Melo, G. A.; Shimizu, M. M.; Mazzafera, P.
In plants, PPO has been related to defense mechanism against pathogens and insects and this role was investigated in coffee trees regarding resistance against a leaf miner and coffee leaf rust disease. PPO activity was evaluated in different genotypes and in relation to methyl-jasmonate (Meja) treatment and mechanical damage. Evaluations were also performed using compatible and incompatible interactions of coffee with the fungus Hemileia vastatrix (causal agent of the leaf orange rust disease) and the insect Leucoptera coffeella (coffee leaf miner). The constitutive level of PPO activity observed for the 15 genotypes ranged from 3.8 to 88 units of activity/mg protein. However, no direct relationship was found with resistance of coffee to the fungus or insect. Chlorogenic acid (5-caffeoylquinic acid), the best substrate for coffee leaf PPO, was not related to resistance, suggesting that oxidation of other phenolics by PPO might play a role, as indicated by HPLC profiles. Mechanical damage, Meja treatment, H. vastatrix fungus inoculation and L. coffeella infestation caused different responses in PPO activity. These results suggest that coffee resistance may be related to the oxidative potential of the tissue regarding the phenolic composition rather than simply to a higher PPO activity.
Vaast, P.; Bertrand, B.; Perrio, J. J.; Guyot, B.; Genard, M.
Influence of shading and thinning on coffee production patterns, coffee bean composition and sensory properties of coffee beverages was studied. Coffee trees of the dwarf cv. Costa Rica 95 (full fruit load or manually thinned to quarter or half fruit loads) were cultivated in full sun or 45% shade over 2 production cycles. Harvested coffee berries were analysed for size characteristics and contents of caffeine, fat, sucrose, chlorogenic acids and trigonelline. Quality of coffee infusions was assessed by a sensory panel in terms of acidity, bitterness, astringency and body. Cultivation in shaded conditions delayed berry ripening and had a beneficial influence on coffee bean size and composition (including increased caffeine content) as well as beverage sensory properties. Berries cultivated in full sun demonstrated incomplete ripening resulting in increased sucrose, chlorogenic acid and trigonelline contents in coffee beans and coffee beverages with higher bitterness and astringency.
Avelino, J.; Barboza, B.; Araya, J. C.; Fonseca, C.; Davrieux, F.; Guyot, B.; Cilas, C.
This study of the effects of environmental factors on the quality of coffees from two altitude terroirs of Costa Rica (Orosi: 1,020-1,250 m; and Santa Maria de Dota: 1,550-1,780 m), found east-facing slopes to give superior (more acidic) coffee, probably as a result of greater exposure to morning sunlight. Within terroirs, higher altitudes gave superior coffee. At Santa Maria de Dota, where some trees produced up to 13 kg of coffee cherries, yield was inversely related to acidity. Overall, coffees from Orosi had a floral flavour, which depended on slope exposure, while coffees from Santa Maria de Dota had a chocolate taste, which increased at high altitude.
Gouveia, M. M.; Ribeiro, A.; Varzea, V. M.; Rodrigues, C.-J. Jr
Random amplified polymorphic DNA (RAPD) was used to assess the genetic structure of Hemileia vastatrix populations. Forty-five rust isolates with different virulence spectra and from different hosts and geographical regions were analyzed. Out of 45 bands, generated with three RAPD primers, 35 (78%) were polymorphic and scored as molecular markers. Cluster analysis exhibits unstructured variability of this pathogen with regard to physiological race, geographical origin or host. The genotypic diversity (H') inferred from Shannon's index was higher than gene diversity (Ht), suggesting that diversity is distributed among clonal lineages. Estimates of gene diversity in Africa and Asia populations were higher in total (Ht) as compared to within population diversity (Hs). Genetic differentiation was considerable among coffee rust isolates from Africa (Gst = 0.865) and Asia (Gst = 0.768) but not among isolates from South America (Gst = 0.266). We concluded that genetic diversity in H. vastatrix was moderately low and that the genetic differentiation among populations shows that asexual reproduction is likely to play an important role in the population biology of this fungus. This should be taken into account for the development of breeding programs.
