Antioxidant activity and estimation of melanoidin content in commercial roasted coffee

Abstract

Coffee contains several bioactive compounds, highlighting the antioxidants, whose consumption has been correlated with reduced incidence of chronic and degenerative diseases. Among 100 known species of the genus Coffea the most important economically in the international trade are Coffea arabica (arabica coffee) and Coffea canephora (robusta coffee), usually found as blends in commercial products. Arabica coffees present a higher sensory quality. The components associated with the antioxidant activity (AA) of coffee beverages included the class of phenolic compounds (especially 5-CQA) and caffeine, which have been most commonly studied, and melanoidins produced in the roasting process, for whom no data are available in the literature. Different methods are used to characterize the antioxidant capacity of foods, but there is no efficient and universal methodology of measurement. In this paper, roast and ground Brazilian coffees, commercialized under different designations (37 samples) were analyzed for the level of melanoidins, by spectrophotometry, and the antioxidant activity, by ABTS and total phenolics (Folin- Ciocalteau). All the products evaluated showed significant antioxidant activity. Differences observed in the estimation of the content of melanoidins indicated different roasting processes. Considering the different categories, the Gourmet coffees were characterized for lower values of AA, indicating that besides the degree of roasting, the coffee species used influenced the functionality of the product.