Profile and levels of bioactive amines in instant coffee

The levels of ten free bioactive amines, as well as pH and color characteristics, were determined in different types and brands of instant coffee. The amines were extracted with trichloroacetic acid and quantified by ion-pair HPLC, post-column derivatization with o-phthalaldehyde and fluorimetric detection. Overall, nine amines were detected: serotonin, cadaverine, tyramine, spermidine, putrescine, histamine, agmatine, phenyletylamine and spermine. Tryptamine was not detected in any sample. Tyramine was present in every sample, followed by cadaverine and serotonin. Total amine levels in the dry instant coffee varied from 0.28 to 2.76 mg/100 g. Overall, serotonin was present at higher levels followed by cadaverine, tyramine and spermidine. Significantly higher tyramine levels were found in decaffeinated coffee and higher cadaverine levels were detected in decaffeinated and organic coffee. The levels of amines varied among lots of the same brand and among brands. The color characteristics varied among types of instant coffee. The pH of the beverage varied from 4.86 to 5.15, with higher levels in decaffeinated coffee. There was significant positive correlation between pH and the levels of tyramine and agmatine. Investigations are needed to ascertain the impact of these amines on coffee flavor and on human health, and to determine the factors which affect amine formation and accumulation in instant coffee.