Coffee Fruit Roasting: An Approach To Enhance Yield and Bioactivities of Ethanol Extracts from Coffee Husk

This study aims to investigate theeffects of roastingdried coffeecherry on total phenol (TP), tannin, and flavonoid (TF) content andto examine the antioxidant and antimicrobial capacity of a coffeecherry husk-derived ethanol extract. Accordingly, the TP and TF contentafter different roasting regimens ranged from 9.00 to 123.49 mg GAE/gand 2.69 to 35.34 mg QE/g, respectively. The total tannin contentdecreased from 42.45 mg TAE/g to 0.27 mg TAE/g by the treatment. TheDPPH radical and hydrogen peroxide scavenging capacities extendedfrom 24.68 +/- 0.05 to 93.83% and 14.45 to 76.07%, respectively,while the ferric reducing capacity increased from 10.85 to 47.02 mgAAE/g. An extract with increased TP and TF as well as stronger antioxidativeactivity was found to be produced by mild temperature (150 degrees C)roasting for 25 min or 180 degrees C for 10 to 15 min, after which thepotency declines. The bacterial inhibition zones also increased from7.03 to 21.30 mm and from 6.00 to 15.77 mm forE. coli and S. aureus, respectively. Thisstudy demonstrated that roasting degrades tannin and enhances theantioxidant and antibacterial properties of ethanol extracts of coffeehusk.