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Coffee, one of the most popular beverages in the world, contains many bioactive compounds. The aim of this study was a comparative evaluation of the content of bioactive compounds in organic and conventional coffee (Coffea arabica) originating from Brazil during 12 months storage. The content of the polyphenolic compounds was determined using HPLC analysis. The obtained results indicate that organic or conventional production and roasting conditions (light, medium, dark roast) affect the polyphenolic compounds of coffee. The highest content of total polyphenolic compounds was determined in coffees roasted in light and medium roasting conditions. Furthermore, organic coffee beans showed higher content of bioactive compounds (total phenolic, phenolic acids and flavonoids) than conventional coffee beans. During 12 months storage a decrease in polyphenolic compounds is observed and it is connected with the degradation of chlorogenic acid, which influences total bioactivity. Moreover, the highest caffeine content was observed in light and medium roasted coffee and after storage an increase in caffeine content was observed only in organic coffee beans.
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European Food Research and Technology (2020) 246:33–39
https://doi.org/10.1007/s00217-019-03388-9
ORIGINAL PAPER
The content ofpolyphenols incoee beans asroasting, origin
andstorage eect
KatarzynaKról1 · MagdalenaGantner1· AleksandraTatarak1· EwelinaHallmann1
Received: 18 July 2019 / Revised: 10 October 2019 / Accepted: 12 October 2019 / Published online: 6 November 2019
© The Author(s) 2019
Abstract
Coffee, one of the most popular beverages in the world, contains many bioactive compounds. The aim of this study was a
comparative evaluation of the content of bioactive compounds in organic and conventional coffee (Coffea arabica) originating
from Brazil during 12months storage. The content of the polyphenolic compounds was determined using HPLC analysis.
The obtained results indicate that organic or conventional production and roasting conditions (light, medium, dark roast)
affect the polyphenolic compounds of coffee. The highest content of total polyphenolic compounds was determined in cof-
fees roasted in light and medium roasting conditions. Furthermore, organic coffee beans showed higher content of bioactive
compounds (total phenolic, phenolic acids and flavonoids) than conventional coffee beans. During 12months storage a
decrease in polyphenolic compounds is observed and it is connected with the degradation of chlorogenic acid, which influ-
ences total bioactivity. Moreover, the highest caffeine content was observed in light and medium roasted coffee and after
storage an increase in caffeine content was observed only in organic coffee beans.
Keywords Organic farming· Arabica· Bioactive compounds· Storage· Caffeine· Chlorogenic acid
Introduction
The most widely cultivated species are Coffea arabica
(Arabica) and Coffea canephora (Robusta). Despite the
poorer sensory quality of Robusta, it has the advantage of
allowing the extraction of large amounts of soluble solids,
which enables its use in blends and the soluble coffee indus-
try [1]. The coffee beverage is a rich source of bioactive
compounds especially polyphenols, such as phenolic acids,
mostly chlorogenic (in green beans) and caffeic (occur-
ring after roasting). Other phenolic acids in coffee beans
are: ferulic and p-coumaric. These compounds contribute
to the total polyphenol intake in diet and are beneficial to
consumer health [2, 3]. Coffee is the main source of chloro-
genic acid in human diet and has been cited as an efficient
invitro and exvivo antioxidant [4]. The consumption of
coffee can reduce cancers such as colon [5] and oral cancer
[6], diabetes, liver disease, inhibits the oxidation of LDL
cholesterol, protects against Parkinson’s disease and even
reduces mortality risk [7, 8]. The profile and content of bio-
active compounds depend mainly on roasting parameters,
which range from 160 to 240°C and from 8 to 24min. The
colour of beans is a main parameter to describe a degree of
roasting and is classified as light, medium and dark roasted
coffee [8]. During the roasting process, a decrease in poly-
phenolic compounds is observed and it is connected with
the degradation of chlorogenic, malic and citric acid, which
influences the total antioxidant activity. However, the for-
mation of melanoidins and quinic acid during thermal pro-
cess can maintain or even enhance the antioxidant capacity
[912]. The lighter roasted coffee had the highest antioxidant
activity compared to dark roasted coffee and also unroasted
coffee [13]. The origin, harvesting, processing, and prepara-
tion of the beverage influence the total antioxidant activity
[14]. Recently, organic food has gained higher popularity
due to a demand for healthy foods and production methods.
The strict rules of organic coffee production without
mineral fertilizers and pesticides give a higher food safety
and quality [15]. On the other hand, plants produced under
organic conditions synthetize more phenolic compounds as
an effect of “self-protection” [16]. Polyphenols compounds
are well known as natural pesticides for plants [17]. For
* Magdalena Gantner
magdalena_gantner@sggw.pl
1 Department ofFunctional andOrganic Food, Institute
ofHuman Nutrition, Warsaw University Life ofSciences,
159c Nowoursynowska Str., 02-776Warsaw, Poland
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34 European Food Research and Technology (2020) 246:33–39
1 3
human health polyphenols are strong antioxidants and pro-
tect against many non-infection diseases [18]. The effect of
coffee brewing, grinding, origin, and roasting process on
bioactive compounds has been widely studied [1921] but
there is a lack of studies concerning organic coffee produc-
tion and its influence on the bioactive compounds in cof-
fee. Therefore, this study aimed to determine the content
of bioactive compounds of Coffee arabica originating from
Brazilian region from organic and conventional production
under varied roasting conditions (light, medium, and dark
roasted beans).
