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The chemical parameters pH, soluble solids, caffeine, trigonelline, total chlorogenic acids, total caffeoylquinic acids, 3-O-caffeoylquinic acid, 4-O-caffeoylquinic acid, 5-O-caffeoylquinic acid, total dicaffeoylquinic acids, 3,4-O-dicaffeoylquinic acid, 3,5-O-dicaffeoylquinic acid, 4,5-O-dicaffeoylquinic acid, total feruloylquinic acids, 3-O-feruloylquinic acid and 5-O-feruloylquinic acid were measured in Arabica (C. arabica) and Robusta (C. canephora) green coffees in order to determine discrimination parameters. In general Robusta green coffee showed higher values for pH, soluble solids, caffeine, total caffeoylquinic acids, total dicaffeoylquinic acid and total feruloylquinic acid, but the content of soluble solids was not significantly different in both species of green coffee. Through application of a multivariate analysis it was concluded that these chemicals form three clusters, being the group of caffeine, trigonelline, 3-O-caffeoylquinic acid, 4-O-caffeoylquinic acid, 3-O-feruloylquinic acid, 5-O-feruloylquinic acid, 3,4-O-dicaffeoylquinic acid, 3,5-O-dicaffeoylquinic acid and 4,5-O-dicaffeoylquinic acid highly discriminating for Arabica and Robusta green coffees.
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Identification of Chemical Clusters
Discriminators of Arabica and Robusta
Green Coffee
Natalina Cavaco Bicho a b , António Eduardo Leitão b , José Cochicho
Ramalho b , Nuno Bartolomeu de Alvarenga c & Fernando Cebola
Lidon a
a Departamento de Ciências e Tecnologia da Biomassa, Faculdade
de Ciências e Tecnologia , Universidade Nova de Lisboa , Caparica ,
Portugal
b Centro de Ecofisiologia, Bioquímica e Biotecnologia Vegetal,
Instituto de Investigação Científica Tropical, I.P., Quinta do
Marquês , Oeiras , Portugal
c Departamento de Tecnologias e Ciências Aplicadas , Escola
Superior Agrária, Instituto Politécnico de Beja , Beja , Portugal
Accepted author version posted online: 09 Aug 2012.Published
online: 27 Feb 2013.
To cite this article: Natalina Cavaco Bicho , António Eduardo Leitão , José Cochicho Ramalho ,
Nuno Bartolomeu de Alvarenga & Fernando Cebola Lidon (2013) Identification of Chemical Clusters
Discriminators of Arabica and Robusta Green Coffee, International Journal of Food Properties, 16:4,
895-904, DOI: 10.1080/10942912.2011.573114
To link to this article: http://dx.doi.org/10.1080/10942912.2011.573114
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International Journal of Food Properties, 16:895–904, 2013
Copyright © Taylor & Francis Group, LLC
ISSN: 1094-2912 print / 1532-2386 online
DOI: 10.1080/10942912.2011.573114
IDENTIFICATION OF CHEMICAL CLUSTERS
DISCRIMINATORS OF ARABICA AND ROBUSTA
GREEN COFFEE
Natalina Cavaco Bicho1,2, António Eduardo Leitão2,José
Cochicho Ramalho2, Nuno Bartolomeu de Alvarenga3,
and Fernando Cebola Lidon1
1Departamento de Ciências e Tecnologia da Biomassa, Faculdade de Ciências e
Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal
2Centro de Ecofisiologia, Bioquímica e Biotecnologia Vegetal, Instituto de
Investigação Científica Tropical, I.P., Quinta do Marquês, Oeiras, Portugal
3Departamento de Tecnologias e Ciências Aplicadas, Escola Superior Agrária,
Instituto Politécnico de Beja, Beja, Portugal
The chemical parameters pH, soluble solids, caffeine, trigonelline, total chlorogenic
acids, total caffeoylquinic acids, 3-O-caffeoylquinic acid, 4-O-caffeoylquinic acid, 5-
O-caffeoylquinic acid, total dicaffeoylquinic acids, 3,4-O-dicaffeoylquinic acid, 3,5-
O-dicaffeoylquinic acid, 4,5-O-dicaffeoylquinic acid, total feruloylquinic acids, 3-O-
feruloylquinic acid, and 5-O-feruloylquinic acid were measured in Arabica (C. arabica)
and Robusta (C. canephora) green coffees in order to determine discrimination parameters.
In general, Robusta green coffee showed higher values for pH, soluble solids, caffeine, total
caffeoylquinic acids, total dicaffeoylquinic acid, and total feruloylquinic acid, but the con-
tent of soluble solids was not significantly different in both species of green coffee. Through
application of a multivariate analysis, it was concluded that these chemicals form three clus-
ters, being the group of caffeine, trigonelline, 3-O-caffeoylquinic acid, 4-O-caffeoylquinic
acid, 3-O-feruloylquinic acid, 5-O-feruloylquinic acid, 3,4-O-dicaffeoylquinic acid, 3,5-O-
dicaffeoylquinic acid, and 4,5-O-dicaffeoylquinic acid highly discriminating for Arabica and
Robusta green coffees.
Keywords: Arabica green coffee, Caffeine, Chlorogenic acids, Robusta green coffee,
Trigonelline.
