Ribeiro-Dias, D.; Marques-Vilela, D.; Pinto-Coelho-Silvestre, M.; Freitas-Schwan, R.
Two strains of Bacillus, one from a culture collection (Bacillus subtilis ATCC 6633) and a wild type (Bacillus sp. UFLA 817CF) isolated from coffee beans during their fermentation were evaluated in relation to their secretion of alkaline proteinases. The strains were grown on nutrient broth alone or with addition of sodium caseinate or cheese whey powder (0.01, 0.1 or 1.0% w/v) for 72 h. Samples were collected at 24-h intervals to evaluate proteolytic activity, protein content and cell population. Max. proteinase activity was observed after 24-h of growth for both strains, a period that coincided with the end of the exponential phase. Max. specific activities were, respectively, 839.8 U/mg for B. subtilis ATCC 6633 and 975.9 U/mg for Bacillus sp. UFLA 817CF. For all cultures of strain UFLA 817CF established, the fraction of the culture filtrate obtained via precipitation using 60% ammonium sulfate (40, 60 and 80% were applied) contained the highest specific proteinase activity. Furthermore, Bacillus sp. UFLA 817CF produced the highest enzymic activity at pH 9.0 and 40°C in the media tested (pH values of 3-11 and temp. of 30-70°C were tested). The proteinase activity secreted by the wild Bacillus strain was stable at pH 7.0 and showed considerable heat stability at 40 and 50°C, therefore, it is suggested that, it could be used industrially to utilize cheese whey for production of proteolytic enzymes.
Source : World J Microbiol Biotechnol 2008 vol.24 (10), pp 2027 - 2034
Noonim, P.; Mahakarnchanakul, W.; Nielsen, K. F.; Frisvad, J. C.; Samson, R. A.
In 2006 and 2007, 32 Thai dried coffee bean samples (Coffea arabica) from two growing sites of Chiang Mai Province, and 32 Thai dried coffee bean samples (Coffea canephora var. robusta) from two growing sites of Chumphon Province, Thailand, were collected and assessed for the distribution of fungi with the potential to produce ochratoxin A (OTA). The overall percentage of fungal contamination in coffee was 98% and reduced to 60% after surface disinfection. There were remarkable ecological differences in the composition of ochratoxigenic species present in these two regions. Arabica coffee bean samples from the North had an average of 78% incidence of colonization with Aspergillus of section Circumdati with Aspergillus westerdijkiae and A. melleus as the predominant species. Aspergillus spp. of section Nigri were found in 75% of the samples whereas A. ochraceus was not detected. Robusta coffee beans from the South were 98-100% contaminated with predominantly A. carbonarius and A. niger. A. westerdijkiae was only found in one sample. The diversity of the fungal population was probably correlated with the geographical origin of the coffee, coffee cultivar, and processing method. Representative isolates of section Circumdati (52) and Nigri (82) were examined for their OTA production using HPLC with fluorescence detection. Aspergillus westerdijkiae (42 isolates out of 42), A. steynii (13/13), and A. carbonarius (35/35) in general produced large amounts of OTA, while one isolate of A. sclerotiorum produced intermediate amounts of OTA. 13% of the A. niger isolates produced OTA in intermediate amounts. OTA levels in coffee bean samples were analyzed using the Ridascreen(R) OTA ELISA kits. Of the 64 coffee bean samples analyzed, 98% were contaminated with OTA in levels of <0.6-5.5 mug/kg (Arabica) and 1-27 mug/kg (Robusta). Presence of OTA in representative coffee samples was also confirmed by LC-MS/MS after ion-exchange purification.
Source : Intern J Food Microbiol 2008 vol. 128 (2), pp 197 - 202
Kamal, I. M.; Sobolik, V.; Kristiawan, M.; Mounir, S. M.; Allaf, K.
The Instantaneous Controlled Pressure Drop (DIC) process can be used to expand the structure of green coffee beans and improve their quality characteristics. This study investigated the effects of two DIC processes, based on steam or microwave heating, on the structure expansion ratio of Ethiopian or Brazilian coffee beans. Response surface methodology was used to determine the optimum conditions of pressure, heating time and initial moisture content. It was demonstrated that both systems expanded the structure and increased the hydration capacity of raw coffee beans; however, steam DIC had a greater effect on expansion than did microwave DIC. The expansion of Brazilian beans was also greater than that of Ethiopian beans.