Material andmethod
Material preparation, roasting parameters, storage
condition
Green coffee beans were imported from Brazil, organic plan-
tation was located near Coronel Fabriciano, Minas Gerias
region (19o51S 42o62E). Conventional farm was located
very near to organic (19° 55 S 42° 68 E). The amount of
sample was 2kg per combination. In Poland green coffee
samples were subjected to roasting under the following con-
ditions: light level: 190°C, roasting time: 25min; medium
level: 220°C, roasting time: 25min; dark level: 250°C,
roasting time: 25min. The coffee roasting equipment was:
rotary oven barrel with 8kg of coffee beans beaching (Spo-
Masz, Poland). After the roasting process, the coffee beans
were vacuum-packed and brought to the laboratory for
chemical analyses. One sample was divided into two groups:
for “fresh analysis” just after roasting process and for “stor-
age”. Storage conditions: coffee samples in vacuum bags
were stored in the following conditions: temperature 5°C,
time 12months.
Dry matter
Dry matter content was measured using the scale method
(PN-EN 12145:2001) [22]. Summary: the mass of an
empty glass beaker was measured on the laboratory scale.
In the next step, 2g of milled coffee beans was placed into
a beaker, and the mass was weighted again. After 24h of
drying at a temperature 105°C, the samples were cooled
(21°C) and weighed for the third time. Based on mass differ-
ence, the content of the total dry matter in examined samples
was calculated. The results are expressed as g per 100g−1of
product.
Polyphenols andcaeine
Polyphenols were measured using the high-performance liq-
uid chromatography (HPLC) method [23]. Before analysis,
samples were ground in a coffee mill (Bosh, Germany,
MKM6003), to obtain a mean particle size of 495μm. One
gram of milled coffee beans was extracted in 100ml of hot
(boiled) deionized water. After 6min, coffee extracts were
filtrated using a paper filter to a 250ml breaker. 1ml of
filtered coffee was transferred to HPLC-vials and used for
examination. For analysis purposes, HPLC-set-ups were
used: two LC-20AD pumps, a CMB-20A system control-
ler, a SIL-20AC autosampler, an ultraviolet–visible SPD-
20AV detector, a CTD-20AC oven, and a Phenomenex
Fusion-RP 80A column (250 × 4.60mm), all from Shimadzu
(Shimadzu, Tokyo, Japan). The gradient mobile phase con-
tained 10% (phase A) and 55% (phase B) of acetonitrile and
deionized water. After the mixing of acetonitrile and water
in appropriate proportions, orthophosphoric (85%) acid was
added and the pH of the solution was measured simultane-
ously. After obtaining a stable value (3.0), the phases were
ready to flow: 1mlmin−1, time program: 1.00–22.99min-
phase A 95% and 5% phase B, 23.00–27.99min-phase A
50% and 50% phase B, 28.00–28.99-min phase A 80% and
20% phase B, 29.00–38.00-min phase A 95% and 5% phase
B. The wavelengths used for detection were 250nm for
flavonoids and caffeine (quercetin-3-O-rutinoside, kaemp-
ferol-3-O-glucoside, myricetin, quercetin, quercetin-3-O-
glucoside, apigenin, kaempferol) and 370nm for phenolic
acids (gallic, chlorogenic, caffeic, p-coumaric, ferulic). The
phenolic compounds (quercetin-3-O-rutinoside, kaemp-
ferol-3-O-glucoside, myricetin, quercetin, quercetin-3-O-
glucoside, apigenin, kaempferol, gallic, chlorogenic, caf-
feic, p-coumaric, ferulic) were identified based on Fluka and
Sigma Aldrich (Poland) external standards with a purity of
99.5%.
Statistical analysis
The obtained results were statistically elaborated with
Statgraphics® Centurion 15.2.11.0 software (StatPoint Tech-
nologies, Inc., Warranton, VA, USA). Two-way ANOVA
analysis was used. The factors within the experiment were
the method of production (organic or conventional) and the
level of bean roasting (light, medium, dark). The number
of samples per system of production was n = 18, and the
number of samples per bean roasting was n = 6, separately
before and after storage. The lack of statistical differences
(p > 0.05) is described in tables as not significant (NS). Dif-
ferent letters within a row indicate statistical differences on
the level (p < 0.05).To obtain a clearer picture of the interre-
lations between the identified biologically active compounds
and the level of bean roasting stage, an analysis of the main
component (PCA) was used. A principal component analysis
(PCA) is a handy statistical tool that applies an orthogonal
transformation to convert a set of data of possibly corre-
lated variables into a set of values of linearly uncorrelated
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35European Food Research and Technology (2020) 246:33–39
1 3
variables called principal components. The PCA figures
were made using Statistica 10.0 (Statsoft, Tulsa, USA). The
PCA was conducted on the basis of the correlation matrix,
not the covariance matrix, which corresponds to the analysis
of standardized data.
Results anddiscussion
Dry weight
The main bioactive compounds and dry matter of fresh
and stored coffee beans (C. arabica) are shown in Tables1
and 2. The initial dry weight during storage was 97.56 and
97.94g 100g−1 for fresh organic and conventional beans and
after storage it was 96.44 and 96.78g 100g−1, respectively.
Furthermore, the roasting degrees have a significant effect
on the dry weight of beans, mainly the highest content has
dark roasted coffee (98.74g 100g−1) while the smallest in
light roasted (96.24g 100g−1). These results are in close
agreement with obtained results for Brazil beans reported
by Dybkowska etal. [24].