INTRODUCTION
The cell wall of the coffee bean epidermis is surrounded by crystallized waxes,
whereas chlorogenic acid, terpenes, and derivatives of 5 hydroxytryptamine (serotonin)
prevail in the cuticular layer. The chlorogenic acids further accumulate in the cytoplasm of
epidermal and parenchyma cells, but larger quantities can be found in the periplasm. In the
cytoplasm of parenchyma cells, caffeine is also associated with chlorogenic acid (forming
Received 11 October 2010; accepted 15 March 2011.
Address correspondence to Fernando Cebola Lidon, Departamento Ciências e Tecnologia da Biomassa,
Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus da Caparica, Caparica 2829-516,
Portugal. E-mail: fjl@fct.unl.pt
895
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896 BICHO ET AL.
a potassium chlorogenate complex) and metallic salts further occur in the form of calcium
ions of phosphate and potassium.[1,2]
In Arabica (Coffea arabica L.) and Robusta (Coffea canephora Pierre ex A.Froehn)
green coffees, pH usually is ca. 5.2–6.1,[3] while soluble solids correspond to 24–27 and
26–31 g/100 g coffee, respectively.[4] The caffeine levels of green coffee beans might vary
between 0.8–2.5 g/100 g coffee. Nevertheless, although some coffee species may present
low levels of caffeine, in Arabica and C. Canephora (for both cvs. Robusta and Conilon),
they are usually between 0.8–1.5 and 1.6–2.2 g/100 g coffee, respectively. Trigonelline
contents correspond to about 0.6 g/100 g coffee, but almost 50% of this compound is
degraded during roasting,[5] with the formation of other compounds, namely nicotinic
acid, pyridine, 3-methyl-pyridine, and methyl ester of nicotinic acid. Caffeoylquinic acids
(CQAs), dicaffeoylquinic acids (diCQA), and feruloylquinic acids (FQA) account for about
98% of total chlorogenic acids (CGA) in green coffee.[6] The hydroxycinnamic acids are
also particularly common in coffee beans, especially as chlorogenic acid (4–8 g/100 g
coffee) in the double form of caffeine and potassium chlorogenate,[7,8] but they are
significantly destroyed during roasting, with the release of the correspondent alkaloid.[9,10]
It has long been known that chemical composition of green coffee beans depends
on the genotypes and geographic area of origin, as well as of cultural practices, matura-
tion, and post-harvest conditions, particularly storage.[11] Considering these parameters,
this work aims to identify chemical discriminators that might be applied to differentiate the
majority of commercial Arabica and Robusta green coffee beans. Accordingly, the chem-
ical composition of Arabica and Robusta green coffees from Brazil and India was carried
out, being a multivariate analysis applied to identify chemical clusters that might be useful
as discriminators of these green coffee types.
MATERIALS AND METHODS
Sampling of Coffea arabica L. (from Brazil) and Coffea canephora Pierre ex
A.Froehn (from India) was carried out according to the Instrução Normativa No. 8,[12] NP
1666,[13] and ISO 4072,[14] as recommended by the ICO for sampling green coffee in bags.
The sampling process began with a randomized (a minimum of 10% of the lot) collection
of green coffee bags.[15] The selected bags were separated from the lot and each one was
collected in triplicate (with a probe of 30 ±6 g of green coffee beans) from three differ-
ent points in the bag (top, middle, and bottom). After extraction and homogenization, the
portions were joined, for an overall take of green coffee, with a minimum mass of 1.5 kg.
Soluble solids and pH were measured according to the AOAC,[16,17] at 25C, after cal-
ibration of the electrode with pH 4.0 and 7.0 buffer solutions. Ground green coffee (10 g ±
0.1 mg) mixed with water (200 mL) was boiled for 5 min, cooled at room temperature, and
the weight adjusted by adding water. After filtration with a Whatman No. 1 filter, the pH of
the filtrate was measured at room temperature. For quantification of soluble solids, 25 mL
of the filtrate were dried in a water bath until dryness, after which the residue was placed
in an oven at 105C, cooled in a desiccator, and weighed. Data is the average of triplicate
for each sample of green coffee.
Caffeine and trigonelline contents were measured according to ISO 10095.[18]
Samples of ground green coffee (1 g ±0.1 mg) were homogenized with magnesium oxide
(4.5 ±0.5 g) and water (100 mL) and placed in a water bath at 90C with continuous
stirring for 20 min. After cooling, the weight was restored to the original level and the
mixture filtered through a Whatman No. 1 filter, without washing the residue. An aliquot
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CHEMICAL DISCRIMINATORS OF GREEN COFFEE 897
of 2 mL of the filtered mixture was diluted with distilled water to a volume of 10 mL and
filtered through a 0.45 µm filter. Thereafter, caffeine quantification was carried out in an
integrated HPLC system (Waters, Milford, MA, USA; equipped with an UV-VIS detector,
model 440, column Lichrosorb 100 RP-18, Merck, Darmstadt, Germany; 5 µm particle
size, 4 ×250 mm), being used with 32 Karat Software (V. 7.0, Beckman Coulter, Inc.,
Brea, CA, USA). The elution of a 20 µL injection was performed at 25C, with a 1 mL
min1flow rate, using phosphate buffer (20 mM; pH 4.3) and acetonitrile (9:1), with detec-
tion at 254 nm. Identification and quantification was performed using standard curves, with
concentrations between ca. 8–1000 µgmL
1for caffeine, and between ca. 8–500 µgmL
1
for trigonelline. Data were within the detection limits of the method. All extractions and
chromatographic analysis were performed in triplicate.
