiation energy and Fe and H2O2 dosage on brown colour removal was assessed and decoloration kinetics were determined under different weather conditions. Decoloration rate increased to Fe and H2O2 dosages of <less than or equal to>10 and 1000 mg/l, with excess dosages unable to bring further improvement in colour removal. Mineralization of coffee effluents was also studied and shown to proceed more slowly than decoloration. Solar radiation had a similar decoloration capability to UV radiation. Overall results indicated that solar-assisted photo-Fenton reaction is an efficient means for decoloration of dark-brown colour coffee effluents. Kinetic constants could be easily used to assess amount of solar energy required to achieve a given degree of colour removal.
Silva, C. F.; Batista, L. R.; Abreu, L. M.; Dias, E. S.; Schwan, R. F.
Information on the microbial dynamics during the natural fermentation of coffee would allow more rapid fermentation and improve the quality of the final product. This study investigated the natural microbial fermentation of coffee cherries, and isolated and characterised the microorganisms involved. The biochemical characteristics of coffee during fermentation, drying and storage were also examined. Genera and species identified are listed; these included members known to have pectinase and cellulase activities. The authors suggest that acetic and lactic acids might have been generated by microbial activity.
Montandon, G.; Kinkead, R.; Bairam, A.
Caffeine is an adenosine receptor antagonist that is commonly used in the clinic as a respiratory stimulant to treat apnea of prematurity. A recent clinical study showed that newborns treated with caffeine present no neuro-developmental disabilities at 2 years of age in comparison to placebo-treated children [Schmidt, B., Roberts, R.S., Davis, P., Doyle, L.W., Barrington, K.J., Ohlsson, A., Solimano, A., Tin, W., 2007. Long-term effects of caffeine therapy for apnea of prematurity. N. Engl. J. Med. 357, 1893-1902]. Although neonatal caffeine administration in this population is associated with clear short- and long-term health improvements, the consequences of this treatment on basic homeostatic functions such as respiratory regulation are unknown. This article reviews evidence indicating that neonatal caffeine treatment modifies respiratory control development and that these changes persist until adulthood. The mechanisms contributing to this form of developmental plasticity are unknown but current data indicate that caffeine treatment, especially during the perinatal period, alters adenosinergic neuromodulation of the respiratory control system. While human data show that neonatal caffeine treatment is relatively safe for some aspects of neural development, the results obtained in animal studies raise important questions pertaining to the potential long-term effects of this treatment on the respiratory control system.
Source : Respir Physiol Neurobiol 2008 vol.164 (1-2), pp 87 - 95
Pelucchi, C.; Vecchia, C. la
Epidemiological studies were reviewed that evaluated the association between consumption of coffee and alcohol, and urinary bladder cancer. The Medline database was searched for observational studies of bladder neoplasms that included information on coffee or alcohol drinking, and looked for papers quoted as references in reviews of risk factors for bladder cancer and in studies that had been selected for inclusion. Results from epidemiological studies allowed excluding a strong association between coffee and bladder cancer. Several studies reported a moderate increase in risk in coffee drinkers as compared with nondrinkers, but no trend with dose has been established. Epidemiological data on alcohol drinking and bladder cancer were suggestive of no association, although findings were not always consistent. For both habits, an explanation of the moderate increase in risk observed in some investigations might be attributed to residual confounding by smoking, or to an association between alcohol, coffee, and yet unidentified risk factors for bladder cancer.
