de Souza, M. S.; Teixeira, C. A.; Azevedo, C. O.; Costa, V. A.; Costa, J. N.
Adults of Cephalonomia stephanoderis Betrem were detected (in November 2003) during the sampling of Coffea canephora Pierre ex A. Froehner berries damaged by Hypothenemus hampei Ferrari (Coleoptera: Scolytidae) in Ouro Preto D\'Oeste - Rondonia, Brazil (10 degrees 45\'S and 62 degrees 15\'W). From January to July 2004, the parasitoid was monthly sampled in 200 berries damaged by H. hampei. Probably, C. stephanoderis can already exert some parasitism pressure at the coffee berry borer population. The occurrence of this parasitoid in natural conditions points out to another alternative for the biological control of the H. hampei in Rondonia. This is the first record of C. stephanoderis in coffee plantations of the Brazilian Amazonia.
Gopinandhan, T. N.; Keshamma, E.; Velmourougane, K.; Raghuramulu, Y.
Ochratoxin A (OTA) has been detected in commercial soluble coffees from various countries. Some of this contamination may have occurred because of adulteration of soluble coffee with coffee bean husks. In this study, OTA contamination of coffee processing solid wastes (parchment and cherry husks) was investigated. Parchment coffee (produced by wet processing of coffee and drying to a moisture content of approx. 12%) and cherry coffee (produced by dry processing of coffee fruits and drying to a moisture content of approx. 13%) samples from the 2004-2005 harvest in India were collected. Coffee samples were subjected to hulling and hand garbling to separate the green coffee beans from the husks. 40 samples comprising 10 samples each of arabica parchment, arabica cherry, robusta parchment and robusta cherry were analysed. OTA contamination in the green coffee beans after separation of the husks ranged from 0.15 to 1.56 ppb. Levels of OTA in cherry husks of robusta ranged from 1.77 to 22.3 ppb whilst those in cherry husks of arabica ranged from 3.39-19.65 ppb. Levels of OTA in robusta parchment (0.96-8.72 ppb) were similar to those in arabica parchment (1.43-6.14 ppb). Results indicate that coffee husks can be a potential source of OTA. Accordingly, it is suggested that effective separation and immediate disposal of coffee husks is of paramount importance in minimizing OTA contamination of coffee products.
Source : J Food Sci Techn 2006 vol. 43 (5), pp 488 - 490 (not available on-line)
Finzer, J.-R. D.; Sfredo, M. A.; Sousa, G.-D. B.; Limaverde, J. R.
This paper interprets the experimentally measured residence time distribution of coffee berries on a vibrated tray dryer with recycle by means of the dispersion coefficients and the Peclet number. Drying was carried out on a vibrated tray dryer operating with recycle consisting of four parts: a vertical drying tunnel, vibration system, warm air supply to the drying tunnel and recycle system of coffee berries. Using the stimulus-response method the flow behavior of the coffee berries was examined. The dispersion coefficients were calculated by the Taylor Dispersion Model and Free Dispersion Model. The differences in prediction of the dispersion coefficient between the two models were appreciable, but the more reliable values for the dispersion coefficients Ez were those obtained by the Free Dispersion Model. The dispersion coefficient (Free Dispersion) ranged from 2.32x10-4 to 76.81x10-4 m2/s. The average Peclet number, Pe was approximately equal to 6.5, despite greatest variation of the Ez. Therefore, flow velocity variation of coffee berries was the same magnitude of the dispersion coefficient variation.
Bayman, P.; Baker, J. L.
Ochratoxins have been overshadowed by better-known mycotoxins, but they are gaining importance. Here we consider ochratoxins in the context of aflatoxins, which are better understood than ochratoxins on many levels. We review recent work on taxonomic distribution, contamination of commodities, biosynthesis, toxicity and regulatory aspects of ochratoxins. We focus on ochratoxins in coffee, since coffee is becoming a key commodity in ochratoxin research and regulation.
Nava, I.; Gaime-Perraud, I.; Huerta-Ochoa, S.; Favela-Torres, E.; Saucedo-Castaneda, G.