Source : Innov Food Sci Emerg Technol 2008 vol.9 (4), pp 534-541
Bezerra, J. P.; da Silva, L. R.; Alvarenga-Lemos, V. A.; Duarte, P. M.; Bastos, M. F.
Although some studies have reported a negative influence of caffeine on bone metabolism, there is no information about its effect on the progression of periodontitis. The aim of this study was to evaluate the effect of high doses of caffeine on ligature-induced periodontitis in rats. Methods: Twenty-two Wistar rats were assigned to one of the following groups: non-caffeine group (n = 12) = animals without caffeine ingestion; caffeine group (n = 10) = animals ingesting 10 mg/100 g body weight/day of caffeine via drinking water for 56 days. Two weeks after the beginning of caffeine intake, one of the mandibular molar was randomly assigned to receive a ligature, whereas the contralateral molar was left unligated. Forty-two days later, the animals were sacrificed, and the specimens were processed to obtain decalcified sections. The area of periodontal ligament and/or bone loss in the furcation region of the first molars was histometrically determined. Results: Caffeine intake did not have a direct effect on the alveolar bone loss in unligated teeth. But on the ligated tooth, a greater area of bone loss was observed in the animals that ingested caffeine compared to those that did not (P <0.05). Conclusion: The present study demonstrated that daily intake of high doses of caffeine may enhance ligature-induced periodontitis progression.
Greenberg, J. A.; Chow, G.; Ziegelstein, R. C.
The relation between caffeinated coffee consumption and heart disease morbidity and mortality is of great interest given the extensive use of this beverage. A recent prospective epidemiologic study found a strong protective association in elderly subjects without moderate to severe hypertension in the NHANES. To test this association in the Framingham Heart Study population, in which cardiovascular risk factors and health behaviors were carefully documented, Cox regression analyses were conducted for 1,354 subjects aged 65.4 to 96.6 years at study entry. There were 210 deaths from cardiovascular disease and 118 from coronary heart disease (CHD) during 10.1 years of follow-up. A significant negative association between caffeinated coffee consumption and CHD mortality was observed for subjects with systolic blood pressure (BP) <160 mm Hg and diastolic BP <100 mm Hg. The decrease in risk of CHD mortality for any caffeinated coffee versus none was 43% (95% confidence interval 9 to 64). This decreased risk appeared to be caused primarily by an inverse prospective relation between caffeinated coffee consumption and the development or progression of heart valve disease. The decrease in risk of heart valve disease for subjects with systolic BP <160 mm Hg and diastolic BP <100 mm Hg for any caffeinated coffee versus none was 43% (95% confidence interval 4 to 66). In conclusion, caffeinated coffee consumption was associated with lower risk of CHD mortality and heart valve disease development or progression in older Framingham subjects without moderate or severe hypertension.
Charles, B. G.; Townsend, S. R.; Steer, P. A.; Flenady, V. J.; Gray, P. H.; Shearman, A.
The objective of this study was to develop a population model of the pharmacokinetics (PK) of caffeine after orogastric or intravenous administration to extremely premature neonates with apnea of prematurity who were to undergo extubation from ventilation. Infants of gestational age <30 weeks were randomly allocated to receive maintenance caffeine citrate dosing of either 5 or 20 mg/kg/d. Four blood samples were drawn at prerandomized times from each infant during caffeine treatment. Serum caffeine was assayed by enzyme-multiplied immunoassay technique. Concentration data (431 samples, median: 4 per subject) were obtained from 110 (52 male) infants of mean birth weight of 1009 g, current mean weight (WT) of 992 g, mean gestational age of 27.6 weeks, and mean postnatal age (PNA) of 12 days. Of 1022 doses given, 145 were orogastric, permitting estimation of absolute bioavailability. A 1-compartment model with first-order absorption was fitted to the data in NONMEM. Patient characteristics were screened (P < 0.01) in nested models for pharmacokinetic influence. Model stability was assessed by nonparametric bootstrapping. Clearance (CL) increased nonlinearly with increasing PNA, whereas volume of distribution (Vd) increased linearly with WT, according to the following allometric models: CL (L/h) = 0.167 (WT/70) (PNA/12); Vd (L) = 58.7 (WT/70). The mean elimination half-life was 101. Interindividual variability (IIV) of CL and Vd was 18.8 % and 22.3 %, respectively. Interoccasion variability (IOV) of CL and Vd was 35.1% and 11.1%, respectively. This study established that the elimination of caffeine was severely depressed in extremely premature infants but increased nonlinearly after birth up to age 6 weeks. Caffeine was completely absorbed, which has favorable implications for switching between intravenous and orogastric routes. The interoccasion variability about CL was twice the interindividual variability, which, among other factors, indicates that routine serum concentration monitoring of caffeine in these patients is not warranted.