Source : Mycologia, vol. 97 (2), pp 396 - 404
Lin, C.; Mueller, L. A.; Mc-Carthy, J.; Crouzillat, D.; Petiard, V.; Tanksley, S. D.
An EST database has been generated for coffee based on sequences from approximately 47,000 cDNA clones derived from five different stages/tissues, with a special focus on developing seeds. When computationally assembled, these sequences correspond to 13,175 unigenes, which were analyzed with respect to functional annotation, expression profile and evolution. Compared with Arabidopsis, the coffee unigenes encode a higher proportion of proteins related to protein modification/turnover and metabolism-an observation that may explain the high diversity of metabolites found in coffee and related species. Several gene families were found to be either expanded or unique to coffee when compared with Arabidopsis. A high proportion of these families encode proteins assigned to functions related to disease resistance. Such families may have expanded and evolved rapidly under the intense pathogen pressure experienced by a tropical, perennial species like coffee. Finally, the coffee gene repertoire was compared with that of Arabidopsis and Solanaceous species (e.g. tomato). Unlike Arabidopsis, tomato has a nearly perfect gene-for-gene match with coffee. These results are consistent with the facts that coffee and tomato have a similar genome size, chromosome karyotype (tomato, n=12; coffee n=11) and chromosome architecture. Moreover, both belong to the Asterid I clade of dicot plant families. Thus, the biology of coffee (family Rubiacaeae) and tomato (family Solanaceae) may be united into one common network of shared discoveries, resources and information.
Kawasaki, N.; Kinoshita, H.; Oue, T.; Nakamura, T.; Tanada, S.
Coffee grounds are a vegetable biomass that are often disposed of by burning; however, the carbon dioxide generated by burning coffee grounds is affecting global warming. In this study, the possibility of using carbonaceous by-products produced from coffee grounds for ammonia elimination was investigated and compared to activated C made from steam-activated coconut shells. Carbonaceous materials were prepared by microwave treatment of the coffee grounds. Saturated amounts of ammonia adsorbed by some of the carbonaceous materials produced from coffee grounds were greater than those adsorbed by activated C. In contrast, the activated C adsorption rate for ammonia was higher than those of the carbonaceous materials. Results indicated that the carbonaceous materials produced from coffee grounds could be utilized for the removal of ammonia in the gaseous phase.
Farah, A.; Paulis, T. de; Moreira, D. P.; Trugo, L. C.; Martin, P. R.
The market for decaffeinated coffees has been expanding. However, caffeine extraction may result in the loss of other compounds such as chlorogenic acids (CGA) and, consequently, their 1,5-gamma-quinolactones (CGL) in roasted coffee. These phenols are important for flavour formation as well as the beneficial health effects of coffee; therefore, losses due to decaffeination require study. The impact of the decaffeination process on CGA and CGL levels of green and roasted arabica coffees was evaluated. Decaffeination produced on average a 16% increase in levels of total CGA in green coffee (DM), along with a 237% increase in CGL direct precursors. Different degrees of roasting showed average increments of 5.5-18% in CGL levels of decaffeinated coffee, compared to regular, a change more consistent with observed levels of total CGA than with those of CGL direct precursors in green samples. However, CGA levels in roasted coffee were 3-9% lower in decaffeinated coffee compared to regular coffee. Although differences in CGA and CGL contents of regular and decaffeinated roasted coffees appear to be relatively small, they may be enough to affect flavour characteristics as well as the biopharmacological properties of the final beverage.
Redgwell, R. J.; Fischer, M.; Curti, D.; Sutherland, P.; Hallett, I.; MacRae, E.
Arabinogalactan-proteins (AGPs) are present in the cell walls of several varieties of Robusta and Arabica coffees. This reviews discusses the current knowledge of coffee bean AGPs in relation to chemical features and spatial location across the wall; changes induced by the roasting process; and physicochemical properties that support the possibility of green coffee beans being used as a source of hydrocolloid. Coffee AGPs may be useful as functional hydrocolloids where surface active hydrocolloids with relatively low viscosity may be required.