Eun, Sun Cho; Young, Jin Jang; Mun, Kyung Hwang; Nam, Joo Kang; Ki, Won Lee; Hyong, Joo Lee
Neurodegenerative disorders such as Alzheimer\'s disease (AD) are strongly associated with oxidative stress, which is induced by reactive oxygen species (ROS) including hydrogen peroxide (H2O2). Recent studies suggest that moderate coffee consumption may reduce the risk of neurodegenerative diseases such as AD, but the molecular mechanisms underlying this effect remain to be clarified. In this study, we investigated the protective effects of chlorogenic acid (5-O-caffeoylquinic acid; CGA), a major phenolic phytochemical found in instant decaffeinated coffee (IDC), and IDC against oxidative PC12 neuronal cell death. IDC (1 and 5 μg/ml) or CGA (1 and 5 μM) attenuated H2O2-induced PC12 cell death. H2O2-induced nuclear condensation and DNA fragmentation were strongly inhibited by pretreatment with IDC or CGA. Pretreatment with IDC or CGA also inhibited the H2O2-induced cleavage of poly(ADP-ribose) polymerase (PARP), and downregulation of Bcl-XL and caspase-3. The accumulation of intracellular ROS in H2O2-treated PC12 cells was dose-dependently diminished by IDC or CGA. The activation of c-Jun N-terminal protein kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) by H2O2 in PC12 cells was also inhibited by IDC or CGA. Collectively, these results indicate that IDC and CGA protect PC12 cells from H2O2-induced apoptosis by blocking the accumulation of intracellular ROS and the activation of MAPKs.
Source : Mutat Res Fund & Mol Mech Mutage 2009 vol.661 (1-2), pp 18 - 24
Silletta, M. G.; Marchioli, R.
Many epidemiological studies have addressed the effects of coffee on cardiovascular disease. Most case-control studies suggest an increased risk in high coffee consumers, whereas cohort studies indicate no clear association with cardiovascular risk. Several aspects could be considered to explain and/or reconcile these inconsistencies. Selection bias and recall bias may explain a positive association supported by case-control studies. An inadequate adjustment for many confounding factors (i.e., smoking, poor diet, sedentary lifestyle, etc.) could also affect the relationship between coffee consumption and cardiovascular risk. Moreover, coffee contains several biologically active substances that may have either beneficial or harmful effects on the cardiovascular system. The development of complete/partial tolerance to some caffeine effects in habitual drinkers adds to the complexity of coffee effects. Variation in cup size and methods of coffee preparation may also explain some conflicting results. At it is not reasonable to develop randomized controlled trials, hence it is recommended that coffee consumption be moderate in healthy people and limited in individuals at high risk.
Source : Recenti Prog Med vol.99 (11), pp 533 - 537
Nagatomo, K.; Kubo, Y.
Caffeine has various well-characterized pharmacological effects, but in mammals there are no known plasma membrane receptors or ion channels activated by caffeine. It was observed that caffeine activates mouse transient receptor potential A1 (TRPA1) in heterologous expression systems by Cai2+ imaging and electrophysiological analyses. These responses to caffeine were confirmed in acutely dissociated dorsal root ganglion sensory neurons from WT mice, which are known to express TRPA1, but were not seen in neurons from TRPA1 knockout mice. Expression of TRPA1 was detected immunohistochemically in nerve fibres and bundles in the mouse tongue. Moreover, WT mice, but not knockout mice, showed a remarkable aversion to caffeine-containing water. These results demonstrate that mouse TRPA1 channels expressed in sensory neurons cause an aversion to drinking caffeine-containing water, suggesting they mediate the perception of caffeine. Finally, it was observed that caffeine does not activate human TRPA1; instead, it suppresses its activity.
Source : Proc Nat Acad Sci USA 2008 vol.105 (45), pp 17373 - 17378
Kot, M.; Daniel, W. A.
The current knowledge on the involvement of cytochrome P450 (P450, CYP) isoforms in the metabolism of caffeine in rat and human liver is reviewed. Attention is also paid to species- and concentration-dependent metabolism of caffeine. Finally, we discuss the P450-mediated metabolism of caffeine in relation to coffee addiction and drug interactions. Due to its safety, favorable pharmacokinetic properties, and P450 isoform-selective metabolism, caffeine has great potential as a metabolic marker substance in both humans and rats, and as a more universal metabolic tool in the latter species. However, the qualitative and relative quantitative contribution of P450 isoforms to the metabolism of caffeine is species- and concentration-dependent. While 3-N-demethylation is quantitatively the main oxidation pathway in human, 8-hydroxylation is the dominant metabolic pathway in rat. Both of these main reactions in the two species are specifically catalyzed by CYP1A2. Caffeine may be applied as a marker substance for assessing the activity of CYP1A2 in human and rat liver, but by using different reactions: 3-N-demethylation in humans and C-8-hydroxylation in rats. In addition, caffeine can be used to preliminarily and simultaneously estimate CYP2C activity in rat liver using 7-N-demethylation as a marker reaction. On the other hand, CYP3A4-catalyzed 8-hydroxylation in humans is not sufficiently isoform-specific to mark the activity of CYP3A4. Caffeine pharmacokinetics may be changed by drugs affecting the activity of CYP1A2 (human and rat) or CYP2C (rat), e.g. via autoinduction or by treatment with certain antidepressants or neuroleptics. Therefore, patients taking caffeine-containing medicine or coffee drinkers taking drugs that interact with CYP1A2 may require proper dosage adjustments upon caffeine ingestion and cessation.