Chlorogenic acids extraction and analysis followed Correia[9] and Fortunato et al.[19]
After mixing 2 g ±0.1 mg of ground green coffee to 10 mL of methanol:water (40:60),
and mechanical agitation for 30 min, the mixture was centrifuged (9400 g, 5 min, 25C)
and the supernatant decanted. Thereafter, 1 mL of Carrez solutions I (aqueous solution of
Zn acetate dihydrate and glacial acetic acid, 10.95 g and 1.5 mL, respectively, to a final
volume of 50 mL) and II (aqueous solution of 5.3 g of potassium hexacyanoferrate II trihy-
drate in a final volume of 50 mL) were added for clarification of the sample, after which a
methanol:water (40:60) solution was added to a final volume of 100 mL. After resting for
15 min, the mixture was filtered through a Whatman No. 1 filter and an aliquot of 10 mL was
removed from the filtrate and filtered through 0.45 µm. For quantification, an HPLC system
(Beckman Coulter System Gold, Beckman Coulter, Inc.) equipped with a diode array detec-
tor (model 168), a reverse phase column (Spherisorb S5 ODS-2, Waters; 4.6 ×250 mm) and
32 Karat Software (V. 7.0, Beckman Coulter, Inc.) was used. The elution of a 20 µL injec-
tion was performed at ca. 25C,over45min,witha1mLmin
1flow rate, using an opti-
mized linear gradient 20–70% of B (solvent A tripotassium citrate buffer solution 10 mM,
pH 2.5, and solvent B methanol 100%). Detection was performed at 325 and 330 nm.
For isomerisation of chlorogenic acid (caffeoylquinic acids), 200 mg of
5-caffeoylquinic acid was diluted in 20 mL of distilled water and the pH adjusted to 8 with
ammonium hydroxide (4 M). Then, the solution was boiled for 30 min in a water bath,
cooled, and the pH adjusted to 2.5 with HCl (4 M). After that filtration samples were used
for quantification. The identification of chromatographic peaks and quantification of results
was carried out using standard solutions of 5-CQA. To identify the isomers 3-CQA and 4-
CQA, the standard 5-CQA isomer was subjected to isomerization, as described. The peaks
appeared with the following sequence: 3-CQA, 3-FQA, 4-CQA, 5-CQA, 4-FQA, 5-FQA,
3,4-diCQA, 3,5-diCQA, and 4,5-diCQA. The calibration curve was obtained from 5-CQA
with readings at 325 and 330 nm. The quantification was done assuming the peak areas as
a reference and comparing them with the standard 5 CQA. To quantify each compound, the
following equation was used:[9,20]
c=Fr ×ε1×Mr2×A
ε2×Mr1
,
where c is the concentration of the isomer to quantify, in mg L1; Fr is the response factor
of the standard 5-CQA in mg L1per unit area; ε1is the molar absorption coefficient of the
standard 5-CQA in L mol1cm1;ε2is the molar absorption coefficient of the isomer to
quantify, in L mol1cm1;Mr
2is the molecular weight on the isomer under study—CQA
=354.31 g mol1,FQA=368.28 g mol1,diCQA=516.44 g mol1;Mr
1is the molar
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898 BICHO ET AL.
mass of acid 5-CQA; A is the peak area of the isomer to be quantified. The molar absorption
coefficients (3-CQA =18,400, 4-CQA =18,000, 5-CQA =19,500, 3,4-diCQA =31,800,
3,5-diCQA =31,600, 4,5-diCQA =33,200, with λ=330 nm; 3-FQA =19,000, 4-FQA
=19,500, 5-FQA =19,300, with λ=325 nm) indicated by Correia[9] and Farah et al.,[20]
in L mol1cm1, were used. Data were within the detection limits of the method. All
extractions and chromatographic analysis were performed in triplicate.
Data were statistically analyzed using a one-way ANOVA (P0.05). Based on
the ANOVA results, a Tukey’s test was performed for mean comparison, for a 95% con-
fidence level. Different letters indicate significant differences for 95% confidence level.
Multivariate analysis was carried out with STATISTICA 6.0 software (Copyright StatSoft,
Inc., Tulsa, OK, USA), following several authors.[21–25]
RESULTS AND DISCUSSION
Coffee acidity depends on the geographic origin of green coffee beans, fruits matu-
rity, harvest process, weather conditions during harvesting and drying, and post-harvest
processing.[26,27] Additionally, coffee acidity might also be determined by growth condi-
tions, such as altitude[26,28] and shading,[28] but Robusta coffees are considered to have
low acidity, unlike the Arabica coffees. Although the average values were not dramatically
apart, the pH of Arabica green coffee was significantly lower than the Robusta green coffee,
with values ranging between 5.26–6.11 and 5.27–6.13, being in the range pointed out by
Leroy et al.[3] for these coffee types.
Mendonça et al.[4] supported that soluble solids for Arabica and Robusta green cof-
fees might vary between 23.85–27.31 and 26.07–30.6 g/100 g coffee, respectively, whereas
Esteves and Oliveira[29] pointed that in Robusta green coffees those values might vary
between 32.46–34.91 g/100 g coffee. The obtained content of soluble solids (Table 1)
was similar to those obtained by Mendonça et al.[4] for Arabica coffees, and Esteves and
Oliveira[29] for Robusta coffees. The soluble solids assayed in Arabica and Robusta green
coffees were not significantly different, but were slightly higher in Robusta green coffee
(Table 1).
