Trigonelline content in coffee beans and the thermal conversion of trigonelline into nicotinic acid during the roasting of coffee beans.

The trigonelline content in coffee was determined by the microbiological assay method after demethylating the compound. The content was proved to be extremely high (up to 1% on the wet basis). When trigonelline was heated to above 180°C, it was converted into nicotinic acid. Although the conversion rate was low, a nutritionally significant amount of nicotinic acid was formed during roasting coffee beans because of the high content of trigonelline in coffee beans. The optimum heating condition for nicotinic acid formation was found at 220°C for 20min.