Caeine
The results of descriptive statistics showed that coffee
beans from organic and conventional farming are different
by caffeine content. Conventional coffee contained signifi-
cantly more caffeine compared to organic one (Table1). In
conventional growing system, nitrogen fertilizer is widely
used. Caffeine is purine alkaloid and nitrogen fertilization
can increase the level of that alkaloid in coffee beans [25].
Not only dose but as well kind of nitrogen fertilizer could
increase the level of caffeine. The easily soluble nitrogen
used in conventional growing system gives an effect of caf-
feine increasing compare to organic one. Information about
caffeine content and changes during storage in organic cof-
fee beans is highly limited in literature; however, the higher
content of caffeine in organic coffee is connected with fer-
tilization methods, mainly organic coffee, in organic farm-
ingsystems, the useof pesticidesandsynthetic fertilizers
is completely forbidden. For pest management, caffeine
(alkaloid) is a “natural pesticide” plants produce in this
case, which helps toprotectthem against insects [26]. Fur-
thermore, this is not surprising as coffee bean caffeine and
other polyphenols content may not only be influenced by
geographical location and soil physico-chemical properties,
but also by bean variety, environmental factors (climate) [27]
and agricultural practices (organic vs. conventional farming)
[28]. During storage, the significant increase of caffeine in
organic coffee was observed, to 8.55mgg−1 and non-sig-
nificant increase to 5.41mgg−1 in conventional one. The
amount of caffeine in organic stored coffee was much higher
than in conventional coffee beans. The quantity of caffeine
was significantly affected by the roasting degree and light
roasted coffee (6.42mgg−1) presented higher caffeine levels
than medium (5.77mgg−1) and dark roasted (2.63mgg−1)
beans. The same trend was observed for coffee beans stored
Table 1 Chemical properties of coffee from organic and conventional production (average value ± standard deviation) for freshly roasted and
stored coffee beans
N.S. not significant statistically
*Values followed by different small letters in the same row are significantly different (p < 0.05)
Chemical parameters Organic coffee Conventional coffee p value
Freshly roasted Stored Freshly roasted Stored Freshly roasted Stored
Dry matter (g 100g−1)97.56 ± 1.47a,*96.44 ± 1.14a97.94 ± 1.44a96.78 ± 1.12aN.S. N.S.
Caffeine (mgg−1)4.61 ± 1.69b8.55 ± 3.45b5.26 ± 1.97a5.41 ± 2.32a0.0077 < 0.0001
Total polyphenols (mgg−1)8.95 ± 0.77a1.41 ± 0.17a8.28 ± 1.16b1.49 ± 0.47a0.0023 N.S.
Total phenolic acids (mgg−1)7.60 ± 0.92a0.78 ± 0.07a7.34 ± 1.24a0.52 ± 0.20bN.S. < 0.0001
Gallic (mgg−1)1.45 ± 1.00a0.59 ± 0.085a1.17 ± 0.57b0.38 ± 0.19b0.0012 0.0001
Chlorogenic (mgg−1)5.94 ± 1.45a0.02 ± 0.01a6.00 ± 1.83a0.02 ± 0.01aN.S. N.S.
Caffeic (mgg−1)0.058 ± 0.07a0.15 ± 0.03a0.050 ± 0.07b0.11 ± 0.05b0.0065 < 0.0001
Salicylic (mgg−1)0.158 ± 0.57a0.03 ± 0.01a0.121 ± 0.16a0.003 ± 0.001b0.0013 < 0.0001
Total flavonoids (mgg−1)1.35 ± 0.05a0.63 ± 0.12b0.94 ± 0.06b0.97 ± 0.41a< 0.0001 < 0.0001
Epigallocatechin gallate (mgg−1)0.59 ± 0.38a0.45 ± 0.012a0.28 ± 0.19b0.57 ± 0.18a< 0.0001 0.0001
Quercetin-3-O-rutinoside (mgg−1)0.103 ± 0.06b0.02 ± 0.02a0.156 ± 0.06a0.02 ± 0.01a0.0001 N.S.
Quercetin-3-O-glucoside (mgg−1)0.062 ± 0.01a0.003 ± 0.001b0.028 ± 0.01b0.04 ± 0.001a< 0.0001 < 0.0001
Kaempferol-3-O-glucoside (mgg−1)0.34 ± 0.07a0.13 ± 0.29b0.35 ± 0.15a0.29 ± 0.29aN.S. < 0.0001
Quercetin (mgg−1)0.11 ± 0.06a0.03 ± 0.02b0.07 ± 0.03b0.02 ± 0.02a0.0062 0.0135
Kaempferol (mgg−1)0.14 ± 0.02a0.002 ± 0.001b0.06 ± 0.04b0.03 ± 0.04a< 0.0001 < 0.0001
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36 European Food Research and Technology (2020) 246:33–39
1 3
for 12months. The results obtained by Tfouni etal. [20],
Jeon etal. [29], Clarke etal. [30] showed that caffeine con-
tent is not affected by roasting degree. However, our results
are in close agreement with the ones obtained by Hecimovic
etal. [21] and Wanyika etal. [31], where dark roasted coffee
has less caffeine than lighter roasts. Similar results of the
increase in caffeine content during storage were obtained
for tea samples. The explanation of these results could be
the degradation of complex theaflavins and caffeine in the
storage, which resulted in the dissociation and detection of
caffeine [32].