Moreover, caffeine contents varied significantly being higher in the Robusta green
coffee (Table 1), showing much higher values (10- to 20-fold higher) than reported in
leaves, which did not present differences among the Coffea spp. genotypes,[19] contrary
to what is reported here for the bean. In fact, our results followed previous studies in
which Robusta coffees usually have a higher caffeine content than Arabica ones, although
in green coffee the levels of caffeine might vary widely, mostly due to inter-specific
differences.[7,30–33] Indeed, according to Viani,[7] the levels of caffeine might vary between
0.9–1.4 g/100 g in Arabica coffees, and between 1.5–2.6 g/100 g in Robusta ones, whereas
Macrae[30] presented a review of results obtained by various authors, pointing out average
values from 1.16–1.35 and 1.72–2.76 g/100 g coffee for Arabica and Robusta types, respec-
tively. Additionally, Silvarolla et al.[31] in 99 progenies from Ethiopia found caffeine values
varying between 0.42 and 2.9 g/100 g coffee, while in another study of 16 progenies of
C. arabica, tolerant and susceptible to Hemileia vastatrix, the levels ranged from 0.95 to
1.24 g/100 g coffee.[34] Salva and Lima[32] further reported that the caffeine content of
Arabica coffees varies between 1.1 and 1.8 g/100 g coffee.
The content of trigonelline in green coffees might vary with the kind of coffee and
geographical origin, being suggested that this compound could be used to discriminate the
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CHEMICAL DISCRIMINATORS OF GREEN COFFEE 899
Tab le 1 Levels of pH, soluble solids, caffeine, trigonelline, 3-CQA, 4-CQA, 5-CQA, CQAtotal,
3,4-diCQA, 3,5-diCQA, 4,5-diCQA, diCQAtotal, 3-FQA, 5-FQA, FQAtotal ,andCGAof
Arabica and Robusta green coffee.
Green coffee samples
Parameters Arabica Robusta
pH 5.62 ±0.00r5.71 ±0.00s
Soluble solids (g/100 g) 33.32 ±0.07r33.96 ±0.52r
Caffeine (g/100 g) 1.454 ±0.007r2.382 ±0.019s
Trigonelline (g/100 g) 1.385 ±0.014r1.009 ±0.032s
CQA (g/100 g)
3-CQA 0.563 ±0.002r0.631 ±0.004s
4-CQA 0.711 ±0.008r0.801 ±0.002s
5-CQA 4.430 ±0.036r4.703 ±0.007s
CQAtotal 5.704 ±0.044r6.135 ±0.005s
diCQA (g/100 g)
3,4-diCQA 0.201 ±0.002r0.572 ±0.005s
3,5-diCQA 0.395 ±0.003r0.592 ±0.005s
4,5-diCQA 0.226 ±0.003r0.515 ±0.005s
diCQAtotal 0.822 ±0.007r1.680 ±0.014s
FQA (g/100 g)
3-FQA 0.029 ±0.002r0.059 ±0.000s
5-FQA 0.242 ±0.004r0.594 ±0.002s
FQAtotal 0.271 ±0.005r0.653 ±0.002s
CGA (g/100 g) 6.797 ±0.054r8.467 ±0.013s
Each value is the mean ±SE (n=3). Different letters (r, s) indicate significant differences,
in a multiple range analysis, for 95% confidence level.
geographical origin of coffee.[35] However, Aguiar et al.,[36] after examining different vari-
eties of C. canephora, concluded that the differences in content of trigonelline are too small
to constitute a useful tool to discriminate this kind of coffee. In this study, it was found that
the content of the alkaloid trigonelline was significantly higher in Arabica green coffee
(Table 1), therefore showing a pattern similar to previous reports.[30,36,37] Indeed, accord-
ing to Macrae,[30] trigonelline levels in Arabica and Robusta green coffee are around 1 and
0.7 g/100 g coffee, respectively, while Aguiar et al.[36] pointed values between 0.97 to
1.01 g/100 g coffee for green coffee Robusta. Ky et al.,[37] using seeds of C. arabica
and C. canephora from various geographical origins, reported trigonelline levels between
0.88–1.77 and 0.75–1.24 g/100 g coffee, respectively, showing a large variation that turns
this compound not suitable to discrimination.
CQA, diCQA, and FQA represent about 98% of total chlorogenic acids in coffee.[6]
Concerning CQAs, it was found (Table 1) that 5-CQA was the most representative com-
pound both in Arabica and Robusta green coffees, representing ca. 77% of total CQA
content, similarly to what was reported in the leaves of several Coffea spp. genotypes where
it accounts for ca. 85%.[19] Also, the levels of all caffeoylquinic acid isomers (3-CQA, 4-
CQA, and 5-CQA), as well as CQAtotal, were significantly higher in the Robusta green
coffee, within the range pointed out previously.[7,9,37,38]
The content of each isomer of diCQA was clearly and significantly higher in the
Robusta green coffee (Table 1). Quite similar amounts of 3,4-diCQA (0.572 g/100 g cof-
fee), 3,5-diCQA (0.592 g/100 g coffee), and 4,5-diCQA (0.515 g/100 g coffee) were found
in Robusta green coffee, while the isomer 3,5-diCQA (0.395 g/100 g coffee) predominated
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900 BICHO ET AL.
in green Arabica coffee (Table 1). These patterns further followed the values indicated by
several authors.[37,38,39]
In agreement with previous results,[7,9,37,38] the 5-FQA isomer predominates (ca. 90%
of total FQA), being the contents of the others (3-FQA and 4-FQA) much less relevant.
Following previous works,[7,9,37,38] it was also found that Robusta green coffee had signifi-
cantly higher levels of 3-FQA and 5-FQA, as well as a significantly higher total amount of
FQA (Table 1).
