Impact of Various Plasma Exposures Across Total Flavonoid Content in Robusta Coffee

The significance of flavonoids is well-established, particularly for their potential in treating diseases such as cancer and Alzheimer’s. This study focuses on comparing the flavonoid content in three coffee species: Arabica, Liberica, and Canephora (Robusta), and how plasma treatment might influence flavonoid levels in these species. Our hypothesis is that dielectric barrier discharge (DBD) plasma, with its reactive oxygen and nitrogen radicals, could enhance flavonoid content. In the first phase, filtered extracts were collected from each coffee species using hydroethanolic solvents and water-bath extraction to maximize the yield of bioactive compounds. The flavonoid content and antioxidant capacity was then characterized using Total Flavonoid Content and colorimetric assays. UV-Visible spectroscopy was employed to analyze differences in flavonoid content and antioxidant capacity across the species. The absorbance values for the Total Flavonoid Content assay were compared against a calibration curve of (+)- Catechin. Results indicated that Robusta coffee beans had significantly higher levels of total flavonoid content (mg Catechin/mL) compared to Arabica and Liberica beans. In the second phase, Robusta coffee beans were exposed to a DBD plasma jet generated by applying 5-10 kV (20-50 kHz) for 1, 5, 10, 15, and 20 minutes. Using the same protocol as the first phase to extract and analyze Total Flavonoid Content, it was revealed that 15 minutes of plasma exposure resulted in the highest flavonoid content.