Total polyphenols
According to the data shown in Tables1 and 2 the culti-
vation method, roasting degree, and storage have a sig-
nificant effect on the total polyphenols content in coffee
beans. Organic coffee beans showed a higher content of
total phenolic content (8.95mgg−1) than conventional one
(8.28mgg−1). After 12months of storage, the significant
decrease in polyphenols was observed, 83.4% for organic
coffee, and 82.9% for conventional one. Furthermore, no
significant differences between conventional (1.49mgg−1)
and organic (1.41mgg−1) beans were recorded. The
content of polyphenols was significantly affected by the
intensity of the roasting process and the highest content
was observed for fresh light-roasted beans 8.74mgg−1,
while the lowest for medium roasted 7.95mgg−1. In
stored beans, the results showed that the highest content
was for light roasted, and the lowest in dark roasted, 1.58
and 1.17mgg−1, respectively. The presented results con-
firmed that the content of polyphenols may be related to
the cultivation method as well as to the origin of the coffee
[12]. Our results are consistent with previous reports [12,
21, 24], wherewith increasing the degrees of roasting, the
polyphenols content became considerably reduced. Kat-
sube etal. [33] mentioned that polyphenolic compounds
are highly thermolabile compounds that easily decompose
under the effect of high temperature (above 80°C). This
reduction is a result of the thermal instability during roast-
ing of polyphenolic compounds and their degradation [1,
12, 21, 34]. However, the polyphenol loss is undesirable
for consumers due to beneficial effects for health.
Table 2 Chemical properties of coffee beans depending on roasting level and storage time (average value ± standard deviation)
N.S. not significant statistically
*Values followed by different small letters in the same row are significantly different (p < 0.05)
Chemical param-
eters
Light Medium Dark p value
Freshly roasted Stored Freshly roasted Stored Freshly roasted Stored Freshly roasted Stored
Dry matter (g
100g−1)
96.24 ± 0.87b*96.97 ± 0.83a98.28 ± 1.04a95.89 ± 0.67a98.74 ± 0.91a96.98 ± 0.92a0.0005 N.S.
Caffeine (mgg−1)6.42 ± 0.22a8.75 ± 0.35a5.77 ± 1.13b7.93 ± 0.13b2.63 ± 0.11c4.26 ± 1.03c< 0.0001 < 0.0001
Total polyphenols
(mgg−1)
9.45 ± 0.51a1.58 ± 0.03a7.95 ± 0.18c1.60 ± 0.10a8.44 ± 1.35b1.17 ± 0.33b< 0.0001 < 0.0001
Total phenolics
acids (mgg−1)
8.74 ± 0.46a0.59 ± 0.01b6.65 ± 0.25c0.79 ± 0.09a7.03 ± 0.81b0.57 ± 0.24b< 0.0001 0.0006
Gallic (mgg−1)0.66 ± 0.05b0.40 ± 0.00b0.94 ± 0.10b0.63 ± 0.00a2.33 ± 0.50a0.42 ± 0.18b< 0.0001 0.0003
Chlorogenic
(mgg−1)
8.00 ± 0.46a0.02 ± 0.00b5.56 ± 0.46b0.02 ± 0.00b4.35 ± 0.37c0.03 ± 0.00a< 0.0001 0.0004
Caffeic (mgg−1)0.007 ± 0.00a0.16 ± 0.00a0.009 ± 0.00a0.12 ± 0.02b0.146 ± 0.01a0.11 ± 0.07bN.S. < 0.0001
Salicylic (mgg−1)0.073 ± 0.03c0.02 ± 0.00a0.140 ± 0.03b0.02 ± 0.07a0.204 ± 0.02a0.01 ± 0.00b< 0.0001 < 0.0001
Total flavonoids
(mgg−1)
0.71 ± 0.09b1.00 ± 0.03a1.31 ± 0.09a0.81 ± 0.05b1.41 ± 0.56a0.61 ± 0.10c< 0.0001 < 0.0001
Epigallocatechin
gallate (mgg−1)
0.08 ± 0.00b0.52 ± 0.03ab 0.64 ± 0.18a0.60 ± 0.00a0.57 ± 0.35a0.42 ± 0.11b< 0.0001 < 0.0001
Quercetin-3-O-ruti-
noside (mgg−1)
0.053 ± 0.03b0.02 ± 0.00b0.155 ± 0.06a0.02 ± 0.00b0.180 ± 0.02a0.03 ± 0.01a< 0.0001 < 0.0001
Quercetin-3-O-glu-
coside (mgg−1)
0.041 ± 0.02b0.02 ± 0.00a0.049 ± 0.00a0.02 ± 0.02a0.046 ± 0.04a0.02 ± 0.01a0.0249 N.S.
Kaempferol-3-O-
glucoside (mgg−1)
0.47 ± 0.09a0.43 ± 0.01a0.31 ± 0.09b0.14 ± 0.02b0.26 ± 0.03c0.06 ± 0.04b< 0.0001 < 0.0001
Quercetin (mgg−1)0.04 ± 0.00b0.01 ± 0.00b0.11 ± 0.00a0.03 ± 0.02a0.13 ± 0.05a0.03 ± 0.01a< 0.0001 < 0.0001
Kaempferol
(mgg−1)
0.03 ± 0.01b0.002 ± 0.00b0.04 ± 0.00b0.01 ± 0.001a0.22 ± 0.13a0.04 ± 0.004a< 0.0001 < 0.0001
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37European Food Research and Technology (2020) 246:33–39
1 3
Phenolic acids
The total content of phenolic acids for fresh beans was
higher in organic coffee (7.60mgg−1) than in conven-
tional beans (7.34mgg−1), although this difference was
not significant. After 12months of storage, the signifi-
cant loss of phenolic acids was observed, and the loss
for organic was 90%, for conventional 93%, respectively.