Coffee pulp (CP) is rich in soluble sugars, but it spoils easily and its utilization is limited by its content of caffeine and antinutritional compounds, such as tannins and polyphenols. This study investigated growth of Penicillium commune, a fungus that degreades caffeine and polyphenols, on coffee pulp by solid state fermentation. Effects of thermal pre-treatment (121°C for 10-40 min) of the coffee pulp, incubation temp. (25-35°C) and mixing during fermentation were investigated on spore production by P. commune. Experiments were conducted on both a laboratory and a pilot plant scale. Thermal pretreatment of the coffee pulp had no impact on sporulation. Spore yields were max. at an incubation temp. of 25°C, were increased by continuous mixing and were not affected by scaling up of the fermentation process.
Source : J Chem Technol Biotech 2006 vol. 81 (11), pp 1760 - 1766
Lantz, I.; Ternite, R.; Wilkens, J.; Hoenicke, K.; Guenther, H.; van der Stegen, G. H.
The content of acrylamide in coffee reaches a peak early in the roasting process, reflecting occurrence of both formation and destruction of acrylamide during roasting. Levels of acrylamide in the fully roasted product are a small fraction of the peak reached earlier. Glucose and moisture in green coffee do not show a significant correlation with acrylamide in roasted coffee. Pre-roasting levels of asparagine show a correlation only in Arabica coffee. The main factors affecting the level of acrylamide in roasted coffee appear to be the Arabica/Robusta ratio, with Robusta giving higher levels; time and degree of roast, with both shorter and lighter roasting at the edges of the normal roasting range giving higher levels; storage condition and time, with clear reduction at ambient storage. This storage reduction of acrylamide followed second order reaction kinetics with an activation energy of 73 KJ/mole. The acrylamide in roasted coffee is largely extracted into the brew and stable within usual time of consumption. As these four main factors also substantially affect the sensorial characteristics of the brew, and as modifications of the process have to comply with the consumer-accepted boundaries of taste profiles, only small effects on the acrylamide level are expected to be achievable.
Source : Mol Nutr Food Res 2006 vol. 50 (11), pp 1039 – 1046
Tokumura, M.; Ohta, A.; Znad, H. T.; Kawase, Y.
The photochemical decolorization of coffee effluent has been examined by photo-Fenton (UV/Fe(2+)/H(2)O(2)) process. Effects of UV light intensity, initial coffee concentration, iron dose and H(2)O(2) dose on the color removal of model coffee effluent have been investigated. The rate of decolorization increased with decreasing initial coffee effluent concentration. It was found that the Fe ion dose and UV light intensity enhanced the decolorization rate. The decolorization process of coffee effluent could be divided into three established phases. At the beginning of the photo-Fenton process, the instantaneous and significant increase in color of the solution was found (Phase-I). In the subsequent phase (Phase-II), the decolorization rate was initially fast and subsequently decreased. In Phase-III, the rate was accelerated and then the complete decolorization of model coffee effluent was achieved. In order to elucidate the mechanisms of coffee effluent color removal process, the concentration changes in Fe(3+) and Fe(2+) besides H(2)O(2) were measured during the course of the photo-Fenton process. The rate-determining step in Phase-II was the photo-Fenton reaction or photoreduction of Fe(3+). On the other hand, the decolorization process in Phase-III was highly affected by Fenton reaction or decomposition of H(2)O(2) with Fe(2+). About 93% mineralization of 250mgL(-1) model coffee effluent was achieved after 250min. A comparative study for TiO(2), ZnO and photo-Fenton oxidation processes has been also carried out and the photo-Fenton process was found to be the most effective for color removal of coffee effluent.
Botelho, F.; Lunet, N.; Barros, H.
We systematically reviewed the literature on the association between coffee consumption and gastric cancer and performed a meta-analysis of the results. Published cohort and case-control studies were identified in PubMed and reference lists. Random effects meta-analysis was used to pool effects from 23 studies, and heterogeneity was explored by stratification and meta-regression. The odds ratio (OR) for the overall association between coffee and gastric cancer (highest vs. lowest category of exposure) was 0.97 (95%CI: 0.86-1.09), similar for cohort (OR = 1.02; 95%CI: 0.76-1.37) and case-control studies (population-based: OR = 0.90; 95%CI: 0.70-1.15; hospital-based: OR = 0.97; 95%CI: 0.83-1.13). The OR was 1.26 (95%CI: 1.02-1.57) when considering five studies conducted in the USA, 0.97 (95%CI: 0.82-1.14) for the five Japanese studies, 0.98 (95%CI: 0.81-1.17) for the six studies from Europe, and 0.64 (95%CI: 0.47-0.86) for the two studies from South America. In this meta-analysis we found no adverse effect of coffee associated with gastric cancer. Knowledge on the level of exposure to different coffee constituents may provide a deeper understanding of this reassuring result and the real role of coffee on cancer risk.