Farah, A.; Monteiro, M.; Donangelo, C. M.; Lafay, S.
Chlorogenic acids (CGA) are cinnamic acid derivatives with biological effects mostly related to their antioxidant and antiinflammatory activities. Caffeoylquinic acids (CQA) and dicaffeoylquinic acids (diCQA) are the main CGA found in nature. Because green coffee is a major source of CGA, it has been used for production of nutraceuticals. However, data on the bioavailability of CGA from green coffee in humans are inexistent. The present study evaluated the pharmacokinetic profile and apparent bioavailability of CGA in plasma and urine of 10 healthy adults for 8 h after the consumption of a decaffeinated green coffee extract containing 170 mg of CGA. Three CQA, 3 diCQA, and caffeic, ferulic, isoferulic, and p-coumaric acids were identified in plasma by HPLC-Diode Array Detector-MS after treatment. Over 30% (33.1 +/- 23.1%) of the ingested cinnamic acid moieties were recovered in plasma, including metabolites, with peak levels from 0.5 to 8 h after treatment. CGA and metabolites identified in urine after treatment were 4-CQA, 5-CQA, and sinapic, p-hydroxybenzoic, gallic, vanillic, dihydrocaffeic, caffeic, ferulic, isoferulic, and p-coumaric acids, totaling 5.5 +/- 10.6% urinary recovery of the ingested cinnamic and quinic acid moiteties. This study shows that the major CGA compounds present in green coffee are highly absorbed and metabolized in humans.
Naganuma, T.; Kuriyama, S.; Kakizaki, M.; Sone, T.; Nakaya, N.; Ohmori-Matsuda, K.; Nishino, Y.; Fukao, A.; Tsuji, I.
An inverse association between coffee consumption and the risk of oral, pharyngeal, and esophageal cancers has been suggested in case-control studies, but few results from prospective studies are available. Data from the Miyagi Cohort Study in Japan were used to clarify the association between coffee consumption and the risk of these cancers. Information about coffee consumption was obtained from self-administered food frequency questionnaires in 1990. Among 38,679 subjects aged 40-64 years with no previous history of cancer, 157 cases of oral, pharyngeal, and esophageal cancers were identified during 13.6 years of follow-up. Hazard ratios were estimated by the Cox proportional hazards regression model. The risk of oral, pharyngeal, and esophageal cancers was inversely associated with coffee consumption. The multivariate-adjusted hazard ratio of these cancers for >/=1 cups of coffee per day compared with no consumption was 0.51 (95% confidence interval: 0.33, 0.77). This inverse association was consistent regardless of sex and cancer site and was observed both for subjects who did not drink or smoke and for those who currently drank or smoked at baseline. In conclusion, coffee consumption was associated with a lower risk of oral, pharyngeal, and esophageal cancers, even in the group at high risk of these cancers.
Linnet, K. M.; Wisborg, K.; Secher, N. J.; Thomsen, P. H.; Obel, C.; Dalsgaard, S.; Henriksen, T. B.
