The black scale on the scatter plot provides the location of each sample point where levels of a given component tend to cluster with a particular characteristic. Fig. 3 shows that clustered sample points together have the same roasting degree. Green coffee samples had a high content of 5-CQA, dicaffeoylquinic acids and more intracellular antioxidant activity. Light-roasted coffee samples had a relatively high 3-CQA and 4CQA content accompanied by powerful peroxyl radical observed in ORAC assay. Medium- and dark-roasted coffee samples with melanoidin content clustered with TEMPO radical scavenging capacity. In summary, we analyzed physicochemical changes in green and roasted coffee beans that ultimately affect antioxidant
Pearson correlation coefficients between physiochemical parameters and antioxidant activities in coffee brews.