Paynter, N. P.; Yeh, H. C.; Voutilainen, S.; Schmidt, M. I.; Heiss, G.; Folsom, A. R.; Brancati, F. L.; Kao, W. H.
The authors analyzed data from a prospective, community-based cohort to assess the risk of incident type 2 diabetes mellitus associated with coffee and sweetened beverage consumption. They included 12,204 nondiabetic, middle-aged men and women in the Atherosclerosis Risk in Communities (ARIC) Study (1987-1999). Consumption of each beverage was assessed by food frequency questionnaire and classified into categories of cups per day. They found an inverse association, after adjusting for potential confounders, between increased coffee consumption and risk of type 2 diabetes mellitus in men (for >/=4 cups (>/=0.95 liter)/day compared with almost never: hazard ratio = 0.77, p(trend) = 0.02) with no significant association in women (hazard ratio = 0.89, p(trend) = 0.32) using a combination of self-report of physician-diagnosed diabetes, diabetes treatment, and a fasting or nonfasting blood glucose test. When self-reported diabetes or diabetes treatment alone was used, a stronger and significant inverse association was seen in men and women. Sweetened beverage consumption (men: hazard ratio = 1.03, p(trend) = 0.94; women: hazard ratio = 1.01, p(trend) = 0.58) showed no consistent association with the incidence of type 2 diabetes mellitus. In summary, increased coffee consumption was significantly associated with a decreased risk of diagnosed type 2 diabetes mellitus in community-based US adults.
Ohfuji, S.; Fukushima, W.; Tanaka, T.; Habu, D.; Tamori, A.; Sakaguchi, H.; Takeda, T.; Kawada, N.; Seki, S.; Nishiguchi, S.; Shiomi, S.; Hirota, Y.
Several studies have reported the role of coffee for hepatocellular carcinoma (HCC). However, no study investigated about the relation of coffee for HCC among individuals with a relevant risk factor, i.e., hepatitis C virus (HCV) infection. Thus, we conducted a hospital-based case-control study to assess an association between coffee and HCC, in which both 73 cases and 253 controls were patients with chronic type C liver disease. To consider potential changes in coffee intake due to progression of liver disease, the effect of coffee was estimated separately before and after first identification of liver disease. Odds ratios (OR) and 95% confidence intervals (CI) for HCC risk were calculated using the conditional logistic regression model. Coffee drinking on a daily basis (>/=1cup/day) revealed lowered ORs as compared with non-drinkers both before first identification of liver disease (OR 0.38; 95% CI: 0.13-1.12; P=0.078) as well as thereafter (OR 0.19; 95% CI: 0.05-0.71; P=0.032). Even after excluding subjects who reported a reduction in the frequency of coffee intake after first identification of liver disease, this negative correlation persisted (OR 0.35; 95% CI: 0.12-1.06; P=0.063). Taken together, coffee may be a protective factor for HCC among those infected with HCV.
Smith, B.; Wingard, D. L.; Smith, T. C.; Kritz-Silverstein, D.; Barrett-Connor, E.
The purpose of this study was to investigate the association between coffee intake and incident diabetes based on an oral glucose tolerance test (OGTT) and examine coffee habits in those with impaired glucose separately from those with normal glucose at baseline. RESEARCH DESIGN AND METHODS: In this prospective study, 910 adults aged >/=50 years without diabetes at baseline in 1984-1987 were followed to 1992-1996, an average of 8 years after assessment of coffee intake. Logistic regression models were adjusted for sex, age, physical activity, BMI, smoking, alcohol, hypertension, and baseline fasting plasma glucose. RESULTS: Past and current coffee drinkers had a reduced risk of incident diabetes (odds ratio 0.38 [95% CI 0.17-0.87] and 0.36 [0.19-0.68], respectively) compared with those who never drank coffee. The 317 participants with baseline impaired glucose who were past or current coffee drinkers were also at reduced risk for incident diabetes (0.31 [0.11-0.87] and 0.36 [0.16-0.83], respectively).