Based on hypotheses from experimental studies, we studied the association between intrauterine exposure to coffee and the risk of clinically verified hyperkinetic disorder and attention-deficit hyperactivity disorder (ADHD). METHODS: A cohort study with prospectively collected data from the Aarhus Birth Cohort, Denmark. We included 24 068 singletons delivered between 1990 and 1998. Linkage was performed with three Danish longitudinal registers: The Danish Psychiatric Central Register, The Integrated Database for Labour Market Research and The Danish Civil Registration System. We identified 88 children with hyperkinetic disorder and ADHD. Information about coffee consumption during pregnancy was obtained at 16 weeks of gestation from self-administrated questionnaires. Potential confounding factors were evaluated using Cox regression analyses. RESULTS: We found that intrauterine exposure to 10 or more cups of coffee per day was associated with a threefold increased risk of hyperkinetic disorder and ADHD. After adjustments for a number of confounding factors, the risk decreased and became statistically insignificant (RR 2.3, 95% CI 0.9-5.9). CONCLUSION: Prenatal exposure to high levels of coffee did not significantly increase the risk of clinically verified hyperkinetic disorder and ADHD in childhood.
Natella, F.; Nardini, M.; Belelli, F.; Pignatelli, P.; Santo, S. di; Ghiselli, A.; Violi, F.; Scaccini, C.
Epidemiological studies indicate a J-shaped relationship linking coffee consumption and cardiovascular risk, suggesting that moderate coffee consumption can be beneficial. Platelet aggregation is of critical importance in thrombotic events, and platelets play a major role in the aetiology of several CVD. The aim of this study was to evaluate the effect of coffee drinking on platelet aggregation ex vivo, using caffeine as control. A crossover study was performed on 10 healthy subjects. In 2 different sessions, subjects drank 200 ml coffee, containing 180 mg caffeine, or a capsule of caffeine (180 mg) with 200 ml water. Platelets were separated from plasma at baseline and 30 and 60 min after coffee drinking. Platelet aggregation was induced with 3 different agonists: collagen, arachidonic acid and ADP. Coffee drinking inhibited collagen (P < 0.05 from baseline at time 30 min) and arachidonic acid (P < 0.05 from baseline at time 60 min) induced platelet aggregation. Caffeine intake did not affect platelet aggregation induced by the 3 agonists. Coffee consumption induced a significant increase of platelet phenolic acids (likely present as glucuronate and sulphate derivatives), caffeic acid, the principal phenolic acid in coffee, raising from 0.3 (s.e. of the mean (sem) 0.1) to 2.4 (sem 0.6) ng/mg (P < 0.01). Caffeine was not detectable in platelets. These findings indicate that coffee drinking decreases platelet aggregation, and induces a significant increase in phenolic acid platelet concn. The antiplatelet effect of coffee is independent from caffeine and could be a result of the interaction of coffee phenolic acids with the intracellular signalling network leading to platelet aggregation.
Source : Intern J Food Microbiol 2008 vol. 128 (2), pp 197 - 202
Keane, M. A.; James, J. E.
Until recently, little account had been taken of the confounding effects of caffeine withdrawal and withdrawal reversal when examining the net effects of dietary caffeine. OBJECTIVES: By including a manipulation involving sleep restriction, the present study aimed to extend recent findings from research in which caffeine withdrawal and withdrawal reversal were controlled. The main aims of the study were to examine the net effects of caffeine, as well as its potential restorative effects following sleep restriction, on EEG, performance and mood. METHOD: A randomised cross-over design was used in which 15 participants alternated weekly between ingesting placebo and caffeine (1.75 mg/kg) three times daily for four consecutive weeks following either usual sleep or sleep restriction. EEG activity was measured at 32 sites during eyes closed, eyes open and performance of a vigilance task. RESULTS: Modest effects of caffeine were found in the delta and beta bandwidths, but no main effects of caffeine were observed in the theta or alpha bandwidths. Overall, the effects of caffeine on EEG activity were relatively few, weak and inconsistent, and no evidence was found of net restorative effects of caffeine for any outcome variables.
CONCLUSIONS: The findings do not support the use of caffeine as a means for enhancing human function or as an antidote to the negative effects of sleep loss.
Ferraz, G. C.; Teixeira-Neto, A. R.; Mataqueiro, M. I.; Lacerda-Neto, J. C.; Queiroz-Neto, A.
