Trigonelline
Alkaloid present in green coffee (0.5-1.5% dry weight), precursor of niacin (vitamin B3) during roasting. Partly responsible for bitterness and caramel notes. Undegraded trigonelline contributes to the sweetness of lightly roasted coffee.
Background & Context
Trigonelline is a plant alkaloid found in coffee beans — present at approximately 0.6–1.3% of green coffee dry weight — that serves as both a flavour precursor and a bioactive compound with potential health significance. During roasting, trigonelline undergoes pyrolysis beginning at approximately 160°C, degrading into nicotinic acid (niacin/vitamin B3), pyridines, and pyrroles — contributing to coffee's characteristic roasted aroma. Lighter roasts retain more trigonelline (and thus more intact alkaloid); darker roasts convert a higher proportion to niacin and aromatic pyridines. Trigonelline is also notable for its distinct bitter taste and its pharmacological activity: research has linked trigonelline to hypoglycaemic effects (blood glucose reduction), neuroprotective properties, and inhibition of bacterial adhesion to tooth enamel — a finding that has generated interest in coffee's potential role in dental health. Research has shown that trigonelline degrades at roast temperatures above approximately 160 °C, releasing niacin (vitamin B3) as a by-product — one reason that coffee provides a modest but measurable contribution to daily niacin intake. The rate of degradation is also used as a proxy for roast progression in some industrial quality-control workflows. Trigonelline's interaction with chlorogenic acids during roasting further influences the overall bitterness profile, making it a compound of interest to both sensory scientists and pharmaceutical researchers studying coffee's physiological effects.
Practical Use
For specialty coffee professionals communicating with health-conscious consumers, trigonelline provides a scientifically grounded connection between coffee's complex chemistry and documented health effects. A medium-light roast contains more trigonelline than a dark roast — meaning the brewing method and roast level that specialty consumers prefer for flavour also delivers more of the intact alkaloid form. Espresso, despite its small volume, concentrates trigonelline more than filter coffee at equivalent dose — a double espresso may contain 60–90mg trigonelline vs. 40–60mg in a 200ml filter brew. Trigonelline's degradation products (pyridines, pyrroles) are also contributors to the "roasty" and "earthy" aromatic notes that characterise darker roast profiles — linking the chemistry directly to what coffee professionals describe in cupping vocabulary.
Related Terms
Related terms: Niacin (vitamin B3), Caffeine, Roasting, Maillard reaction, Coffee polyphenols.