antioxidants Article Comparison of the Antioxidant Activities and Volatile Compounds of Coffee Beans Obtained Using Digestive Bio-Processing (Elephant Dung Coffee) and Commonly Known Processing Methods Mesfin Haile 1 , Hyung Min Bae 1 and Won Hee Kang 1,2,* 1 Department of Horticulture, Kangwon National University, Chuncheon 24341, Korea; mesfi
[email protected] (M.H.);
[email protected] (H.M.B.) 2 Convergence Program of Coffee Science, Kangwon National University, Chuncheon 24341, Korea * Correspondence:
[email protected] Received: 17 April 2020; Accepted: 8 May 2020; Published: 11 May 2020 Abstract: There are different types of coffee processing methods. The wet (WP) and dry processing (DP) methods are widely practiced in different parts of coffee-growing countries. There is also a digestive bioprocessing method in which the most expensive coffee is produced. The elephant dung coffee is produced using the digestive bioprocessing method. In the present experiment, the antioxidant activity and volatile compounds of coffee that have been processed using different methods were compared. The antioxidant activity, total phenolic content (TPC), total flavonoid content (TFC), and total tannin content (TTC) of green coffee beans from all treatments were higher as compared to roasted coffee beans. Regarding the green coffee beans, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of elephant dung coffee beans was higher as compared to that of the DP and WP coffee beans. The green coffee beans had higher DPPH activity and ferric reducing antioxidant power (FRAP) value compared to the roasted coffee beans. The green beans of elephant dung coffee had a high TPC than the beans obtained by WP and DP methods.