Objective:To investigate the effect of acute administration of caffeine on the athletic performance of Arabian horses. Animals-12 healthy adult Arabian horses that were trained for exercise on a treadmill. Procedures-By use of a crossover study design, horses received each of the following treatments: IV administration of caffeine (5 mg/kg) and IV administration of approximately the same volume of saline (0.9% NaCl) solution. Order of treatment was randomized, and there was a 10-day interval between treatments. Thirty minutes after treatments, horses underwent an incremental exercise test (IET) on a treadmill. Blood samples were collected 15 seconds before the end of each velocity step of the IET for determination of blood lactate, blood glucose, plasma cortisol, and plasma insulin concentrations. Heart rate and hematologic variables were also analyzed. Results-Velocities achieved when heart rates were 180 and 200 beats/min increased significantly in caffeine-treated horses, compared with control horses. Velocities corresponding to blood lactate concentrations of 4 and 2 mmol/L decreased significantly in caffeine-treated horses, compared with control horses. In comparison between groups, insulinemia was greater in control horses and glycemia was greater in caffeine-treated horses. Plasma cortisol concentration was significantly lowered by treatment with caffeine.
Conclusions and Clinical Relevance-IV administration of caffeine at 5 mg/kg improved the performance of Arabian horses during intense exercise of short duration and diminished the oxidative metabolism of glucose.
Reyes, E.; Loong, C. Y.; Harbinson, M.; Donovan, J.; Anagnostopoulos, C.; Underwood, S. R.
We studied whether an increase in adenosine dose overcomes caffeine antagonism on adenosine-mediated coronary vasodilation. BACKGROUND: Caffeine is a competitive antagonist at the adenosine receptors, but it is unclear whether caffeine in coffee alters the actions of exogenous adenosine, and whether the antagonism can be surmounted by increasing the adenosine dose. METHODS: Myocardial perfusion scintigraphy (../../../MPS.jpg) was used to assess adenosine-induced hyperemia in 30 patients before (baseline) and after coffee ingestion (caffeine). At baseline, patients received 140 microg/kg/min of adenosine combined with low-level exercise. For the caffeine study, 12 patients received 140 microg/kg/min of adenosine (standard) and 18 patients received 210 microg/kg/min (high dose) after caffeine intake (200 mg). Myocardial perfusion was assessed semiquantitatively and quantitatively, and perfusion defect was characterized according to the presence of reversibility. RESULTS: Caffeine reduced the magnitude of perfusion abnormality induced by standard adenosine as measured by the summed difference score (SDS) (12.0 +/- 4.4 at baseline vs. 4.1 +/- 2.1 after caffeine, p < 0.001) as well as defect size (18% [3% to 38%] vs. 8% [0% to 22%], p < 0.01), whereas it had no effect on the abnormalities caused by high-dose adenosine (SDS, 7.7 +/- 4.0 at baseline vs. 7.8 +/- 4.2 after caffeine, p = 0.7). There was good agreement between baseline and caffeine studies for segmental defect category (kappa = 0.72, 95% confidence interval: 0.65 to 0.79) in the high-dose group. An increase in adenosine after caffeine intake was well tolerated.
CONCLUSIONS: Caffeine in coffee attenuates adenosine-induced coronary hyperemia and, consequently, the detection of perfusion abnormality by adenosine ../../../MPS.jpg. This can be overcome by increasing the adenosine dose without compromising test tolerability.
Yamaguchi, T.; Chikama, A.; Mori, K.; Watanabe, T.; Shioya, Y.; Katsuragi, Y.; Tokimitsu, I.
Metabolites of chlorogenic acids (CGA) found in coffee may exhibit antihypertensive activity; however, data examining the impact of coffee on blood pressure (BP) are inconsistent. It has been suggested that the antihypertensive activity of CGA may be inhibited by hydroxyhydroquinone (HHQ) which is produced when green coffee beans are roasted. In this study, a double-blind, randomized, controlled, dose-response trial was undertaken to examine the impact of CGA in HHQ-free coffee on BP. The study included 203 mildly hypertensive men and women in 5 groups including control, zero-, low-, middle- and high-dose, in which the control beverage was identical to ordinary coffee and the other coffee beverages contained adjusted CGA levels and reduced HHQ levels compared to ordinary coffee. Following a baseline 6 wk observation period, the participants consumed 1 cup of coffee per day for 4 wk. Results indicated that CGA shows antihypertensive activity in a dose-dependent manner when consumed in HHQ-free coffee but the ordinary coffee exhibits almost no effect. A significant correlation was noted between BP change and the 3 dose-response patterns (P < 0.001). It is concluded that CGA in HHQ-free coffee exhibits dose-dependent antihypertensive activity.