The level of phenolic acids was the highest in the light-
roasted coffee, while after storage for medium roasted.
The content of gallic acid was significantly higher in
organic coffee (30%). Furthermore, during roasting pro-
cess, the content of gallic acid was higher, which was
connected with the decomposition of chlorogenic acid.
A similar trend was observed for caffeic and salicylic
acids. The chlorogenic acids (CGA), which are known
for their antioxidant capacities, are the main components
of the phenolic fraction of coffee beans. CGA is an ester
formed between caffeic acid and quinic acid and is hydro-
lyzed into various aromatic acid metabolites including
caffeic and salicylic acid [25, 35]. The initial content of
chlorogenic acid was for organic coffee and conventional
5.94mgg−1 and 6.00mgg−1, respectively. During roast-
ing, the levels of CGA decreased considerably, whereas
the levels of caffeic and salicylic acid increased during
the roasting process (p < 0.0001). The highest content was
for the lightly roasted beans 8.00mgg−1 and the smallest
for the dark-roasted beans 4.35mgg−1. Furthermore, Wei
and Tanokura [36] investigated, that the decomposition of
chlorogenic acids could be used as an index of roasting
degree what is in close agreement with results obtained in
this study. During 12months of storage, the loss of CGA
was observed and was on the same level (0.02mgg−1).
The decrease in CGA occurred due to enzymatic and non-
enzymatic oxidation. The non-enzymatic oxidation is due
to the participation reaction between enzymes (monophe-
nolase, o-diphenolase, and laccase) and chlorogenic acid
[37]. This is in line with the literature as high temperature
during the roasting process and storage results in the loss
of chlorogenic acid content, and the increase in caffeic,
salicylic and gallic acid [3, 21, 34, 36, 38]. In relation
to geographical origin of coffee beans, it was found that
total CGA contents of Arabica green coffee beans grown
in different parts of Kenya varied considerably [39]. Simi-
lar results obtained by Bertrand etal. [40] also reported
variation in the concentrations of CGA in green beans
grown in different regions of Colombia. The differences
found between organic and conventional coffee are not
only due to the different farming method, but also cof-
fees cultivated in similar regions of the same country are
genetically diverse [41].
Total avonoids
While caffeine and CGAs represent the main components
found in coffee beans, a variety of flavonoids have also been
identified; however, in lower concentration. The obtained
results showed that organic coffee has a significantly higher
content (p < 0.0001) of flavonoids than conventional cof-
fee beans. Furthermore, the flavonoid content of coffee was
significantly (p < 0.0001) affected by the roasting degree
and the higher content was observed in dark roasted beans
(1.41mgg−1). The storage time had no significant effect on
the flavonoid content. However, in organic coffee beans the
53% reduction of total flavonoid was observed, in contrast
to the conventional ones, where the content was on the same
level. These observations are in agreement with the results
previously obtained by Hecimovic [21] and Odžakovic etal.
[42], which confirmed that the highest flavonoid content is
in dark roasted coffee whereas the other varieties were more
beneficial in light and medium roasted coffee. Otherwise,
Hudakova etal. [43] reported highest content of flavonoids
in unroasted coffee Arabica. In a study conducted by Lee
etal. [18] it has been found that the sample roasted at lowest
temperature exhibited highest total flavonoids content. Fur-
thermore, the epigallocatechin gallate was the most abun-
dant flavonoid in organic and conventional beans, showed
the smallest decrease in the content and decrease during
storage was observed only for organic coffee (p < 0.0001).
The decrease in flavonoids content during storage was
observed in the case of rutinoside-3-O-quercetin, glycoside-
3-O-kaempferol,glycoside-3-O-quercetin, quercetin, and
kaempferol for every type of coffee bean. The decrease in
flavonoids content suggests that it acted as an antioxidant,
minimizing protein and lipid oxidation. Flavonoids content
has also been investigated by Getachew and Chun [44], Kre-
icbergs etal. [45], where quercetin, catechin and kaempferol
and their derivatives were the most abundant in coffee bean
samples, what is in line with obtained results.
PCA
A principal component analysis (PCA) was performed to
explain the differences between the samples of coffees in
terms of storage time, roasting degree of organic and con-
ventional coffee beans (Fig.1). The corresponding score
plot showed that the first two components describe 79.51%
of the initial variability. The values of 58.71% data vari-
ance explained by the horizontal axis and 20.80% inter-
cepted by the vertical axis, indicate that it is much more
significant along the abscissa axis than along the ordinate
axis. The variables on the plot showed that it is possible to
group the samples according to storage time, fresh coffee
beans have a positive value along the horizontal axis, while
stored negative. Furthermore, for stored samples no clear
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38 European Food Research and Technology (2020) 246:33–39
1 3
distinct clusters were obtained (among light-, medium-, and
dark-roasted beans). They present the smallest diversity of
variation from tested samples. However, conventional coffee
beans were in the same area, thus, they had a more similar
profile of bioactive compounds, than the organic coffee. In
the case of fresh beans, a very effective separation between
roasting degrees was observed. Light-roasted organic and
conventional beans were positive along vertical and hori-
zontal axes. Medium-roasted organic coffee showed a posi-
tive value along ordinate axis. The biggest variety in the
tested group was noted for fresh dark-roasted beans, results
were positive along ordinate axis and negative values were
obtained along abscissa axis, which was also confirmed by
the analysis of bioactive compounds described previously.