CONCLUSIONS: This study confirms a striking protective effect of caffeinated coffee against incident diabetes and extends these findings to incident diabetes based on OGTT independent of multiple plausible confounders.
Kumao, T.; Fujii, S.; Asakawa, A.; Takehara, I.; Fukuhara, I.
A liquid coffee drink containing mannooligosaccharides from coffee mannan (MOS) was administered to a group of healthy adults. Subsequently, the amount of fat excreted from the body was examined. The subjects were divided into two groups: One was administered a liquid coffee drink containing MOS 3.0 g/day whereas the other was administered a placebo drink for seven days. Both groups were fed the standardized meals during the experiment. In the amount of average excreted fat, the drink containing MOS intake showed a significant increase in comparison with the before intake group and placebo intake group (p < 0.05 and p < 0.001, respectively). In addition, fat utilization in MOS intake group was significantly lower than the before intake group and the placebo group (p < 0.05 and p < 0.001, respectively). These results suggested that the intake of MOS 3.0 g/day increased in the amount of excreted fat and decreased in fat utilization.
Tsioufis, C.; Dimitriadis, K.; Vasiliadou, C.; Taxiarchou, E.; Vezali, E.; Tsiamis, E.; Stefanadis, C.; Kallikazaros, I.
Klug, T. L.; Bageman, E.; Ingvar, C.; Rose, C.; Jernstrom, H.
Most, but not all, studies have found that women with a high urinary 2-hydroxyestrogen (2OHE) to 16alpha-hydroxyestrone (16alphaOHE1) ratio are at reduced risk for breast cancer and have a better prognosis. The aim was to identify factors associated with the pre-operative 2OHE to 16alphaOHE1 ratio and factors that predicted the change in the ratio between the pre-operative visit and first follow-up visit three to six months post-operatively among 59 women with primary ER positive breast cancer tumors. Body measurements, questionnaires and blood samples for measurements of the 2OHE and 16alphaOHE1 plasma levels and CYP1A2 *1F genotyping were collected at both visits. Post-operatively, 15 women received tamoxifen, 30 women tamoxifen and radiotherapy concomitantly, and 14 women radiotherapy. The pre-operative ratio was not correlated with tumor characteristics, but was significantly higher in women who consumed three or more cups of coffee daily (p=0.009). The number of CYP1A2 *1F C-alleles was correlated with a lower ratio at both visits (p=0.13 and p=0.02, respectively). The ratio increased between the two visits in 69.5% of the women. The factors associated with a significant increase in the ratio were concomitant tamoxifen and radiotherapy (p=0.006), increasing alcohol consumption (p=0.006), and a high coffee consumption (p=0.03), but not age or CYP1A2 *1F genotype. In this pilot study, breast cancer patients who started tamoxifen during radiotherapy and who had a moderate coffee and alcohol consumption demonstrated a significant improvement in their estrogen metabolite profile between the pre- and post-operative visits.
Murkovic, M.; Pichler, N.
5-Hydroxymethylfurfural has become a substance of interest since recent results showed a possible carcinogenic potential in consequence of a metabolic activation by sulfotransferases. 5-Hydroxymethylfurfural is formed either by acid catalysed degradation of reducing sugars or via the Maillard reaction. This work provides an overview of foods potentially containing high amounts of 5-hydroxymethylfurfural. It comprises dried fruits with a high sugar content that were exposed to heat for a long time. The concentration ranges from very low in, e. g. figs (1 mg/kg) to plums that contained up to 2,200 mg/kg. Several types of roasted coffee were analysed that contained from 300 to 2,900 mg/kg of 5-hydroxymethylfurfural. In a small human study with seven healthy volunteers the urine excretion of unmetabolised 5-hydroxymethylfurfural was investigated. After uptake of 20 g of plum jam containing 24 mg of 5-hydroxymethylfurfural, 163 microg (mean) were excreted within 6 h, an equivalent of 0.75% of the ingested 5-hydroxymethylfurfural.
Aguas, P. C.; Fitzhenry, M. J.; Giannikopoulos, G.; Varelis, P.
