Hydroxycinnamic acids profiling, in vitro evaluation of total phenolic compounds, caffeine and antioxidant properties of coffee imported, roasted and consumed in Algeria

Abstract

BACKGROUD: Coffee is the most popular beverages consumed worldwide. It is an important source of antioxidants that can inhibit harmful effects of free radicals. OBJECTIVE: Comparative analysis of imported, roasted and consumed coffee in Algeria. METHODS: Investigation of the hydroxycinnamic acids profile of dark roasted coffee beans UHPLC-DAD-ESI-MSn analysis and in vitro evaluation of total phenolic compounds (TPC), caffeine and antioxidant activity using DPPH, ABTS, reducing power and phosphomolybdum methods in green and roasted Arabica and Robusta coffees beans and in coffee brews (Moka, Turk and Filter) prepared from a blend of Arabica and Robusta 20:80. RESULTS: Arabica and Robusta dark roasted beans had similar chromatographic profiles, being rich in caffeoylquinic acid and feruloylquinic acid isomers. Compared to green beans, roasted coffee beans had higher amounts of TPC while caffeine drastically decreased. The antioxidant activity increased after roasting, while the reducing activity was decreased. Filter coffee showed the highest levels of TPC and caffeine (0.69±0.05 g GAE/100 g, 0.96±0.08 mg/g respectively), which exhibits the higher reducing activity for the iron (III) and molybdate with 0.45±0.01 g GAE/100 g, 134.30±2.38 mg GAE/100 g, respectively. However, the Turk coffee exhibited the highest antiradical activity with 73.34% and 83.63% towards DPPH and ABTS, respectively. Significant correlations were recorded between TPC, caffeine and reducing power (r = 0.89) and (r = 0.97) respectively. CONCLUSION Despite the high roasting degree applied to green coffee beans, the consumed coffee constitute an important source of chlorogenic acids and its derivatives with high antioxidant potential that are beneficial for human health.