The total content of each group of chlorogenic acid (CQAtotal,diCQA
total, and
FQAtotal), as well as CGAtotal , tended to be higher in Robusta green coffees (Table 1),
prevailing 5-CQA in green coffee. In fact, 5-CQA represented more than half (65 and 55%)
of total CGAs in Arabica and Robusta coffees (Table 1). That led to the higher weight
of CQAs, representing 84 and 72% of total CGAs in Arabica and Robusta green coffees,
respectively (Table 1). diCQA acids were the second most abundant group in the diCQAtotal,
corresponding to ca. 12 and 20% of total CGAs, while the FQAs represented ca. 4 and 8%
of the CGAtotal value, assayed in samples of Arabica and Robusta green coffees, respec-
tively. The content of total CGA in Robusta green coffee was ca. 25% higher than in the
Arabica green coffee (Table 1).
A cluster analysis might generate homogeneous groupings and segmentation based
on variables. Considering the pH, soluble solids, caffeine, trigonelline, CQAtotal,di-
CQAtotal, and FQAtotal , a cluster analysis, using a linkage distance around 0.6 (Fig. 1)
allowed a discrimination of Arabica and Robusta samples. Forming of clusters by the cho-
sen data set can result in a new variable that identifies cluster members among the cases.
In this context, Robusta green coffee showed a tendency to, in general, present higher values
for all parameters except trigonelline, but the content of soluble solids was not significantly
different in both species of green coffee (Table 1). These data suggest that the parameters
Figure 1 Samples (n=3) dendogram of Arabica (A) and Robusta (R) coffees considering the parameters pH,
soluble solids, caffeine, trigonelline, CQAtotal,di-CQA
total, and FQAtotal based on Euclidean distances between
them. (Color figure available online.)
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CHEMICAL DISCRIMINATORS OF GREEN COFFEE 901
Figure 2 Green coffees dendogram of: (a) pH, soluble solids, caffeine, trigonelline, CQAtotal,diCQA
total,and
FQAtotal based on Euclidean distances between them; (b) pH, soluble solids, caffeine, trigonelline, the 3-CQA, 4-
CQA, 5-CQA, 3,4-diCQA, 3.5-diCQA, 4.5-DICQ, 3-FQA, and 5-FQA, based on the Euclidean distances between
them. (Color figure available online.)
can be subdivided into three groups, according to their importance for samples discrimi-
nation achieved with the cluster analysis (Figs. 1 and 2). Although the content of soluble
solids were not relevant, the pH and CQAtotal, particularly the fraction 5-CQA, constitute a
second group in terms of its importance in the discrimination of samples (Fig. 2), whereas
caffeine, trigonelline, 3-CQA, 4-CQA, 3-FQA, 5-FQA, 3,4-diCQA, 3,5-diCQA, and 4,5-
diCQA formed a third group of substances, highly discriminating for Arabica and Robusta
green coffees, because they have higher and significantly different values. Accordingly,
and considering that the chemical characterization of Arabica and Robusta green coffee
provided in this study, in general, parallels with the worldwide parameters for these coffee
species, it might be concluded that this third cluster might be used as a universal discrim-
inator. Moreover, considering the roast coffee chemical characteristics, this model cannot
be applied to roast coffee.[40,41]
CONCLUSION
The cluster analysis used for classification of chemical data of Arabica and Robusta
green coffee allowed a partitionation into groups based on a distance/dissimilarity func-
tion. In this context, caffeine, trigonelline, 3-O-caffeoylquinic acid, 4-O-caffeoylquinic
acid, 3-O-feruloylquinic acid, 5-O-feruloylquinic acid, 3,4-O-dicaffeoylquinic acid, 3,5-O-
dicaffeoylquinic acid, and 4,5-O-dicaffeoylquinic acid can be considered a chemical cluster
discriminator for Arábica and Robusta green coffees. Moreover, pH, soluble solids, 5-O-
caffeoylquinic acid, total chlorogenic acids, total caffeoylquinic acids, total feruloylquinic
acids, and total dicaffeoylquinic acids should not be used as discriminators, because their
contents are not significantly different between Arabica and Robusta green coffees.
NOMENCLATURE
CGA Total chlorogenic acids
CQAtotal Total caffeoylquinic acids
3-CQA 3-O-Caffeoylquinic acid
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902 BICHO ET AL.
4-CQA 4-O-Caffeoylquinic acid
5-CQA 5-O-Caffeoylquinic acid
diCQAtotal Total dicaffeoylquinic acids
3,4-diCQA 3,4-O-Dicaffeoylquinic acid
3,5-diCQA 3,5-O-Dicaffeoylquinic acid
4,5-diCQA 4,5-O-Dicaffeoylquinic acid
FQAtotal Total feruloylquinic acids
3-FQA 3-O-Feruloylquinic acid
5-FQA 5-O-Feruloylquinic acid
ICO International Coffee Organization.
ACKNOWLEDGMENTS
The authors wish to thank Drs. Joel I. Fahl and Maria Luíza Carelli (IAC) for the supply of
seed material and Professor Dr. Santos Oliveira (FCT/UNL) for his scientific suggestions.
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... g/mL (Yusianto et al., 2007). Acidity of coffee depends on geographical origin, maturity of coffee cherry, drying condition, and postharvest processing (Bicho et al., 2013;Worku et al., 2018). The results show differences in pH level between treatments, i.e. 5.37 (natural), 5.32 (honey), and Bicho et al. (2013) reported that pH of Arabica green bean reached 5.62, and it was affected by the roasting process; longer roasting would produce lower pH, which altered the final taste (Rodriguez et al., 2020). ...
