Quantification of Caffeine and Chlorogenic Acid in Green and Roasted Coffee Samples Using HPLC-DAD and Evaluation of the Effect of Degree of Roasting on Their Levels

Abstract

Chlorogenic acid and caffeine are among the important components in coffee beans, determining the taste and aroma. In addition, phenols and antioxidants content possess vital health values. The main aim of this study is to determine the levels of caffeine and chlorogenic acid in several coffee samples of different origins and degrees of roasting. The coffee samples were extracted using hot water. The levels of caffeine and chlorogenic acid were quantified using high-performance liquid chromatography (HPLC) equipped with a diode array detector, a reverse phase system, and an ODS column (C18). Total phenol and antioxidant contents were previously determined for the same samples. The results showed that the highest content of caffeine was found in the medium roasted coffee (203.63 mg/L), and the highest content of chlorogenic acid content was found in the green coffee (543.23 mg/L). The results demonstrated a negative correlation between the chlorogenic acid levels with the degree of roasting, while it showed a positive correlation between the caffeine levels with the degree of roasting till a certain point where the levels dropped in the dark roasted coffee. The origin of coffee samples did not show any effect on any of the measured variables. Antioxidant effects of coffee samples were largely determined by chlorogenic acid content.

Potential Antimicrobial Properties of Coffee Beans and Coffee By-Products Against Drug-Resistant Vibrio cholerae

“…Hence, we have demonstrated that roasting circumstances have a considerable impact on the features of the physicochemistry of CGA, but do not significantly affect caffeine thermally, which is consistent with the findings of most of the aforementioned studies ( 48 , 74 , 75 ), while this is the first report of a 2.5-fold decrease in CA in medium and dark coffee. Several studies have previously reported that CGA levels are lost during the roasting process of coffee beans.…”

Quantification of Total Phenols and Antioxidants in Coffee Samples of Different Origins and Evaluation of the Effect of Degree of Roasting on Their Levels

“…Results from a study—that was recently published by our research group—which determined the chlorogenic acids (CGAs) and caffeine content for the same coffee samples, have shown that the highest content of caffeine was found in the medium roasted coffee (203.63 mg/L), and the highest content of CGA was found in the green coffee (543.23 mg/L). The results demonstrated a negative correlation between the CGA levels with the degree of roasting, while it showed a positive correlation between the caffeine levels with the degree of roasting before it starts to decline in the dark roasted coffee [ 16 ].…”

“…Comparing these results with the current study, it can be concluded that the coffee samples with the highest CGA content have also shown the highest antioxidant activity, which suggests that CGAs alone rather than total phenolic content contribute to the antioxidant activity of coffee. Furthermore, the geographical origin did not seem to affect the content of either CGA or caffeine, as it did not affect the total phenolic content and antioxidant activity determined in this study [ 16 ].…”

“…All samples were prepared by water extraction similar to the way normally used when preparing the beverage, to investigate the individual’s intake of antioxidant phenols by consuming coffee brew. The secondary aim was to find a correlation (if any) between the antioxidant activity and total phenolic content of different types of coffee beans, with their caffeine, chlorogenic acids, and heavy metal content, the latter that were previously determined by our research group (Albals et al) (Awwad et al) [ 7 , 16 ].…”

The Biological Activity Mechanism of Chlorogenic Acid and Its Applications in Food Industry: A Review

“…CGA is a phenolic compound produced by plants, and the content in green coffee is very significant, of which 5-CQA is the most abundant, accounting for 50% of the total CGA in green coffee beans (based on dry weight) ( 12 ). Unroasted coffee beans are as high as 543.23 (mg/L), but with the increase of roasting degree, the content gradually decreases ( 62 ). In addition to coffee, fruits and vegetables as well as Chinese herbal medicines are also a wide range of sources of CGA.…”