Hsu, T. L.; Bau, J. G.; Wang, W. K.; Li, S. P.; Wang, Y. Y.
Previously, we found that qi-stimulating events exerted similar frequency-specific effects on the blood pressure pulse spectrum. Because coffee and qi induce similar stimulatory psychological responses, we aimed to determine whether they would induce similar pulse effects. Such a relationship would suggest a close linkage between the physiologic mechanisms underlying the psychostimulatory responses and vascular effects of coffee and qi. Therefore, the profound investigations into the mechanisms underlying the effects of coffee on the central nervous system and the vascular system may help to elucidate the underlying physiology mechanisms of qi. METHODS: Each test subject took three rounds of 150 mL coffee (0.1 g/kg, 0.05 g/kg, 0.05 g/kg) in a 30-minute interval. The subject\'s pulses were recorded at the end of each round. The changes in the test subject\'s pulse spectrum between before and after coffee consumption were compared with changes induced by a water placebo. RESULTS: Both coffee and qi caused the intensities of the third, sixth, and ninth harmonics of the pressure pulse spectrum to be relative peaks to their neighboring harmonics.
CONCLUSION: Our results suggest that the coffee effect may be considered a qi-stimulating event, and there is a common physiologic factor determining the psychostimulatory responses of qi and coffee as well as their effects on the cardiovascular system, which results in a specific frequency pattern in the blood pulse spectrum. Adenosine, which is the main physiologic compound affected by coffee, might also be the key factor affected by qi.
Source : J Altern Complement Med 2008 vol. 14 (9), pp 1145 - 1150
Hulston, C. J.; Jeukendrup, A. E.
PURPOSE: 1) To investigate the effect of caffeine on exogenous carbohydrate (CHO) oxidation and glucose kinetics during exercise; and 2) to determine whether combined ingestion of caffeine and CHO enhanced cycling performance compared with CHO alone. METHODS:: Ten endurance-trained cyclists performed three experimental trials consisting of 105 min steady-state (SS) cycling at 62% V(dot)dot;O2max followed by a time trial (TT) lasting approximately 45 min. During exercise, subjects ingested either of the following: a 6.4% glucose solution (GLU), a 6.4% glucose plus caffeine solution providing 5.3 mg.kg of caffeine (GLU + CAF), or a placebo (PLA). Glucose solutions contained a trace amount of [U-C]glucose, and eight subjects received a primed continuous [6,6-H2]glucose infusion. RESULTS:: Peak exogenous CHO oxidation rates were not significantly different between GLU and GLU + CAF trials (52.6 +/- 2.7 and 49.1 +/- 2.1 mumol.kg.min, respectively). Rates of appearance (Ra) and disappearance (Rd) of glucose were significantly higher with CHO ingestion than PLA (P < 0.01) but were not significantly different between GLU and GLU + CAF trials. Performance times were 43.45 +/- 0.86, 45.45 +/- 1.07, and 47.40 +/- 1.30 min for GLU + CAF, GLU, and PLA, respectively. Therefore, GLU + CAF ingestion enhanced TT performance by 4.6% (P < 0.05) compared with GLU and 9% (P < 0.05) compared with PLA.
CONCLUSION: The coingestion of caffeine (5.3 mg.kg) with CHO during exercise enhanced TT performance by 4.6% compared with CHO and 9.0% compared with water placebo. However, caffeine did not influence exogenous CHO oxidation or glucose kinetics during SS exercise.
Source : Med Sci Sports Exerc 2008 vol.40 (12), pp 2096 - 2104
Tao, K. S.; Wang, W.; Wang, L.; Cao, D. Y.; Li, Y. Q.; Wu, S. X.; Dou, K. F.
Epidemiological studies have found an inverse association between coffee consumption and the risk of liver cancer. Animal data support such a chemopreventive effect of coffee. Substantial research has been devoted to the identification of coffee components that may be responsible for these beneficial effects. Based on the current available literature, three major components, i.e. coffee diterpenes cafestol and kahweol (C+K), caffeine and chlorogenic acid contribute to the beneficial effects. These components induce phase II detoxifying and antioxidant enzymes as well as inhibit the expression or decrease the activity of phase I activating enzymes thus prevent carcinogenesis. These components target different stages of a common pathway, Kelch-like ECH-associated protein 1 (Keap1) - NF-E2-related factor-2 (Nrf2) -antioxidant-responsive-element (ARE) signal pathway thus alter the ARE-dependent expression of genes needed in the anti-tumorigenic effects.