... Acidity of coffee depends on geographical origin, maturity of coffee cherry, drying condition, and postharvest processing (Bicho et al., 2013;Worku et al., 2018). The results show differences in pH level between treatments, i.e. 5.37 (natural), 5.32 (honey), and Bicho et al. (2013) reported that pH of Arabica green bean reached 5.62, and it was affected by the roasting process; longer roasting would produce lower pH, which altered the final taste (Rodriguez et al., 2020). The pH changes result from formation of organic acid during roasting process. ...
... The highest amount of CQAs is found in natural process, reaching up to 5.53 ± 0.12 g/100 g coffee db, while the lowest one occurred in honey process, reaching up to 5.11 ± 0.17 g/100 g coffee db. The results are in line with previous work of Bicho et al. (2013) reporting quantity of 3-CQA, 4-CQA, and 5-CQA in green bean, namely 0.56 g/100 g, 0.71 g/100 g, and 4.43 g/100 g, respectively, with total CQAs of 5.70 g/100 g. In addition, Santiago et al. (2020) reported content of 5-CQA in Arabica green bean reaching 3.47-5.25 ...
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Abstract This work aimed to understand and evaluate the impacts of postharvest procedures on physicochemical characteristics and bioactive compounds (CQAs and alkaloids) of green bean and roasted bean. Arabica green bean of kalosi Enrekang was obtained from different procedures: natural, honey and full-washed, and followed with medium roasting, powdered, and extracted using boiling water. A single-factor ANOVA and t-test was arranged to evaluate data, and OPLS-DA was applied to produce mapping. As the results, full washed processed green beans demonstrated a high lightness, while honey processed green beans showed a high chromaticity a*. Natural processed green beans contained a high CQAs, whereas honey processed green beans contained the highest quantity of alkaloids. In terms of caffeine, natural and honey processed green beans exhibited equal levels. In addition, honey roasted beans contained a high content of 3-CQA and 4-CQA, while full-washed processed roasted beans contained a high level of theobromine. The roasting process was reported to reduce the content of total CQAs and alkaloids.
... The measured pH values of coffee beverages prepared using green beans were 5.6-5.91 within African samples, 5.7 to 5.89 in South American samples, and 5.73 to 5.78 in Central American green coffee beans. These values are in accordance with Bicho et al. (2013). Bicho et al. (2013) also found that coffee chemical composition depends on the geographic origin of the green coffee beans and the post-harvest processing. ...
... These values are in accordance with Bicho et al. (2013). Bicho et al. (2013) also found that coffee chemical composition depends on the geographic origin of the green coffee beans and the post-harvest processing. The acidity of coffee is caused by organic acids such as acetic, formic, malic, citric, and lactic acids, as well as chlorogenic and quinic acids (Bicho et al., 2013;Jeszka-Skowron et al., 2015). ...
... Bicho et al. (2013) also found that coffee chemical composition depends on the geographic origin of the green coffee beans and the post-harvest processing. The acidity of coffee is caused by organic acids such as acetic, formic, malic, citric, and lactic acids, as well as chlorogenic and quinic acids (Bicho et al., 2013;Jeszka-Skowron et al., 2015). Although no significant differences (ANOVA; p ≥ 0.05) were found among the geographical origins in the pH measurements, some differences were observed, and therefore this attribute was later included in the Linear Discriminant Analysis (LDA). ...
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Traceability of geographical origin is a challenging matter for producers and consumers. This research focuses on identifying green Coffea arabica from Africa, South and Central America using volatiles and aqueous-soluble chemical compounds for the first time. Using Linear Discriminant Analysis, we created two models. The first one focused on aqueous soluble compounds and their properties (pH, total antioxidant capacity, total polyphenolic content, caffeine, and chlorogenic acids) showed 91.30% accuracy of identification and, during cross-validation, predicted 82.61% correct identification. The 83.36% of the variability was explained with caffeine and TAC. The second focused on volatiles correctly identifying 100% of testing samples and predicted 86.96% accuracy in cross-validation. 91.17% of the variability between African, South, and Central American coffees was explained based on ketones, aldehydes, organic acids and esters, nitriles, alcohols, and alkenes, while ketones appeared as the strongest parameter among volatiles.
... Additionally, the chlorogenic acids 3-FQA, 4-FQA, 5-FQA, 3,4-diCQA, 3,5-diCQA and 4,5-diCQA were analysed as previously described [31,67]. Samples of 1 g of ground green bean per plant were added to 40 mL of a methanol-water (40:60) solution, stirred for 1 h, and centrifuged (9400× g, 5 min, 20 • C), and the supernatant decanted. ...
... Also, the profile of volatile and non-volatile precursors directly related to coffee aroma/flavour formation vary with plant genetic characteristics, geographical and microenvironment factors, agricultural and post-harvest management practices [38,39,[78][79][80][81]. The contents of several compounds of Gorongosa Mountain beans has fallen within to the ranges previously observed in cropped C. arabica genotypes, namely for caffeine and trigonelline, although somewhat below for total mono CQAs [17,24,31,82]. ...