Conclusion
The obtained results indicate that coffee origin (organic or
conventional) affects the polyphenolic compounds of coffee.
The second hypothesis was as well confirmed. The light and
medium roasting are more beneficial for preserving bioac-
tive compounds. The quantity of caffeine was significantly
affected by the roasting level. We observed, that only light
roasted coffee presented the highest caffeine content. In
light- and medium-roasted coffee, the content of chloro-
genic acid was the highest and the smallest of chlorogenic
acid derivatives. Whereas, in dark-roasted coffee flavonoids
were the most abundant compounds. Fresh organic coffee
beans showed a higher content of total phenolic, phenolic
acids as well as flavonoids than conventional coffee beans.
For the conventional beans after 12 of months storage the
loss of bioactive compounds was observed and the smallest
decrease in concentration was observed for epigallocatechin
gallate. During the storage time, significant increase in caf-
feine in organic coffee was observed.
Acknowledgements This paper has been published under the support
of: Polish Ministry of Higher Education within founds of Institute of
Human Nutrition, Warsaw University of Life Sciences (WULS), for
scientific research.
Compliance with ethical standards
Conflict of interest The authors declare that they have no conflict of
interest.
Compliance with ethics requirements This article does not contain
any studies with human or animal subjects.
Open Access This article is distributed under the terms of the Crea-
tive Commons Attribution 4.0 International License (http://creat iveco
mmons .org/licen ses/by/4.0/), which permits unrestricted use, distribu-
tion, and reproduction in any medium, provided you give appropriate
credit to the original author(s) and the source, provide a link to the
Creative Commons license, and indicate if changes were made.
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... Antioxidative capacity of roasted coffee is associated with the degradation of green coffee bioactive compounds particularly polyphenols, such as phenolic acids, mainly chlorogenic acid into caffeic acid, gallic acid, quinic acid, etc., and the formation of some compounds particularly melanoidins (Król et al., 2019;Mehaya & Mohammad, 2020;Pérez-Hernández et al., 2012;Yashin et al., 2013). ...
... CGA is an ester formed between caffeic acid and quinic acid (Cano-Marquina et al., 2013;Król et al., 2019) and is hydrolyzed by the intestinal microflora into various aromatic acid metabolites including caffeic acid and salicylic acid (Farah & Donangelo, 2006;Flament, 2001;Itagaki et al., 2011;Król et al., 2019;Olthof et al., 2001). CGA takes part in the formation of color, flavor, and aroma during roasting. ...
... CGA is an ester formed between caffeic acid and quinic acid (Cano-Marquina et al., 2013;Król et al., 2019) and is hydrolyzed by the intestinal microflora into various aromatic acid metabolites including caffeic acid and salicylic acid (Farah & Donangelo, 2006;Flament, 2001;Itagaki et al., 2011;Król et al., 2019;Olthof et al., 2001). CGA takes part in the formation of color, flavor, and aroma during roasting. ...
... There are two analytical approaches to assessing the antioxidant status of a sample in vitro: (1) measuring the concentration of single antioxidants and (2) evaluating their integral content [11]. By using high-performance liquid chromatography, it was shown that the antioxidant properties of coffee are attributed to phenolic compounds [12][13][14], tocopherols [8,15] and ascorbic acid [15]. The main contribution falls on phenolic antioxidants, which are represented by phenolic acids (chlorogenic, gallic, caffeic, syringic, ferulic, etc.), flavonoids (quercetin, catechin, epigallocatechin gallate, kaempferol, resveratrol, etc.) and their derivatives (glucosides, esters, etc.) [12][13][14]. ...
... By using high-performance liquid chromatography, it was shown that the antioxidant properties of coffee are attributed to phenolic compounds [12][13][14], tocopherols [8,15] and ascorbic acid [15]. The main contribution falls on phenolic antioxidants, which are represented by phenolic acids (chlorogenic, gallic, caffeic, syringic, ferulic, etc.), flavonoids (quercetin, catechin, epigallocatechin gallate, kaempferol, resveratrol, etc.) and their derivatives (glucosides, esters, etc.) [12][13][14]. The second approach, based on the use of the methods for determining antioxidant activity/capacity (AOA/AOC), is less labor-intensive and enables measuring synergistic and antagonistic antioxidant effects and considering the effect of unknown (rare) antioxidant compounds. ...
... At the same time, the chemical composition of coffee changes during roasting in a complex way, which results from the Maillard reaction, pyrolysis and caramelization [5], accompanied by a release of volatile compounds [23]. In general, the data on the effect of roasting on phenolic antioxidants and AOA of coffee are inconsistent [5,6,12,13,19,[24][25][26]. With an increase in roasting degree, the content of phenolic compounds in coffee can increase, decrease and change in different directions [12,13,24]; however, convincing evidence that roasting causes a lower concentration of chlorogenic acids was suggested in [13,24,25,27]. ...
