Aidilla Mubarak^1*, Kevin D. Croft², Catherine B. Bondonno³, Nurul Sakinah Din¹

¹School of Food Science and Technology, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia
²School of Biomedical Science, The University of Western Australia, M570, Level 4, Medical Research Foundation Building, Rear 50 Murray St, Perth, Western Australia 6847, Australia

³School of Medical and Health Sciences, Edith Cowan University, 270 Joondalup Drive, Joondalup, Western Australia 6027, Australia

Abstract

Information on the composition of chlorogenic acid, caffeine and antioxidant activity of Coffea liberica is scarce, albeit the importance of this species in some parts of the world. This study assessed the composition of chlorogenic acid, total phenolic, caffeine and free radical scavenging activity in green and roasted C. liberica in comparison to C. arabica. The compositions of these compounds were also investigated in C. liberica at different roasting degree. We found a comparable amount of chlorogenic acid in green C. liberica and C. arabica. However, roasted C. arabica had a significantly higher chlorogenic acid content than roasted C. liberica (p<0.05). Chlorogenic acid content significantly reduced in C. liberica after roasting when compared to green beans (p<0.05). There was an insignificant difference of caffeine content between the green and roasted beans of both coffee varieties. Total phenolic content were of comparable value between C. liberica and C. arabica for both green and roasted beans. There was a trend for higher total phenolic content in roasted C. liberica when compared to green beans, although significant difference was observed only in medium-dark roast (p<0.05). DPPH scavenging activity was comparable between C. arabica and C. liberica for both green and roasted beans, and was significantly reduced in C. liberica after roasting (p<0.05). Both green C. arabica and C. liberica had similar DPPH scavenging activity to the standards (BHT and α-tocopherol). These data can aid in promoting the production of C. liberica alongside C. arabica that has been regarded as a premium quality coffee.                       

Keywords: Antioxidant, Chlorogenic acid, Coffea arabica, Coffea liberica, Polyphenols