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Coffea arabica L. is as a tropical crop that can be grown under monocrop or agroforestry (AFS) systems, usually at altitudes greater than 600 m, with suitable environmental conditions to bean quality. This study aimed to assess the effect of altitude (650, 825, and 935 m) and light conditions (deep shade—DS, and moderate shade—MS provided by native trees, and full Sun—FS) on the physical and chemical attributes of green coffee beans produced in the Gorongosa Mountain. Regardless of altitude, light conditions (mainly MS and FS) scarcely affected most of the studied physical and chemical attributes. Among the few exceptions in physical attributes, bean mass tended to lower values under FS in all three altitudes, whereas bean density increased under FS at 650 m. As regards the chemical compound contents, sporadic changes were found. The rises in trigonelline (MS and FS at 935 m), soluble sugars (FS at 935 m), and the decline in p-coumaric acid (MS and FS at 825 m), may indicate an improved sensory profile, but the rise in FQAs (FS at 825 m) could have a negative impact. These results highlight a relevant uncertainty of the quality changes of the obtained bean. Altitude (from 650 to 935 m) extended the fruit maturation period by four weeks, and altered a larger number of bean attributes. Among physical traits, the average sieve (consistent tendency), bean commercial homogeneity, mass, and density increased at 935 m, whereas the bean became less yellowish and brighter at 825 and 935 m (b*, C* colour attributes), pointing to good bean trade quality, usually as compared with beans from 650 m. Furthermore, at 935 m trigonelline and 5-CQA (MS and FS) increased, whereas FQAs and diCQAs isomers declined (in all light conditions). Altogether, these changes likely contributed to improve the sensory cup quality. Caffeine and p-coumaric acid showed mostly inconsistent variations. Overall, light conditions (FS, MS, or DS) did not greatly and consistently altered bean physical and chemical attributes, whereas altitude (likely associated with lower temperature, greater water availability (rainfall/fog), and extended maturation period) was a major driver for bean changes and improved quality.
... There are two main sources of coffee beans of commercial importance, Coffea Arabica and Coffea Robusta (known also as ''Canephora''), which differ in chemical components (Araujo et al., 2021; . Coffee includes valuable chemicals including carbohydrates, lipids, nitrogenous compounds, vitamins, minerals, alkaloids, and phenolic compounds (Bicho et al., 2013;Massoud et al., 2019a). It has been reported that Arabica coffee contains more lipids, while Robusta contains more caffeine and polyphenols (Godos et al., 2014). ...
... According to another study, the chemical parameters like pH, soluble solids and caffeine were measured in Arabica and Robusta green coffees. Their results showed that pH, soluble solids and caffeine in Robusta green coffee were higher than other samples but totally the above parameters in Arabica and Robusta green coffees were not significantly different (Bicho et al., 2013). ...
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... Faded GCB color resulted in a slightly bitter taste with woody or smoky notes [18,47]. GCB packed in GP bags was described as having a medium bright-greenish-bluish coloration as shiny, translucent and fresh [18,47,48]. The color of GCB is related to beverage quality, which strongly suggests that the oxidation process and natural enzymatic biochemical transformation are responsible for coffee flavor and aroma [15]. ...
... greenish-bluish coloration as shiny, translucent and fresh [18,47,48]. The color of GCB is related to beverage quality, which strongly suggests that the oxidation process and natural enzymatic biochemical transformation are responsible for coffee flavor and aroma [15]. ...
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... Consumption of coffee as a stimulant in the broader sense only started circa 1000 AD, when monks Table 1. Features and differences of Coffea Arabica and Coffea Canephora (Badmos, lee, and Kuhnert 2019;Bicho et al. 2013). roast, CGAs are converted into components that contribute to the pigment, flavor and aroma of coffee (Iriondo-DeHond, Iriondo-DeHond, and Del Castillo 2020; Liang and Kitts, 2015). ...
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... Some coffee beans' metabolites, e.g. sugar, caffeine, theobromine, theophylline, trigonelline, and chlorogenic acid, can significantly affect the taste [27,28,29]. Two of them were caffeine and chlorogenic acid [15,16,17]. ...
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The object of this present work was to determine the levels of soluble solids, total acidity and pH in raw and roasted grains of eight cultivars most commonly cultivated in the South of Minas Gerais, and determine the influence of roasting on these parameters. Fruits of Mundo Novo, Topázio, Catuaí Vermelho, Catuaí Amarelo, Acaiá Cerrado, Rubi, Icatu Amarelo and Icatu Amarelo were collected in Fazenda Experimental de São Sebastião do Paraíso da Empresa de Pesquisa Agropecuária de Minas Gerais. The fruits were dry with all the parts creating the known coffee as natural. The toasted grains were obtained by clear roasted, determined visually. The analysis of the results allowed to observe differences in the levels of soluble solids and pH for all the variable studied, in raw and toasted grains. Both cultivars Icatu Amarelo (H 2944) and Acaiá Cerrado presented larger values of the pH in the raw grains and the smallest ones in the toasted grains. The levels of soluble solids were larger in the toasted grains of the cultivars Mundo Novo and Rubi, the smallest values observed for the raw grain were in cultivars Topázio and Rubi. The total acidity showed differences only in toasted grains. There was an increase in the total acidity with the roasting, and reduction in pH values and soluble solids, which showed variation among all cultivars. It was observed that cultivars presented differences in chemical composition, and variations different from this composition with the toasted process.
