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Journal of Advanced Research
Original article
Contents of chlorogenic acids and caffeine in various coffee-related
Jong-Sup Jeona,, Han-Taek Kima, Il-Hyung Jeonga, Se-Ra Honga, Moon-Seog Oha, Mi-Hye Yoona,
Jae-Han Shimb, Ji Hoon Jeongc, A. M. Abd El-Atyd,e,
a Public Health Research Division, Gyeonggi Province Institute of Health and Environment, 95, Pajang cheon-ro, Jangan-gu, Suwon-Si, Gyeonggi-do 16205, Republic of Korea
b Natural Products Chemistry Laboratory, College of Agriculture and Life Sciences, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju 500-757, Republic of Korea
c Department of Pharmacology, College of Medicine, Chung-Ang University, 221, Heuksuk-dong, Dongjak-gu, Seoul 156-756, Republic of Korea
d Department of Pharmacology, Faculty of Veterinary Medicine, Cairo University, Giza 12211, Egypt
e Department of Medical Pharmacology, Medical Faculty, Ataturk University, 25240-Erzurum, Turkey
h i g h l i g h t s
g r a p h i c a l
a b s t r a c t
 The total amount of CGAs and caffeine
were quantified in different types of
coffee-related drinks.
 The coffee with the highest content of
CGAs was unblended roasted and
ground coffee sold in supermarkets.
 The most caffeine-rich coffee was
Americano coffee from coffee shops.
 The coffee with the highest value of
caffeine/CGAs ratio was milk-added
RTD coffee.
 According to caffeine/CGAs ratio, the
good quality coffee was found to be
the unblended ground coffee from
a r t i c l e
i n f o
a b s t r a c t
Article history:
Coffee is the most popular beverage in the Republic of Korea, other than Korea’s traditional green tea. Coffee
Received 31 October 2018
Revised 2 January 2019
Accepted 4 January 2019
Available online 9 January 2019
contains many physiologically active substances, such as chlorogenic acids (CGAs) and caffeine. Previous
studies have focused on the content of CGAs and caffeine in brewed coffee. This study quantified the total
amounts of CGAs and caffeine using high-performance liquid chromatography coupled with a diode array
detector in 83 various coffee-related products, such as instant coffee, roasted and ground coffee sold in
Chlorogenic acids
Caffeine/CGAs ratio
Coffee shop
supermarkets, ready-to-drink coffee, and Americano coffee sold in franchise restaurants in the Republic of
Korea. According to the results of this study, the coffee with the highest content of CGAs was unblended
roasted and ground coffee sold in supermarkets, with a mean value of 194.1 ± 67.7 mg/serving, and the most
caffeine-rich coffee was Americano coffee from coffee shops, with a mean value of 166.1 ± 37.5 mg/serving.
The caffeine/CGA ratios were determined in various coffee beverages because they are useful parameters for
Asian country
estimating the human health. The lowest mean caffeine/CGAs ratio of 0.5 ± 0.1 was found in unblended
ground coffee sold in supermarkets, and the highest mean ratio of 2.5 ± 1.4 was found in milk-added
ready-to-drink coffee. Adult caffeine tolerance is defined as 400 mg a day in the Republic of Korea.
Peer review under responsibility of Cairo University.
Corresponding authors.
2090-1232/ 2019 The Authors. Published by Elsevier B.V. on behalf of Cairo University.
This is an open access article under the CC BY-NC-ND license (
J.-S. Jeon et al./Journal of Advanced Research 17 (2019) 85–94
However, this value highlights the importance of medicines, carbohydrate beverages, tea, chocolate, cocoa
products, energy drinks and other sources of caffeine that can contribute to the total intake of caffeine.
 2019 The Authors. Published by Elsevier B.V. on behalf of Cairo University. This is an open access article
The purpose of this study was to evaluate the contents of CGAs
and caffeine in instant coffees (including instant mix coffee),
Coffee has been the most commercialized food item for decades.
ready-to-drink coffees, roasted and ground coffees from supermar-
Therefore, after water, coffee is the most widely consumed and
kets, and Americano coffees sold in coffee shops, fast food restau-
traded beverage in the world [1,2]. Epidemiological and experi-
rants, and bakery shops in the Republic of Korea. In addition, the
mental studies have shown positive effects of regular coffee drink-
caffeine/CGAs ratio, a good marker of the degree of roasting of cof-
ing on a variety of aspects of health, such as psychoactive response,
fee beans, was examined to compare the difference in the quality
neurological and metabolic disorders, and liver functions [3].
of coffee beans among various coffee beverages. The ratio is gener-
According to a recent prospective study on the association of coffee
ally associated with brewed coffee; however, other studies have
intake with total and cause-specific mortality in Japan, habitual
also reported the ratio in instant coffee [31]. The unit of mg/serving
coffee consumption is associated with a low risk of total mortality
in this study indicates the amount in hot water to be measured up
[4]. An interesting study showing that the frequent consumption of
that can be manufactured in the laboratory (confined to the sam-
instant mix coffee by Korean women was associated with a high
ples of the instant coffees, roasted and ground coffees from super-
prevalence of obesity was published in 2017 [5]. The culture of
markets in this study) and the very volume of the products as
drinking coffee is becoming popular in the Republic of Korea with
purchased, such as ready-to-drink coffees and Americano coffees
the Westernization of diet and changes in lifestyle. Korea’s per cap-
sold in coffee shops, fast food restaurants, and bakery shops.
ita coffee consumption is more than five times that of the Asia-
Pacific region [6].
