CHAPTER 31: β-Carbolines

Coffee is the major dietary source of harman and norharman, two β-carbolines with biological activities that might be implicated in coffee health effects. These β-carbolines are formed from tryptophan/tryptamines, with tetrahydro-β-carbolines as intermediates. Fermented plant foods are particularly rich in tetrahydro-β-carbolines, while thermally processed foods are richer in β-carbolines, with coffee attaining the highest amounts. No report of tetrahydro-β-carbolines in roasted coffee are found, but the norharman and harman amounts are highly variable, depending on the coffee species (C. arabica L and C. canephora Pierre), roast degree, and beverage type. Several techniques have been employed to analyze β-carbolines and tetrahydro-β-carbolines, in coffee and other food matrices. This chapter addresses the current knowledge on β-carboline analysis and content in coffee, compared to other food sources, and explores technological factors that might influence their amounts in coffee and other foods.