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Os consumidores estão preocupados em adquirir produtos que atendam as questões ambientais, sociais e conseqüentemente sejam saudáveis, contribuindo para o crescimento da comercialização de produtos orgânicos em todo mundo. O café, produto tradicionalmente cultivado no Brasil e de grande aceitação (70% da população brasileira consome café diariamente), é um dos produtos cultivados sob manejo orgânico. Este trabalho teve por objetivo avaliar as características temporais do gosto amargo na bebida de café orgânico. Foram avaliadas quatro marcas de café orgânico (ORG-1, ORG-2, ORG-3 e ORG-4) e uma marca de café convencional (CON) por meio da Análise Tempo-Intensidade. Sete provadores selecionados e treinados avaliaram as amostras de café utilizando o programa "Sistema de Coleta de Dados Tempo-Intensidade-SCDTI" para Windows. Os resultados obtidos foram estatisticamente analisados por Análise de Variância (ANOVA), teste de Duncan e Análise de Componente Principal (ACP). A marca ORG-3 apresentou maior intensidade máxima (Imax), apresentando diferença estatística significativa (p<0,05) em relação as demais amostras para a percepção desse atributo. Entre as amostras ORG-1, ORG-2, ORG-4 e CON não houve diferença estatística significativa (p>0,05) em relação aos seis parâmetros avaliados.
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Este trabalho teve por objetivo caracterizar seis variedades de C. canephora do Banco de Germoplasma de Café do Instituto Agronômico, em Campinas. Para tanto, considerou-se a caracterização química de quarenta e sete exemplares analisando-se as variáveis sólidos solúveis, lipídios, trigonelina, ácidos clorogênicos e cafeína nas sementes. Observou-se a existência de grande variação entre e dentro dos diferentes materiais analisados, com valores extremos de 24,53% a 30,68% para sólidos solúveis; 6,61% a 12,27% para lipídios; 0,73% a 1,59% para trigonelina; 3,30% a 6,30% para ácidos clorogênicos e 1,94% a 3,29% para cafeína, indicando a possibilidade de seleção de plantas de interesse para o melhoramento dessa espécie.The objective of this work was to characterize six C. canephora varieties from the Coffee Germoplasma Collection of Instituto Agronômico, in Campinas, Brazil. For this a chemical characterization of forthy seven examples was performed. Soluble solids, lipids, trigonelline, chlorogenic acids and caffeine contents were evaluated on seeds. The results demonstrated the occurrance of great variation among and within the analyzed materials, with values ranging from 24,53% to 30,68% for soluble solids; 6,61% to 12,27% for lipids; 0,73% to 1,59% for trigonelline; 3,30% to 6,30% for chlorogenic acids and 1,94% to 3,29% for caffeine. These results indicate the possibility of selection of superior plants for the improvement of the specie.
Chapter
The histology of the coffee bean was established many years ago (Winton and Winton, 1939); however until now, the ultrastructure of this material has not been described. So far we have been unable to find a single printed work at the transmission electron microscope level apart from our own publication (Dentan, 1979). (We apologise to authors whose publications we may have missed in our literature search.) One reason for this lack of interest could be that the cytological and histological studies pose a number of technical problems. The thickness of the cell walls, and the close packing of storage material within the cytoplasm of the coffee bean parenchyma cells do not permit easy fixation, embedding and sectioning. Therefore we include details of how these problems were solved.
Chapter
This chapter summarises the vast literature on the composition* of green coffee beans paying particular attention to those components which are peculiar to coffee. The corresponding data are given for roasted beans and where possible for soluble powders. Attention is focused on compositional factors that might be determinants of acceptability, and situations where the data are incomplete or contradictory with the intention of provoking thought, comment and further investigation.
Thesis
This work was carried out in the laboratories of the “Instituto de Investigação Cientifica e Tropical” (IICT - Portugal), and of the “Unidade de Biotecnologia Ambiental”, of “Faculdade de Ciências e Tecnologia”, of “Universidade Nova de Lisboa” (FCT – UNL, Portugal). Nowadays the production of coffee faces a critical period, due to a related decreasing profit, further correlated to the quality and food safety. Considering the increasing need for protection of public health, in this studies a physical characterization was carried out in five genotypes of parchment coffee “café pergaminho”. It was concluded that these parameters can be used as indicators of quality (commercial and of the drink), as well as of food safety of green coffee. Considering the food is further related with the chemical composition, the levels of caffeine, chlorogenic and hydroxycynamic acids were further analyzed, to evaluate the impact in the drink. The relation between the quality if the coffee and the abiotic stress faced by the coffee plants in the tropical zones it has been known. Accordingly, some aclimatation parameters of oxidative stress under high irradiation and low temperature (4 ºC) were further characterized in five genotypes. https://opac.fct.unl.pt/cgi-bin/koha/opac-search.pl?q=ccl=au:Natalina%20da%20Concei%C3%A7%C3%A3o%20Cavaco%20Bicho&sort_by=relevance_dsc&limit=au:Bicho,%20Natalina%20da%20Concei%C3%A7%C3%A3o%20Cavaco
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1 A History of Coffee.- 2 Botanical Classification of Coffee.- 3 Coffee Selection and Breeding.- 4 Climate and Soil.- 5 Physiology of the Coffee Crop.- 6 Mineral Nutrition and Fertiliser Needs.- 7 Cultural Methods.- 8 Pest Control.- 9 Control of Coffee Diseases.- 10 Green Coffee Processing.- 11 World Coffee Trade.- 12 The Microscopic Structure of the Coffee Bean.- 13 Chemical and Physical Aspects of Green Coffee and Coffee Products.- 14 The Technology of Converting Green Coffee into the Beverage.- 15 The Physiological Effects of Coffee Consumption.