Effect of method of processing specialty coffee beans (natural, washed, honey, fermentation, maceration) on bioactive and volatile compounds

The aim of this study was to determine the effect of various methods of processing, such as natural, washed, honey, anaerobic fermentation, and carbonic maceration, on the antioxidant activity and bioactive and volatile compounds in green and roasted specialty coffees from various countries of origin (Nicaragua, Ethiopia, Peru, Burundi). Chlorogenic acids were different between green coffees (P = 0.04). Roasting increased the total polyphenol and total flavonoid (TF) contents. TF content in roasted Peruvian (PER) beans was significantly higher (4.20 μg quercetin (QE)/mg) for natural processing than carbonic maceration (CM; 2.22 μg QE/mg), and antioxidant capacity was significantly higher for CM (85.7 μg Trolox (TE)/mg) than natural processing (59.5 μg TE/mg). Burundian coffees had the highest antioxidant capacity, with the highest values for naturally processed beans (128.8 μg TE/mg) compared to beans processed by anaerobic fermentation (105.4 μg TE/mg). 2-Furanmethanol, a volatile compound, was a major compound in all roasted coffees, with a mean relative abundance of 21.52–32.53%. The type of processing affected the content of bioactive and volatile compounds in specialty coffees. However, anaerobic fermentation maintained a high level of bioactive compounds and contributed to the antioxidant activity of the roasted coffee, depending on the country of origin.