Antioxidant capacity of coffees of several origins brewed following three different procedures

摘要

The antioxidant capacity of coffees (Arabica and Robusta) from 12 different points of origin (Uganda, Papua, Jamaica, Ethiopia, Kenya, Puerto Rico, "Caracolillo" Puerto Rico, Nicaragua, Colombia, Vietnam, Brazil and Guatemala) and two decaffeinated coffees from Colombia and Brazil prepared by three commonly used procedures (espresso, filter and Italian) were evaluated and compared with antioxidant standards and other phenolic compounds which have been described in coffee. All the coffees studied were very effective as scavengers of lipoperoxyl and OH~· radicals. The results also showed that there are no significant differences (p < 0.05) between the three ways of brewing (espresso, filter and Italian). The H_2O_2 scavenging capacity was analysed in freshly made coffee and 6 h later, the antioxidant activity slightly increasing with time. The filtered coffee showed a greater capacity to react with H_2O_2 (p < 0.05) than the Italian and espresso coffees. All the coffee samples improved the oxidative stability of butter (Rancimat test), espresso and Italian coffee providing greater protection (p < 0.05) than the filtered beverages. The coffee beverages from different origins did not show significant differences during 28 days of storage as regards the autoxidation of linoleic acid. However, filter brews produced stronger antioxidant activity (p < 0.05) during storage than espresso and Italian brewing techniques. The TEAC value provided a ranking in decreasing order of antioxidant capacity for samples at 6 min: Vietnam, Uganda, Nicaragua, Colombia, Brazil, "caracolillo", Puerto Rico, Guatemala, Kenya, Papua, decaffeinated Colombia, Ethiopia, Jamaica, and decaffeinated Brazil. In general, decaffeinated coffees (Colombia and Brazil) showed lower TEAC values than coffees with caffeine. Filter and Italian coffee analysed after 6 min exhibited higher TEAC value than espresso coffees. All the coffees studied are good antioxidants regardless of their cost, origin and way in which they are brewed (espresso, filter or Italian), which is a point worth considering.