Article
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Thermal and non-thermal technologies used in food processing should be not only effective in terms of decontamination and preservation but also minimize undesirable losses of natural bioactive compounds. Arabica (Coffea arabica) is the most cultivated variety of coffee, making it a valuable source of phytonutrients, including antioxidants. In the present study, green and roasted Arabica coffee beans were treated with slow freezing (SF), fast freezing (FF), microwave radiation (MWR) and cold atmospheric plasma (CAP). Moisture content (MC) of coffee beans and antioxidant activity (AOA) of aqueous extracts were measured. Green coffee showed a decrease in MC after MWR treatment, and roasted coffee showed an increase in MC after freezing. After SF and FF at −19 °C for 24 h, all extract samples showed an increase in AOA by 4.1–17.2%. MWR treatment at 800 W for 60 s was accompanied by an increase in the AOA of green coffee extracts by 5.7%, while the changes in the AOA of roasted coffee extracts were insignificant. Sequential combined treatments of SF + MWR and FF + MWR resulted in an additive/synergistic increase in the AOA of green/roasted coffee extracts, up to +23.0%. After CAP treatment with dielectric barrier discharge (DBD) parameters of 1 μs, 15 kV and 200 Hz for 5 and 15 min, green coffee showed a decrease in the extract AOA by 3.8% and 9.7%, respectively, while the changes in the AOA of roasted coffee extracts were insignificant. A high positive correlation (r = 0.89, p < 0.001) between AOA and MC was revealed. The results obtained indicate that SF, FF, MWR and combined treatments may be applied at the pre-extraction stage of coffee bean preparation in order to increase the yield of antioxidant extractives.
... Chlorogenic acid (3-O-caffeoylquinic acid) and its isomer 5-caffeoylquinic acid are widely regarded as the main phenolic constituents in coffee; their degradation during roasting operation contributes to the roasted coffee's final flavour, and the level of their decomposition is often used as a parameter to assess the roasting degree. Besides, the degradation of chlorogenic acids over roasting by up to 90% observed in the current study is consistent with other reported results (Król, Gantner, Tatarak, & Hallmann, 2020;Vignoli, Viegas, Bassoli, & Benassi, 2014). Furthermore, since chlorogenic acid is an ester of caffeic and quinic acids and, upon degradation, produces various metabolites, including caffeic and salicylic acids; therefore, it is not surprising to see a significantly higher concentration of caffeic acid in roasted samples and its Table 1 Physicochemical parameters, total phenolic content (TPC), total flavonoids content (TFC) and caffeine content of coffee and baobab brews. ...
... However, this depends mainly on the species and their origin (Hečimović et al., 2011). It is worth noting that while phenolic acids and their derivatives were the main phenolics in coffee beans, several flavonoids were also identified, although in low concentrations consistent with previous results (Król et al., 2020). On the other hand, baobab seeds were rich in phenolic acid derivatives, such as cinnamic and caffeic acids and flavonoids, including quercetin and catechin Salih & Yahia, 2015). ...
Article
The seeds of Africa's majestic baobab are often discarded or poorly utilized. Few studies explored its potential as a coffee substitute, while the key volatile compounds are still unknown. These compounds were hypothesized to be responsible for baobab's sensory acceptance. In this study, the physicochemical, sensory, and key volatile composition of brews from coffee beans and baobab seeds subjected to different roasting conditions were reported. Roasting increases pH while reducing acidity, total soluble solids, lightness (L*), redness/greenness (a*), and yellowness/blueness (b*) in coffee and baobab brews. Phenolic contents increased significantly (p < 0.05) with increased roasting intensity in baobab while degrading in coffee. Significant variability of volatile composition existed among coffee and baobab matrices and the roasting conditions. Nevertheless, the presence of several key coffee odorants in baobab from pyrazines, phenols, and furans chemical families, owing to their odour active value ≥1, likely contributed to its sensory acceptance.
... In another study, Górecki, Hallmann [6] informed that coffee brewed for 3 min showed lower amounts of total flavonoid than 6 min of brewing, which was similar to Brazil coffee brew and contrary to Colombia and Peru coffee brews. Additionally, Król et al. [23] reported that total flavonoid content of roasted (190 °C for 25 min) coffee beans was 0.71 mg/g. ...
... mg/100 ml) and quercetin (0.86-0.87 mg/100 ml). In another study, Krol et al. [23] obtained lower quercetin (0.07 mg/g) and kaempferol (0.06 mg/g) content, higher gallic acid amount (1.17 mg/g), and similar caffeic acid content (0.05 mg/g) in roasted coffee beans as compared with those of the current study. ...
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This study was performed to compare the effects of brewing method (decoction and infusion), time (1–5 min), and also origin of coffee beans on antioxidant activity using DPPH, ABTS, FRAP methods, caffeine content and phenolic compounds by HPLC. Principal component analysis was used to determine the effective treatments on bioactive properties. Coffee brews prepared with decoction method contained higher contents of total phenolic, total flavonoid, and total tannin as compared to the infusion method. On the other hand, antioxidant activity of coffee brews by DPPH and ABTS radical methods showed an opposite trend. Similar to antioxidant activity, infusion method was better to obtain higher amounts of catechin, caffeic acid and quercetin in coffee brews. The brewing method did not cause a significant difference in caffeine and rutin contents. Brewing time had major effects on several bioactive compounds, and their amounts showed an increase after extending the time of brewing.
... 27−29 Polyphenols such as chlorogenic acid and caffeic acid are present in high levels in coffee, and catechins are abundant in tea. 30,31 These are biologically active molecules that exert a variety of beneficial effects, including antioxidant and anticancer activities. 32,33 Intriguingly, polyphenols in coffee and tea also act as prooxidants, reducing O 2 to form the oxidant H 2 O 2 ( Figure S1), which is associated with the antimicrobial activity of these compounds. ...
