Contents of chlorogenic acids and caffeine in various coffee-related products

Abstract

Coffee is the most popular beverage in the Republic of Korea, other than Korea's traditional green tea. Coffee 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 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 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. 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.

Keywords: Asian country; Caffeine; Caffeine/CGAs ratio; Chlorogenic acids; Coffee shop.

Graphical abstract

Fig. 1

Identification of 3-CQA, 4-CQA, 5-CQA, 3- FQA, 3,4-diCQA, 3,5-diCQA, 4,5-diCQA, and caffeine from chromatograms of the roasted and ground coffee samples.

Fig. 2

The mean amounts (mg/serving) of total CGAs and caffeine in the nine subgroups. (Error bars correspond to the standard deviation of measurements). RTD denotes ready-to-drink. The different letters are significantly different in mean values of total chlorogenic acid and caffeine in nine groups based on Tukey’s test (P < 0.05).

Fig. 3

The mean value of the caffeine/CGAs ratios of the nine sub-groups. (Error bars correspond to the standard deviation of the measurements.). RTD denotes ready-to-drink. There were no significant differences in the mean caffeine/CGA ratios between the nine groups based on Tukey’s test at a 5% probability (P > 0.05).