Tieges, Z.; Snel, J.; Kok, A.; Richard-Ridderinkhof, K.
The effects of a 3mg/kg body weight (BW) dose of caffeine were assessed on behavioral indices of response inhibition. To meet these aims, we selected a modified AX version of the Continuous Performance Test (CPT), the stop task, and the flanker task. In three double-blind, placebo-controlled, within-subjects experiments, these tasks were administered to healthy participants. While the results for the AX-CPT were indicative of improved response inhibition after caffeine, they might also reflect caffeine-induced changes in mechanisms other than response inhibition (e.g., attentional processes). The results for the stop task and flanker task were more straightforward. That is, the effects of caffeine on overall flanker performance and selective response suppression as revealed by distribution-analytical techniques were negligible. In the stop task a global effect of caffeine on processing speed was seen, rather than specific effects on response inhibition. Taken together, these experiments showed that both active and reactive inhibition were not significantly modulated by caffeine. The present results are linked to neural circuits that underlie inhibitory control and the role of caffeine-induced strategic changes.
Kagami, K.; Onda, K.; Hirano, T.; Oka, K.
This study compared the ability of nicotinic acid (NA), which is found in roasted coffee, to lower plasma non-esterified fatty acid (NEFA) levels with that of the Maillard reaction product 2,5-dimethylpyrazine (2,5-DMP), which is metabolised in the liver to 5-methylpyrazinoic acid, a compound that, like NA, which binds to G protein-coupled receptor GPR109A. The rebound phenomenon observed with NA was not found with 2,5-DMP or mixtures of 2,5-DMP and NA, suggesting that co-administration of 2,5-DMP and other Maillard reaction products with NA can result in continuous low plasma NEFA concentrations.
Terry, P.; Doumas, M.; Desai, R. I.; Wing, A. M.
The impacts of psychoactive drugs on timing have usefully informed theories of timing and its substrates. OBJECTIVES: The objectives of the study are to test the effects of alcohol and caffeine on the explicit timing involved in tapping with the implicit timing observed in the coordinated picking up of an object, and with the temporal discrimination. MATERIALS AND METHODS: Participants in the "alcohol" experiment (N = 16) received placebo, "low" (0.12 g/kg or 0.14 g/kg for women/men, respectively) or "high" (0.37 g/kg or 0.42 g/kg, respectively) doses of alcohol, and those in the "caffeine" experiment (N = 16) received placebo, 200 or 400 mg caffeine. Time production variability was measured by repetitive tapping of specified intervals, and sources of variance attributable to central timer processes and peripheral motor implementation were dissociated. The explicit timing in tapping was compared with the implicit timing in the coordinated picking up of an object. Time perception was measured as discrimination thresholds for intervals of similar duration. Drug effects on reaction time were also measured. RESULTS: For tapping, alcohol significantly increased timer variability, but not motor variability; it did not affect coordination timing in the grip-lift task. Conversely, for time perception, the low dose of alcohol improved temporal discrimination. Caffeine produced no effects on any of the timing tasks, despite significantly reducing reaction times.
CONCLUSIONS: The effects of alcohol argue against a common clock process underlying time interval perception and production in the range below 1 s. In contrast to reaction time measures, time perception and time production appear relatively insensitive to caffeine.
Source : Psychopharmacology (Berl) 2009 vol.202 (4), pp 719 - 729
Geleijnse, J. M.