Manzocco, L.; Lagazio, C.
A methodology for the development of shelf life models predicting consumer acceptability of coffee brew on the basis of simple and easily detectable quality indices was proposed. Coffee brew was assessed during storage for consumer acceptability using both acceptability scoring methodology and evaluation of consumer rejection by survival analysis. Samples were also analysed for hydrogen ion concentration and intensity of sensory attributes (acid, off-flavour and bitter) by a trained sensory panel. Hydrogen ion
concentration and sourness resulted to be the indices best correlating with the percentage of consumer rejecting the product during storage. Mathematical functions predicting hydrogen ion concentration and sourness as a function of the risk of consumer rejection were defined. These equations provided information to assist companies in choosing acceptance limits and were integrated with classic shelf life kinetic approach to produce shelf life models accounting for consumer response. Due to lower uncertainty of hydrogen ion concentration data as compared to sourness sensory data, only the former resulted to be a useful indicator of coffee brew shelf life.
Source : Food Quality and Preference 2009 vol.20 (1), pp 24 - 29
Perez-Martinez, M.; Sopelana, P.; Pena, M.-P. de; Cid, C.
Changes in both the composition and in some sensory parameters of Colombian Arabica coffee brews stored at room and refrigeration temp., with and without O2, were monitored. Some nonvolatile compounds related to the flavour of coffee brews were determined, in an attempt to study possible relationships between chemical and sensory changes. Storage time hardly affected the amounts of chlorogenic, caffeic and ferulic acids, which are reported to have some beneficial health effects, mainly due to their antioxidant activities. In contrast, pH decreased in all the coffee brews with time, mainly in that stored at 25°C with O2. The appearance of sourness and other non typical coffee tastes (rancid taste, aftertaste) and an increase in astringency led to establishment of a shelf-life of 10 days for coffee brews stored at 25°C with O2, 15 days for coffee brews stored at 4°C with O2 and at 25°C without O2, and 20 days for coffee brews stored at 4°C without O2. The behaviour of 5-caffeoylquinic acid, caffeic acid and 4-vinylguaiacol throughout time was different from that observed in other studies conducted at higher temp. to accelerate the staling, which reveals that stability studies of coffee brews should be conducted at real time and temp.
Source : Eur Food Res Technol 2008 vol.227 (6), pp 1633 - 1640
Su, Jin Park; Sang, Do Yeo
Recrystallization of caffeine from solutions in chloroform and methylene chloride at concn. of 0.15 and 0.083 g/ml, respectively, was investigated using CO2 as an antisolvent. Injection of CO2 into these solutions induced supersaturation and particle precipitation. Effects of crystallization temp., solvent type and CO2 injection rate were investigated on the solid-state properties of the extracted caffeine samples. Effects of a growth retardant on crystal habit and particle size were also determined. The recrystallized caffeine particles consistently demonstrated acicular crystal properties. Higher temp. led to smaller crystals, and use of the growth retardant, alpha-D-glucose penta-acetate resulted in sub-micron sized crystals. More orderly arrangements of caffeine molecules were obtained at lower crystallization temp. It is suggested that addition of a growth retardant may have suppressed the ordered growth in some minor directions, causing the molecules to arrange themselves in a particular orientation.
Cristancho, M.; Escobar, C.
The aim of the present research was to test the transferability of simple sequence repeat (SSR) markers developed in two Uredinales species to Hemileia vastatrix, coffee rust. The development of efficient techniques for the identification of H. vastatrix isolates is imperative, given the continuous development of new races. The transferability of 25 SSR markers developed in the related Uredinales species Puccinia coronata f. sp lolli and Mela../../../MPS.jpgora linii to H. vastatrix was tested. A low level of transferability of SSRs was detected, and only 4 potential markers that can be used to fingerprint the coffee rust races were identified.
Source : Genet Mol Res 2008 vol1 (4), pp 1186 - 1192 (full text)