Source : Foods and Food Ingredients Journal of Japan, 2006 vol. 211 (1), 38-47
Marraccini, P.; Rogers, W. J.; Caillet, V.; Deshayes, A.; Granato, D.; Lausanne, F.; Lechat, S.; Pridmore, D.; Petiard, V.
Alpha-D-Galactosidase (alpha-Gal; EC 3.2.1.22) is one of three principal enzymes involved in the modification or degradation of plant cell wall galactomannans. In the present paper it is shown that alpha-galactosidase activities in field-grown coffee beans are variable amongst cultivars of the two species investigated (Coffea arabica and C. canephora var. Robusta). Higher activities were found in Arabica cultivars. Using beans from greenhouse-cultivated C. arabica as a model, we showed that alpha-Gal activity was undetectable in the bean perispem tissue, but increased gradually during the endosperm development, to reach a peak at approximately 30 weeks after flowering (WAF) which coincided with the hardening of the endosperm. Alpha-Gal-specific transcripts detected at 22 and 27 WAF accompanied the peak of alpha-Gal activity, but were reduced to be undetectable in mature beans at 30 WAF, while alpha-Gal activity still persisted. Two isoforms were distinguished in 2-DE profiles of crude protein extracts by N-terminal sequencing analysis. Analysis of two-dimensional gel electrophoresis profiles demonstrated that both isoforms accumulated in a linear fashion throughout grain maturation. Alpha-Gal activity was also observed to increase to high levels during in vitro germination of coffee beans suggesting an important function of this enzyme in this process. Alpha-Gal cDNA sequences from Arabica and Robusta were sequenced and their deduced proteins appeared to be very similar, differing by only eight amino acids. Southern-blot analysis suggests that the enzyme was encoded by at least two genes in C. arabica that could explain the existence of the two isoforms identified in 2-DE profiles.
Source : Plant Physiol Biochem, vol. 43 (10-11), pp 909 - 920
Monteiro, M.-A. M.; Minim, V.-P. R.; Silva, A. F.; Chaves, J.-B. P.; Cardello, H.-M. A. B.
Flavour attributes of coffee (Coffea arabica) samples were investigated using time intensity analysis. The bitterness, fermented flavour and burned flavour of 9 samples of coffee (soft/light, hard/light, rio/light, soft/express, hard/express, rio/express, soft/dark, hard/dark and rio/dark) were assessed, with 6 parameters of the time intensity curve being evaluated. Samples of the dark roast had greater max. intensity and time of duration of the stimulus for bitter taste and burned flavour, while the samples of light roast exhibited lower intensity. The rio/express samples showed the greatest intensity for fermented flavour.
Source : Ciencia e Tecnologia de Alimentos, 2005 vol. 25 (4), pp 772 - 780
Larsson, S. C.; Bergkvist, L.; Giovannucci, E.; Wolk, A.
Investigators have reported an inverse association between coffee consumption and risk of colorectal cancer in several case-control studies, but prospective studies, most of them involving small numbers of cases, have not supported such a relation. In this analysis, the authors prospectively examined the association of coffee consumption with colorectal cancer risk among participants from two population-based cohort studies: 61,433 women in the Swedish Mammography Cohort and 45,306 men in the Cohort of Swedish Men. Information about coffee consumption was obtained from food frequency questionnaires in 1987-1990 and 1997 for women and in 1997 for men. The authors used Cox proportional hazards modeling for cohort-specific multivariate analyses, and results were pooled using random-effects models. During 1,240,597 person-years of follow-up, 1,279 incident cases of colorectal cancer were diagnosed. Coffee consumption was not associated with risk of colorectal cancer, colon cancer, or rectal cancer in either women or men. For both cohorts combined, the multivariate rate ratio for colorectal cancer for each additional cup of coffee per day was 1.00 (95% confidence interval: 0.97, 1.04). The associations were not modified by colorectal cancer risk factors.
CONCLUSIONS :The findings from these two large prospective cohort studies do not support the hypothesis that coffee consumption lowers the risk of colorectal cancer.
van Dam, R. M.; Willett, W. C.; Manson, J. E.; Hu, F. B.