This paper summarizes the current epidemiological evidence on coffee consumption in relation to blood pressure (BP) and risk of hypertension. Data from cross-sectional studies suggest an inverse linear or U-shaped association of habitual coffee use with BP in different populations. Prospective studies suggest a protective effect of high coffee intake (4 or more cups per day) against hypertension, mainly in women. Furthermore, the risk of hypertension may be lower in coffee abstainers. Randomized controlled trials, which are mostly of short duration (1-12 weeks), have shown that coffee intake around 5 cups per day causes a small elevation in BP (approximately 2/1 mmHg) when compared to abstinence or use of decaffeinated coffee. With regard to underlying biological mechanisms, most research has been devoted to BP-raising effects of caffeine. However, there are many other substances in coffee, such as polyphenols, soluble fibre and potassium, which could exert a beneficial effect in the cardiovascular system. Although the precise nature of the relation between coffee and BP is still unclear, most evidence suggests that regular intake of caffeinated coffee does not increase the risk of hypertension.
Source : Vasc Health Risk Manag. 2008 vol.4 (5), pp 963 - 970 (full text)
Anup, Mandal; Poddar, M. K.
Caffeine, the active principle alkaloid of coffee and tea, inhibits tumour-induced suppression of the specific immune response in adult mice. Effects of long-term consumption of caffeine in the development of Ehrlich ascites carcinoma (EAC) cells in adult Swiss female mice, in relation to the innate immune response and tumour growth, were determined. Although consumption of caffeine alone for >12 consecutive days did not affect innate immune response parameters, continuation of its treatment following intraperitoneal EAC cell inoculation reduced in vivo tumour growth and reduced/restored the EAC cell-induced suppression of the innate immune response. Results suggest that caffeine may inhibit in vivo tumour growth through reduction of the cancer cell-induced suppression of the innate immune response.
Care-Study-Group
It has been suggested that overconsumption of caffeine during pregnancy might contribute towards lowered birth weight. This study aimed to investigate the effects of maternal caffeine intake on foetal growth. The study involved 2,635 pregnant women, whose caffeine intake was assessed from 4 weeks prior to pregnancy and during the course of the pregnancy. It was found that caffeine intake throughout pregnancy of more that 300 mg/day was associated with an increased risk of foetal growth restriction compared with a caffeine intake throughout pregnancy of less than 100 mg/day. It is recommended that advice be given to pregnant women in order to help them limit caffeine intake during pregnancy.
Source : Brit Med J 2008 vol.8, 337 (7678), a2332 (full text)
Binns, C. W.; Lee, A. H.; Fraser, M. L.
The level of evidence required to justify giving dietary advice to the public was investigated, with particular reference to tea and coffee consumption. There are important practical differences between the development of public health nutrition guidelines and guidelines for clinical practice. While the gold standard for evidence for clinical practice guidelines is a meta-analysis of a number of randomised controlled trials, this is often unrealistic and sometimes unethical for the evaluation of public health nutrition interventions. Hence, epidemiological studies make up the bulk of evidence for nutrition guidelines. Tea and coffee are an interesting case study in relation to this issue. They are 2 of the most commonly consumed beverages worldwide, yet there is little dietary advice on their use. The evidence for a relationship between coffee or tea consumption and several diseases is discussed. The available studies, predominantly epidemiological, together with animal and in vitro studies, indicate that coffee and tea are both safe beverages. However, tea is the healthier option because it has a possible role in the prevention of several cancers and CVD. While the evidence for such relationships is not strong, the public will continue to drink both tea and coffee, and will continue to ask nutritionists to make recommendations. It is therefore argued that advice should be given on the best available data, as waiting for complete data to become available could have severe consequences for public health.
Source : Public Health Nutrition 2008 vol.11 (11), pp 1132 - 1141
McNaughton, L. R.; Lovell, R. J.; Siegler, J.; Midgley, A. W.; Moore, L.; Bentley, D. J.
