Norharman and harman in instant coffee and coffee substitutes

Norharman and harman are two neuroactive beta-carbolines present in several plants and thermally processed foods, including roasted coffee. The objective of this study was to evaluate their amounts in commercial instant coffee-based and coffee substitute beverages (n = 48), with variable amounts of coffee, chicory, barley, malt, and rye. All samples contained variable amounts of both beta-carbolines, always with a higher Proportion of norharman than harman. The highest levels (p < 0.01) were found in 100% instant coffees, with mean amounts of 3.8 mu g/g and 1.5 mu g/g for NH and H. respectively, followed by plain chicory. The lowest amounts were found in 100% barley, with 1.1 mu g/g for NH and 0.3 mu g/g for H. The NH and H content was statistically higher (p < 0.01) in all mixtures with coffee when compared to those without it. Nevertheless, and except for 100% barley, the amounts provided by beverages based on coffee substitutes are within those reported for standard coffee brews. (C 2009 Elsevier Ltd. All rights reserved.