Article
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Peroxygenases are promising catalysts for use in the oxidation of chemicals as they catalyze the direct oxidation of a variety of compounds under ambient conditions using hydrogen peroxide (H2O2) as an oxidant. Although the use of peroxygenases provides a simple method for oxidation of chemicals, the anthraquinone process currently used to produce H2O2 requires significant energy input and generates considerable waste, which negatively affects process sustainability and production costs. Thus, generating H2O2 for peroxygenases on site using an environmentally benign method would be advantageous. Here, we utilized spent coffee grounds (SCGs) and tea leaf residues (TLRs) for the production of H2O2. These waste biomass products reacted with molecular oxygen and effectively generated H2O2 in sodium phosphate buffer. The resulting H2O2 was utilized by the bacterial P450 peroxygenase, CYP152A1. Both SCG-derived and TLR-derived H2O2 promoted the CYP152A1-catalyzed oxidation of 4-methoxy-1-naphthol to Russig's blue as a model reaction. In addition, when CYP152A1 was incubated with styrene, the SCG and TLR solutions enabled the synthesis of styrene oxide and phenylacetaldehyde. This new approach using waste biomass provides a simple, cost-effective, and sustainable oxidation method that should be readily applicable to other peroxygenases for the synthesis of a variety of valuable chemicals.
... Since the early 20th century, coffee has developed into one of the world's most popular beverages and is now part of our daily routine and lifestyle (Yeretzian, 2017). The coffee beverage contains many bioactive compounds mainly polyphenols, such as phenolic acids, ferulic and pcoumaric and mostly chlorogenic in green beans and caffeine can be found after roasting (Król et al., 2020). According to Dong et al. (2017), besides the aroma and bitter taste, coffee also has attracted many by contributing to health benefits such as reducing colorectal cancer, cardiovascular disease and type 2 diabetes. ...
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Coffea liberica is one of the common coffee species grown in most Southeast Asia countries, especially in Malaysia. However, its production accounts for just 2% globally. In general, coffee beans’ roasting temperature and roasting time are critical factors determining the acceptance of roasted coffee by customers. However, there is still a gap in knowledge on the ideal roasting conditions of Liberica coffee based on the critical parameters. In this research, the central composite design (CCD) was used to assess the roasting time and the temperature in 13 treatments. The temperature ranged from 160 to 220°C and the time ranged from 15 to 30 mins. In the sensory analysis, 30 drinking panellists from local and international countries assessed the coffee brews' acceptability and the sensory attributes considered were colour, aroma, taste, and mouthfeel. By using response surface methodology (RSM), the optimum roasting conditions were determined based on the sensory analysis applied. The colour value of both roasted and ground coffee (p<0.05) was significantly influenced by roasting temperature and time, but only roasting temperature (p<0.05) affected the sensory acceptability of the coffee brew. The optimal roasting conditions were shown to be 197°C for 12.30 mins, corresponding to the roasting characterised by the following colour of the roasted Liberica beans: L* 30.43, a* 11.33 and b* 15.77 respectively. The disparity between Liberica coffee preference by tworegion panellists was also examined by a two-sample T-test, proving no difference between local and international selection.
... On the other hand, some studies claim that the level of caffeine increases as the degree of roasting increases, reaching a peak in light and medium-roasted coffee before beginning to decline in dark-roasted coffee. It is anticipated that increasing the temperature can reduce the water content of the coffee beans, thus helping to release volatile compounds (e.g., caffeine) from coffee; indeed, the caffeine levels were reduced significantly compared to the light and medium roast coffee after increasing the temperature to higher limits (dark roast) (79)(80)(81). ...
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Coffee, one of the most commercially important crops grown, is distributed and traded globally in a multi-million dollar world industry. This exciting new book brings together in one volume the most important recent developments affecting the crop. Contributions from around 20 internationally-respected coffee scientists and technologists from around the world provide a vast wealth of new information in the subject areas in which they are expert. The book commences with three cutting-edge chapters covering non-volatile and volatile compounds that determine the flavour of coffee. Chapters covering technology follow, including comprehensive information on developments in roasting techniques, decaffeination, the science and technology of instant coffee and home / catering beverage preparation. The physiological effects of coffee drinking are considered in a fascinating chapter on coffee and health. Agronomic aspects of coffee breeding and growing are covered specifically in chapters concentrating on these aspects, particularly focussing on newly-emerging molecular and cellular techniques. Finally, recent activities of some international organisations are reviewed in a lengthy appendix. The editors of Coffee: Recent Developments have drawn together a comprehensive and extremely important book that should be on the shelves of all those involved in coffee. The book is a vital tool for food scientists, food technologists and agricultural scientists and the commercially important information included in the book makes it a 'must have reference' to all food companies involved with coffee. All libraries in universities, and research stations where any aspect of the coffee crop is studied or taught should have copies of the book available.
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Epidemiological studies indicate that coffee consumption reduces the risk of Parkinson’s disease (PD) and Alzheimer’s disease (AD). To determine the factors involved, we examined the protective effects of coffee components. The test involved prevention of neurotoxicity to SH-SY5Y cells that was induced by LPS/IFNγ or IFNγ released from activated microglia and astrocytes. We found that quercetin, flavones, CGA and caffeine protected SH-SY5Y cells from these toxins. They also reduced the release of TNFα and IL-6 from the activated microglia and astrocytes, and attenuated the activation of proteins from P38 MAPK and NFκB. Following exposure to toxin containing glial stimulated conditioned medium, we also found that quercetin reduced oxidative/nitrative damage to DNA, as well as to the lipids and proteins of SH-SY5Y cells. There was a resultant increase in [GSH]i in SH-SY5Y cells. The data indicate that quercetin is the major neuroprotective component in coffee against PD and AD.