The purpose of this work was to determine the effects of caffeine on high intensity time trial (TT) cycling performance in well-trained subjects. Subjects: Six male cyclists with the following physical characteristics (mean +/- SD) age 30.7 +/- 12, height 179.3 +/- 7.5 cm, mass 70.0 +/- 7.5 kg, VO2max 65.0 +/- 6.3 mL.kg-1.min-1 undertook three 1-h TT performances, control (C), placebo (P) and caffeine (CAF), on a Velotron cycle ergometer conducted in a double-blind, random fashion. Subjects rested for 60 min and were then given CAF or P in a dose of 6 mg.kg-1 body mass and then commenced exercise after another 60 min of rest. Before ingestion, 60 min postingestion, and at the end of the TT, finger-prick blood samples were analyzed for lactate. Results: The cyclists rode significantly further in the CAF trial (28.0 +/- 1.3 km) than they did in the C (26.3 +/- 1.5 km, P < .01) or P (26.4 +/- 1.5 km, P < .02) trials. No differences were seen in heart rate data throughout the TT (P > .05). Blood lactate levels were significantly higher at the end of the trials than either at rest or postingestion (P < .0001), but there were no differences between the three trial groups. Conclusion: On the basis of the data, we concluded that performance was improved with the use of a caffeine supplement.
Source : Int J Sports Physiol Perform 2008 vol.3 (2), pp 157 - 163
Ofluoglu, E.; Pasaoglu, H.; Pasaoglu, A.
In our study, the short-term effects of caffeine on L-arginine metabolism in the brains of rats were investigated. Caffeine was given orally at two different doses: 30 mg/kg and 100 mg/kg (a high non-toxic dose). Brain tissue arginase activity in rats from the caffeine-treated groups decreased significantly compared with the control group. Malondialdehyde (MDA) levels in the brain tissue and serum of animals in the caffeine groups also decreased significantly. Brain tissue and serum nitric oxide (NO) levels increased significantly after caffeine administration. Tumor necrosis factor-alpha (TNF-alpha) levels were also investigated in rat serum, but there was no statistically significant difference between the TNF-alpha levels of the caffeine-treated rats groups and the control rats. Our study indicates that brain arginase activity decreases after caffeine administration at doses of 30 mg/kg and 100 mg/kg. As a result, we can say that arginine induces production of NO in the organism.
Marin, K.; Pozrl, T.; Zlatic, E.; Plestenjak, A.
The staling of a ground roasted coffee blend was studied over 1 yr of storage. Solid phase microextraction GC-MS was carried out to identify and semi-quantify 40 volatile compounds. The study focused on volatile compounds related to the ageing of coffee: methanethiol, propanal, 2-methylfuran, 2-butanone, 2,3-butanedione, 2-furfurylthiol and hexanal. Changes in sensory properties of coffee beverages prepared from the ground roasted coffee samples during storage in laminate packages (PET/ aluminium foil/PE) under air, under N2 or in punctured packages were determined. Samples were stored at approx. 23°C and 40% RH. The reference coffee was packed similarly in laminate packages under N2 and stored at -20°C. Statistical analysis revealed the loss of most volatile compounds from all stored coffee samples, including even those stored under freezing conditions. 2-methylfuran/2-butanone and methanethiol/hexanal ratios proved to be useful indicators of staling. A new proposed aroma index, the 2-furfurylthiol/hexanal ratio, proved to be the most effective, giving high correlation coeff. (R = 0.80) with aroma freshness for coffee brews prepared from the ground roasted coffee stored under different conditions at room temp.
Source : Food Technol Biotechnol 2008 vol.46 (4), pp 442 - 447
Gornas, P.; Neunert, G.; Baczynski, K.; Polewski, K.