An accurate and precise method for the quantification of acrylamide using stable isotope dilution LC-tandem MS was developed and used to measure acrylamide in coffee and cocoa samples. Sample preparation involves extraction of the analyte and its internal standard, 13C3-acrylamide, into water and subsequent defatting of the aqueous extract with dichloromethane. An aliquot of the resulting aqueous extract is then azeotropically dried under reduced pressure and subsequently purified using an aminopropyl-bonded silica cartridge. The purified extracts are then chromatographed on a 5 mum 2.1 x 150 mm Hypercarb column, the effluent of which is monitored for the analyte and its internal standard using positive-ion APCI-selected reaction monitoring. The intra-laboratory reproducibility of the method, expressed as a relative coeff. of variation (n = 5), was determined at acrylamide concn. of 12.3, 42.3, 139.3 and 464.8 mug/kg and was found to vary in the range 0.6-2.5%. Method accuracy was assessed using a reference sample of coffee. The average result obtained using the developed method differed from the certified value by <1%. Analysis of a cocoa sample revealed that the method is capable of precisely estimating acrylamide in challenging matrices down to a level of 12.3 mug/kg or lower.
Source : Anal Bioanal Chem 2006 vol. 385 (8), pp 1526 - 1531
Ocampo, J. A.; Giraldo, G. I.
Use of the Weibull hazard model for prediction of instant coffee shelf life as a function of storage conditions and packaging materials was studied. Spray-dried instant coffee was packaged in paper-based laminate, carton or glass containers and stored at 25, 30, 35 or 40°C (90% RH) for <less than or equal to>132 days. Changes in sensory acceptability were determined during storage and a model based on Weibull distribution was able to satisfactorily determine shelf life in relation to storage temp. and packaging material by calculating time when 50% of consumers would find the product unacceptable. Model findings were used to calculate shelf life at 18°C (90% RH) as 279, 466 and 624 days for instant coffee packaged in paper laminates, carton and glass, respectively.
Source : Alimentacion Equipos y Tecnologia 2006 vol. 25 (210), pp 107 - 111
Lopez-Galilea, I.; Fournier, N.; Cid, C.; Guichard, E.
Headspace-solid-phase microextraction technique (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O) were used to characterize the aroma compounds of coffee brews from commercial conventional and torrefacto roasted coffee prepared by filter coffeemaker and espresso machine. A total of 47 volatile compounds were identified and quantified. Principal component analysis (PCA) was applied to differentiate coffee brew samples by volatile compounds. Conventional and torrefacto roasted coffee brews were separated successfully by principal component 1 (68.5% of variance), and filter and espresso ones were separated by principal component 2 (19.5% of variance). By GC olfactometry, a total of 34 aroma compounds have been perceived at least in half of the coffee extracts and among them 28 were identified, among which octanal was identified for the first time as a contributor to coffee brew aroma.
Soares, C.; Cunha, S.; Fernandes, J.
An improved gas chromatography-mass spectrometry (GC-MS) method to determine acrylamide (AA) in coffee and coffee products was developed. The method was based on two main purification steps: the first with ethanol and Carrez solutions in order to precipitate polysaccharides and proteins, respectively; and the second with a layered solid-phase extraction (SPE) column which proved to be efficient in the elimination of the main chromatographic interferences. The method is applicable to a wide range of coffee products. Twenty-six samples of different coffee products were analysed. The levels of AA were in the range 11.4-36.2 microg l-1 for \'espresso coffee\' and 200.8-229.4 microg l-1 for coffee blends with cereals. The results indicate that the presence of cereals significantly increased the levels of AA.
Source : Food Addit Contam 2006 vol.23 (12 ), pp 1276 - 1282
Fischer, A.; Schieberle, P.
This item summarises research into the influence of oxygen on flavour changes in roast ground coffee during storage. The concentration of ten of the 28 most potent flavour compounds in Arabica roast coffees were analysed in a range of packaging formats, including oxygen-free atmospheres using argon. The importance of optimising packaging to reduce oxygen exposure during storage was highlighted.
Source : Lebensmittelchemie 2006 vol. 60 (5), pp 117-118 (not available on-line)
Mattila, P.; Hellstrom, J.; Torronen, R.
