POLYPHENOLS AND CAFFEINE OF GREEN AND ROASTED COFFEE BEANS, AS NATURAL ANTIOXIDANTS

Abstract

Green, light, medium and dark roasted coffee beans were used in the powder form to identify polyphenols by HPLC. Eleven components were identified in green, light and dark coffee roasted powder. Para Coumaric, Ferulic, Salicylic and Cinnamic acids were absent in medium roasted coffee powder. Polyphenol extract was more effective for the inhibition of lipid peroxidation than caffeine and mixture of polyphenols and caffeine. Antioxidant capacity by 2,2 ˉ-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid cation radical (ABTS +) showed a higher percentage of inhibition for polyphenols of green coffee (86.09 %) than light (82.67 %), medium (81.14 %) and dark (79.43 %). Caffeine of dark coffee samples has the lowest value of inhibition (72.0 %) followed by medium coffee sample (72.95 %) then light sample (75.05 %), finally the green coffee sample (77.34 %). It seems that oxidative activity was affected with two factors: temperature and period of roasting.