Coffee brew is rich in chlorogenic and cinnamic acids, potent antioxidants. Its interaction with beta-cyclodextrin leads to formation of inclusion complexes which affect the physicochemical properties of the guest molecule. We investigated spectral changes in coffee-originated phenols, chlorogenic (CHA) and caffeic (CA) acids, due to complexation with beta-cyclodextrin (betaCD) in aqueous solutions and studied thermodynamic properties of the complexes formed. The spectroscopic data (absorption and fluorescence) were used for deducing the position of both phenols inside the beta-cyclodextrin cavity, as well as to calculate the binding constants of the complexes. The obtained data indicate the formation of a 1:1 complex between betaCD and CHA or CA. The temperature-dependence of the latter allowed the calculation of thermodynamic parameters (DELTAH, DELTAS and DELTAG) of the complexation. The negative values of all the thermodynamic parameters indicated that the formation of these inclusion complexes was an enthalpy-driven process in which a crucial role is played by weak van der Waals forces and hydrogen bonds. Molecular modelling confirmed experimental observations that, in aqueous phase, betaCD-CHA and -CA complexes are stable and energetically favourable, and additionally provided information regarding conformation and interaction between atoms forming the complexes. The experimental data were used to characterise the molecular mechanism of the complexation.
Allard, E.; Backstrom, D.; Danielsson, R.; Sjoberg, P.-J. R.; Bergquist, J.
Metabolomic fingerprinting is a growing strategy for characterizing complex biological samples without detailed prior knowledge about the metabolic system. A 2-way analysis system with liquid separation and MS detection provides detail-rich data suitable for such fingerprints. As a model study, human urine samples, obtained after intake of coffee, tea or water, were analysed with capillary electrophoresis electrospray ionization time-of-flight MS (CE-ESI-TOF-MS). In-house-developed software (in Matlab) was utilized to manage and explore the large amount of data acquired (230 CE-MS runs, each with 50-100 million nonzero data points). After baseline and noise reduction, followed by suitable binning in time and m/z, the data sets comprised 9 and 14 million data points in negative and positive ESI mode, respectively. Finally, a signal threshold was applied, further reducing the number to approx. 100 000 data points per data set. A set of interactive exploratory tools, utilizing principal component analysis (PCA) and analysis of variance (ANOVA) results based on a general linear model, facilitated visual interpretation with score plots (for group assessment) and differential fingerprints (for \'hot spot\' detection). In the model study highly significant differences due to beverage intake were obtained among the 10 first principal components (P < 10-6 for 2 of the components in both ESI modes). Especially, the contrasts between \'coffee\' and \'tea or water\' indicated several \'hot spots\' with highly elevated intensities (e.g., for uncharged masses 93, 94, 109, 119, 123, 132, 148, 169, 178, 187, 190 and 193) suitable for further analysis, for example, with tandem MS.
Alves, R. C.; Casal, S.; Alves, M. R.; Oliveira, M. B.
extraction method was used, and the quantification performed by normal-phase HPLC/diode-array/fluorescence detection. Regarding green arabicas, the mean contents were 2.7 ± 0.4 mg/100 g, for alpha-tocopherol, and 8.0 ± 0.9 mg/100 g, for beta-tocopherol. For green robustas, mean values of 1.7 ± 0.3 and 2.1 ± 0.3 mg/100 g were found for alpha- and beta-tocopherol, respectively. Generally, more than 90% of tocopherols remained after the roasting procedure, except for beta-tocopherol in robustas, whose mean degradation was approximately 25% when expressed as dry weight. No gamma-tocopherol was detected in any sample. The results show that tocopherol profile could be useful in the discrimination of arabica and robusta coffees (either green or roasted).
Sacchetti, G.; Di Mattia, C.; Pittia, P.; Mastrocola, D.
Coffee is a major source of antioxidants, but these can be affected by processing conditions. This study investigated the relationships between the free-radical-scavenging activity (FRSA) of coffee brews obtained from different types of coffee, and the roasting degree. It was found that brews extracted from medium-roasted coffee had higher FRSA than those from green coffee. This was attributed to roasting increasing the levels of Maillard reaction products (MRPs) with antioxidant activity. Further roasting to produce dark coffee gave brews with lower FRSA as a result of polyphenol degradation, the contribution of MRPs to FRSA being much lower than that of the polyphenols. Roasting processes with the same equivalent thermal effect values gave coffee with similar FRSA, independent of average temperature (170-190 C) and coffee type. Antioxidant activity was found to be more dependent on roasting severity than coffee type.