Instant mix coffee that contains non-dairy or dairy creamer and
Material and methods
sugar was the most commonly consumed by Korean adults, with
an increasing trend among middle-aged and older individuals
and a declining trend among young men and women. Instant
mix coffee causes weight gain and insulin resistance, and the
potential benefits of coffee can be offset. Moreover, instant mix
coffee still accounts for a substantial amount of coffee consump-
tion, with approximately 10-fold higher consumption of instant
mix coffee than instant coffee in the Republic of Korea [5,7]. Addi-
tionally, the consumption of ready-to-drink coffee (including tradi-
tional canned coffees and coffees sold in new metal bottles,
polyethylene terephthalate (PET) bottles, and plastic cups) in Kor-
ean culture has increased rapidly in recent years [6]. Coffee con-
tains over 2000 different ingredients, such as carbohydrates,
fibres, nitrogen compounds, lipids, minerals, acids, and esters
[8,9]. Among these compounds, chlorogenic acids (CGAs) and caf-
feine are recognized as healthful components [1,10–18], and their
quantities in green coffee beans [19–22], ground coffees [13,23–
The analytical standard 5-CQA (CAS Number: 327-97-9) was
provided by Carl Roth GmBH (purity: >97%, Karlsruhe, Germany).
3-CQA (CAS Number: 906-33-2, purity > 95%), 4-CQA (CAS Num-
ber: 905-99-7, >95%), caffeine (CAS Number: 58-05-2, pur-
ity > 99%), glacial acetic acid, and potassium phosphate
monobasic were purchased from Sigma-Aldrich (St. Louis, MO,
USA). 3-FQA (CAS Number: 1899-29-2, purity 98%) was supplied
by Chem Faces (Hubei, China). 3,4-DiCQA (CAS Number: 14534-
61-3, purity > 95.0%), 3,5-diCQA (CAS Number: 2450-53-5, pur-
ity > 95%), and 4,5-diCQA (CAS Number: 32451-88-0, purity > 95%)
were obtained from Biopurity Phytochemicals (Sichuan, China).
HPLC-grade acetonitrile and methanol were provided by J.T. Baker
(Griesheim, Germany). A Barnstead Nanopure Diamond (Dubuque,
IA, USA) was used to make refined deionized water.
26], brewed coffees [27], and instant coffees [26,28] have been
reported in many articles. CGAs can be divided into three main
Samples and coffee sample preparation
groups: caffeoylquinic acids (CQAs: 3-CQA, 4-CQA, and 5-CQA),
dicaffeoylquinic acids (diCQAs: 3,4-diCQA, 3,5-diCQA, and 4,5-
A total of 83 different coffee-related products from 38 brands
diCQA), and feruloylquinic acids (FQAs: 3- FQA, 4- FQA, and 5-
and distinct production lots sold in Republic of Korea were col-
FQA) [29]. Previous studies have found that the quantity of each
lected and examined in this study. Nineteen instant coffee prod-
CGA and caffeine in commercial coffee beverages has various
ucts (5 brands), 28 Ready-to-drink coffee products (9 brands),
concentration ranges [26,27,30–34]. Our previous study using
and 18 roasted and ground coffee products (6 brands) were pur-
high-performance liquid chromatography (HPLC) showed that
chased from a supermarket. Additionally, 18 Americano coffees
the quantity of CGAs and caffeine in brewed coffee under various
from different franchise shops (coffee shops: 11 brands, fast food
conditions varies widely [35]. Although research results from other
restaurants: 4 brands, and bakery stores: 3 brands) were used
countries with an intrinsic coffee culture are not directly applicable
herein. The instant coffee used in this experimental work consisted
to the Republic of Korea, few studies have investigated the quanti-
of 13 types of 100% coffee, which included two decaffeinated cof-
ties of CGAs and caffeine and the caffeine/CGAs ratio in various
fees and 6 instant mix coffees. In the Republic of Korea, instant cof-
coffee-related beverages in the Republic of Korea. The more inten-
fee, including 100% powder coffee, is sold mainly in the form of
sive the roasting of the coffee bean is, the higher the caffeine/CGAs
sticks because of consumer convenience. Other studies have deter-
ratio will be because intensive roasting (time and temperature)
mined the CGAs and caffeine in instant coffees prepared from typ-
decreases the CGAs, whereas the amount of caffeine is not changed
ical weights (e.g., 2.0 g of instant coffee, equivalent to one
substantially by the roasting degree [26,31]. Given the associated
teaspoonful) of instant coffee dissolved in varied volumes of boil-
health problems, the most beneficial coffee in terms of the con-
ing water [26,31], which may lead to various concentrations of
tents of caffeine and CGAs is the coffee with the lowest caffeine/
CGAs and caffeine. Therefore, in this study, we purchased products
CGAs ratio, which corresponds to a high intake of CGAs and a
packaged in stick form, which better reflect the CGAs and caffeine
low intake of caffeine [31,33].
intake by an individual per serving for use in our experiments. The