Impact of the Roast Level on Chemical Composition of Coffee from Colombia

Abstract

During the roasting process, a cascade of chemical reactions occur, from which non-volatile compounds degrade and form new compounds with potential aroma attributes. Considering that the roasting process significantly influences the biologically active compound concentration and some unwanted compound formation, such as acrylamide, it is crucial to understand the roasting process from both positive and negative aspects. The aim of this study was to evaluate the chemical composition changes in different roast level coffee samples from Colombia. The moisture, pH, acrylamide, total phenolic, and flavonoid content, and the volatile compound profile were analysed for coffee samples roasted at three different roast levels (light, medium, dark). The results showed a decrease of total phenolic and flavonoid concentration with increased roast level. Acrylamide concentration reached the highest peak in the medium roasted and the lowest in dark roasted coffee. With increasing roast level, the volatile organic acid concentration decreased, while furan and phenol compound concentration increased in the dark roasted coffee. Dark roasted coffee had the lowest acrylamide and organic acid concentration, and the highest pH in brew, which would be more suitable for coffee consumers with a sensitive stomach.