High habitual coffee consumption has been associated with a lower risk of type 2 diabetes, but data on lower levels of consumption and on different types of coffee are sparse. RESEARCH DESIGN AND METHODS: This is a prospective cohort study including 88,259 U.S. women of the Nurses' Health Study II aged 26-46 years without history of diabetes at baseline. Consumption of coffee and other caffeine-containing foods and drinks was assessed in 1991, 1995, and 1999. We documented 1,263 incident cases of confirmed type 2 diabetes between 1991 and 2001. RESULTS: After adjustment for potential confounders, the relative risk of type 2 diabetes was 0.87 (95% CI 0.73-1.03) for one cup per day, 0.58 (0.49-0.68) for two to three cups per day, and 0.53 (0.41-0.68) for four or more cups per day compared with nondrinkers (P for trend <0.0001). Associations were similar for caffeinated (0.87 [0.83-0.91] for a one-cup increment per day) and decaffeinated (0.81 [0.73-0.90]) coffee and for filtered (0.86 [0.82-0.90]) and instant (0.83 [0.74-0.93]) coffee. Tea consumption was not substantially associated with risk of type 2 diabetes (0.88 [0.64-1.23] for four or more versus no cups per day; P for trend = 0.81).
CONCLUSIONS: These results suggest that moderate consumption of both caffeinated and decaffeinated coffee may lower risk of type 2 diabetes in younger and middle-aged women. Coffee constituents other than caffeine may affect the development of type 2 diabetes.
Source : Diabetes Care, vol. 29, pp 398 - 403
Kozuma, K.; Tsuchiya, S.; Kohori, J.; Hase, T.; Tokimitsu, I.
A water-soluble green coffee bean extract (GCE) has been shown to be effective against hypertension in both spontaneously hypertensive rats and humans. This multicenter, randomized, double-blind, placebo-controlled, parallel group study evaluated the dose-response relationship of GCE in 117 male volunteers with mild hypertension. Subjects were randomized into four groups: a placebo and three drug groups that received 46 mg, 93 mg, or 185 mg of GCE once a day. After 28 days, systolic blood pressure (SBP) in the placebo, 46 mg, 93 mg, and 185 mg groups was reduced by -1.3+/-3.0 mmHg, -3.2+/-4.6 mmHg, -4.7+/-4.5 mmHg, and -5.6+/-4.2 mmHg from the baseline, respectively. The decreases in SBP in the 93 mg group (p<0.05) and the 185 mg group (p<0.01) were statistically significant compared with the placebo group. Diastolic blood pressure (DBP) in the placebo, 46 mg, 93 mg, and 185 mg groups was reduced by -0.8+/-3.1 mmHg, -2.9+/-2.9 mmHg, -3.2+/-3.2 mmHg, and -3.9+/-2.8 mmHg from the baseline, respectively, and significant effects were observed in the 93 mg group (p<0.05) and the 185 mg group (p<0.01) compared with the placebo group. Both blood pressures were significantly reduced in a dose-related manner by GCE (p<0.001). Adverse effects caused by GCE were not observed. The results suggested that daily use of GCE has a blood pressure-lowering effect in patients with mild hypertension.
Asano, I.; Ikeda, Y.; Fujii, S.; Iino, H.
Indigestible oligosaccharides are known to improve the intestinal environment by stimulating growth of bifidobacteria and lactobacilli while inhibiting growth of pathogenic bacteria. Mannooligosaccharides (MOS) are indigestible saccharides fermented to short-chain fatty acids by human faecal bacteria. The in vivo effects of MOS obtained from coffee mannan on caecal microbiota and production of short-chain fatty acids were investigated in male Sprague-Dawley rats. Rats were fed a diet containing 5% MOS ad libitum for 28 days. The body weight of rats fed the MOS diet did not differ significantly from that of controls. MOS consumption was found to increase the concentration of bifidobacteria and the ratio of bifidobacteria to total microorganisms, while addition of dietary MOS led to a much higher concentration of short-chain fatty acids in the caecal contents compared with controls.
Source : Food-Science-and-Technology-Research, 2004 vol. 10 (3), 273-277 (not available on-line)