The contents of soluble and total phenolic acids were analysed in samples of 29 berries and berry products, 24 fruits and fruit peels, and 12 beverages. Variation of phenolic acids in berries was also studied. Soluble phenolic acids were extracted with methanolic acetic acid, and a tentative quantification was performed by HPLC. The total phenolic acid content was determined by HPLC after alkaline and acid hydrolyses. The content of total phenolic acids as aglycones in the samples varied from 0 (pear cider) to 103 mg/100 g fresh wt. (rowanberry). Besides rowanberry, the best phenolic acid sources among berries were chokeberry (96 mg/100 g), blueberry (85 mg/100 g), sweet rowanberry (75 mg/100 g) and saskatoon berry (59 mg/100 g). Among fruits, the highest contents (28 mg/100 g) were determined in dark plum, cherry and one apple var. (Valkea Kuulas). Coffee (97 mg/100 g), as well as green and black teas (30-36 mg/100 g), was the best sources among beverages. Caffeic acid dominated in all of these samples except in tea brews. Variation in the phenolic acid contents of the berries was either small or moderate.
Vargas, E. A.; Whitaker, T. B.; Santos, E. A.; Slate, A. B.; Lima, F. B.; Franca, R.-C. A.
Green coffee shipments are often inspected for ochratoxin A (OTA) and classified into good or bad categories depending on whether the OTA estimates are above or below a defined regulatory limit. Due to the uncertainty associated with the sampling, sample preparation and analytical steps of an OTA test procedure, some shipments of green coffee will be misclassified. The misclassification of lots leads to some good lots being rejected (sellers\' risk) and some bad lots being accepted (buyers\' risk) by an OTA sampling plan. Reducing the uncertainty of an OTA test procedure and using an accept/reject limit less than the regulatory limit can reduce the magnitude of one or both risks. The uncertainty of the OTA test procedure is most effectively reduced by increasing sample size (or increasing the number of samples analysed), because the sampling step is the largest source of uncertainty in the OTA test procedure. In this study, effects of increasing sample size and changing the sample accept/reject limit relative to the regulatory limit were investigated on the performance of OTA sampling plans for green coffee. For a given accept/reject limit of 5 mug/kg, increasing sample size increased the percentage of lots accepted at concn. below the regulatory limit and increased the percentage of lots rejected at concn. above the regulatory limit. As a result, increasing sample size reduced both the number of good lots rejected (sellers\' risk) and the number of bad lots accepted (buyers\' risk). For a given sample size (1 kg), decreasing the sample accept/reject limit from 5 to 2 mug/kg relative to a fixed regulatory limit of 5 mug/kg decreased the percentage of lots accepted and increased the percentage of lots rejected at all OTA concn. As a result, decreasing the accept/reject limit below the regulatory limit increased the number of good lots rejected (sellers\' risk), but decreased the number of bad lots accepted (buyers\' risk). [See FSTA 2005-11-Hn2822 for part II.].
Myles, A. J.; Zimmerman, T. A.; Brown, S. D.
Analogous to the situation found in calibration, a classification model constructed from spectra measured on one instrument may not be valid for prediction of class from spectra measured on a second instrument. In this paper, the transfer of multivariate classification models between laboratory and process near-infrared spectrometers is investigated for the discrimination of whole, green Coffea arabica (Arabica) and Coffea canefora (Robusta) coffee beans. A modified version of slope/bias correction, orthogonal signal correction trained on a vector of discrete class identities, and model updating were found to perform well in the preprocessing of data to permit the transfer of a classification model developed on data from one instrument to be used on another instrument. These techniques permitted development of robust models for the discrimination of green coffee beans on both spectrometers and resulted in misclassification errors for the transfer process in the range of 5-10%.
Spaniolas, S.; May, S. T.; Bennett, M. J.; Tucker, G. A.
Coffee is one of the most important world food commodities, commercial trade consisting almost entirely of Arabica and Robusta varieties. The former is considered to be of superior quality and thus attracts a premium price. Methods to differentiate these coffee species could prove to be beneficial for the detection of either deliberate or accidental adulteration. In this study, a molecular genetics approach designed to differentiate Arabica and Robusta coffee beans was developed. The assay employs PCR-RFLP to monitor a single nucleotide polymorphism within the chloroplastic genome. Samples were analysed with a lab-on-a-chip capillary electrophoresis system. Results showed a 5% limit of detection in coffee powder mixtures analysed with this technique. The plastid copy number was found to be relatively constant across a wide range of bean samples, suggesting that this method can also be employed for the quantification of any adulteration of Arabica with Robusta beans.
Source : J Agric Food Chem 2006 vol. 54 (20), pp 7466 - 7470