Synthesis and availability of niacin in roasted coffee.

The coffee bean contains about 1% of trigonelline that is demethylated at temperatures approaching 200 degrees C; it is partially converted into nicotinic acid. This operation is mainly proportional to the severity of dry heat treatment; various other physico-chemical factors also influence the synthesis of niacin during the roasting. The niacin content of weakly roasted commercial coffee is about 10 mg/100 g (American coffee) and it reaches 40 mg in heavy roasted coffees, i.e. Italian coffee. Caffeine-free coffee is lower in niacin than the corresponding raw coffee. The drinking retains 85% of the niacin formed during roasting; it is totally available for the organism and can constitute a noticeable part of the daily supply in niacin.