Source : J Food Eng 2009 vol.90 (1), pp 74-80
Jinhua, Zhu; Shengda, Qi; Jinhua, Li; Xingguo, Chen
Use of different stacking methods (low temp. bath or high conductivity zone) for optimizing micellar electrokinetic chromatography (MEKC) in terms of sample injection vol. and analyte zone was studied and used for MEKC analysis of model phenols (chlorogenic, caffeic and ferulic acids) in coffee beverages. Low temp. bath enabled large sample injection vol. to be achieved by subjecting part of the capillary to low-temp. immersion, resulting in a pseudo low-conductivity zone. The high-conductivity zone was inserted between the sample zone and background solution resulting in an unequal conductivity gradient. Detection limit for chlorogenic acid in coffee (0.31 mug/ml using normal MEKC with suppressed electroosmotic flow) was improved to 2.8 x 10-2, 5.3 x 10-3 and 6.0 x 10-3 mug/ml, respectively, using normal MEKC-stacking, high conductivity zone MEKC-stacking and low temp. zone MEKC stacking, respectively. When both high conductivity zone and low temp. zones were used simultaneously on a single capillary, synergistic effects on stacking efficiency were noted for chlorogenic and caffeic acids, but not for ferulic acid.
Lang, R.; Yagar, E. F.; Eggers, R.; Hofmann, T.
A straightforward stable isotope dilution analysis (SIDA) for the quantitative determination of trigonelline, nicotinic acid and nicotinamide in foods such as coffee, as well as in biological samples, by means of LC-MS/MS (MRM) was developed. The coeff. of variation for their quantitative analysis in a coffee sample were 2.1% for trigonelline, 1.1% for nicotinic acid and 3.1% for nicotinamide, and recovery experiments showed good results between 98.5 and 104.5%. Application of this SIDA for the quantification of trigonelline, nicotinic acid and nicotinamide in coffee samples of different roasting degrees revealed a drastic degradation of trigonelline as well as the generation of nicotinic acid accounting for 4-6% of the initial trigonelline content, whereas nicotinamide remained rather constant at a low level. Besides the analysis of coffee samples, the feasibility of the developed SIDA was verified by analysis of other foods including breakfast cereals, rice, cattle liver and herring, as well as human urine and plasma samples.
Source : J Agric Food Chem 2008 vol.56 (23), pp 11114 - 11121
Guerra, S.; Lagazio, C.; Manzocco, L.; Barnaba, M.; Cappuccio, R.
Sensory evaluation is used to predict the shelf life of products, and the subjectivity in the choice of some parameters for data collection and analysis can affect the final result. Typical problems to be avoided when planning the test and analysing data are considered in this study. Commonly used techniques in sensory data processing for predicting shelf life are compared, and the effects of the choice of acceptability limits and of data variability are discussed. Choices that can affect the determination of sensory shelf life of coffee are considered.
Source : LWT-Food-Science-and Technology 2008 vol.41 (10), pp 2070-2078
Koshino, L. L.; Gomes, C. P.; Silva, L. P.; Eira, M.-T. S.; Bloch, C., Jr.; Franco, O. L.; Mehta, A.
During coffee seed development, proteins are predominantly deposited in cotyledons and in the endosperm. Reserve proteins of the 11S family are the most abundant globulins in coffee seeds, acting as an N source during roasting and guaranteeing flavour and aroma. Protein profiles of endosperm and zygotic embryos of coffee seeds were compared. Proteins were extracted from whole seeds as well as from embryos and endosperm, separately. Total proteins were analysed by 2-D electrophoresis (2-DE) followed by identification by MS. The most abundant spots observed in the gels of coffee seeds were excised, digested with trypsin, and identified by MS as subunits of the 11S globulin. Spots with identical pI and molecular masses were also observed in the protein profiles of coffee endosperm and embryos, indicating that 11S protein is also highly expressed in those tissues. Peptide sequence coverage of about 20% of the entire 11S globulin was obtained. 3 other proteins were identified in embryo and endosperm 2-DE profiles as a Cupin superfamily protein, an allergenic protein (Pru ar 1), exclusive to the endosperm 2D map, and a hypothetical protein, observed only in the zygotic embryo profile.
Source : J Agric Food Chem 2008 vol.56 (22), pp 10922 - 10926