Forskning

April 12, 2012

Influence of coffee roasting on the incorporation of phenolic compounds into melanoidins and their relationship with antioxidant activity of the brew

D Perrone et al, Influence of coffee roasting on the incorporation of phenolic compounds into melanoidins and their relationship with antioxidant activity of the brew, Journal of Agricultural and Food Chemistry, 2012, article just accepted.

In the present study, the influence of coffee roasting on free and melanoidin-bound phenolic  compounds and their relationship with the brews’ antioxidant activity (AA), evaluated by TRAP  TEAC and TRAP, were investigated. Changes in the relative content of free chlorogenic acids  (CGA), free lactones, and melanoidin-bound phenolic acids during roasting indicate that phenolic  compounds were incorporated into melanoidins mainly at early stages of the process, being  thereafter partly oxidized to dihydrocaffeic acid, and degraded. Although less than 1% of CGA in  green coffee was incorporated into melanoidins during roasting, the relative content of melanoidin bound phenolic acids increased significantly during this process, reaching up to 29% of total  phenolic compounds in brews from dark roasted coffees. Regardless of the AA assay used and considering all roasting degrees, the overall contribution of CGA to the AA of the whole brews was  higher than that of melanoidin-bound phenolic compounds. It was estimated that the latter  compounds contributed to 25% – 47% of the AA, depending on the assay used.