Changes in the total phenolic contents, chlorogenic acid, and caffeine of coffeecups regarding different brewing methods

Coffee is among the most popular beverages consumed worldwide due to its taste, flavor, and alertness effects on drinkers. Besides, caffeine and chlorogenic acid are known as featured compounds of coffee, and there are various phenolic compounds, that demonstrate many benefits for human health. However, the concentrations of those compounds ingested into the human body are greatly dependent on how coffee infusions are prepared. The extraction efficiency of phenolic compounds, caffeine, and chlorogenic acid in the Arabica and Robusta coffee obtained from the light, medium, and dark roasting levels, using the hot brew (at 50°C and 90°C) and cold brew methods was studied. The total phenolic contents (TPCs) were measured by the Folin-Ciocalteu assay, while the first -order derivative spectrophotometry was used to determine the caffeine and chlorogenic acid. Generally, light-roasted Robusta had the highest caffeine (2.10±0.017% w/w), chlorogenic acid (5.63±0.011% w/w), and TPCs (45.5±0.9 mg GAE/g). For brewing experiments, 10 g of coffee was brewed (100 mL of water) for different extraction times. The results show that hot brewing at 90°C was the most efficient method for extracting the TPCs and chlorogenic acid, while cold brewing was better for extracting caffeine. Extraction efficiency increased with longer extraction times, especially for the light roasting level.