Volatile composition and antioxidant capacity of Arabica coffee

Abstract

This study compared the volatile and phenolic constituents of four Asian coffee varieties. The volatile components of Arabica coffee beans from Thailand (Doi Chang), Indonesia (Sidikalang and Sidikalang Kopi Luwak) and China (Yunnan) were extracted using dichloromethane and correlated with sensory data. The total concentrations of volatile compounds identified were 1239.04ppm (Yunnan), 1084.18ppm (Doi Chang), 1016.17ppm (Sidikalang) and 845.53 (Sidikalang Kopi Luwak). It was found that the Sidikalang Kopi Luwak coffee was most favourable with a well-balanced aromatic profile, though its overall profile was similar to that of Sidikalang. The Doi Chang and Yunnan coffees were perceived with distinctive sulphury notes mainly attributed to the sulphur-containing compounds of 8.32ppm and 12.63ppm, respectively. The phenolic compositions of the respective green and roasted coffee beans were also determined to assess their potential antioxidant activities. The total polyphenol content of the Sidikalang beans was the highest among the four coffee varieties. The antioxidant activities were measured using diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power assays (FRAP). Between the green and roasted coffee beans, the radical scavenging activity was similar, whereas the Arabica Sidikalang variety registered the highest ferric reducing capacity (p<0.05). Knowledge of the volatile composition and antioxidant capacities would facilitate a better understanding of Asian coffee quality.