Transformation of chlorogenic acids during the coffee beans roasting process

Due to the recently discovered biomedical activity of chlorogen acid, the interest in its physicochemical and pharmaceutical properties has increased. The plant product most frequently mentioned as remarkably rich in this compound is coffee beans. The present paper shows that the roasting process of coffee beans not only leads to the degradation of chlorogenic acid isomers to volatile components, the fact well known from the literature, but also causes their transformation to quinic acid and its epimer and to four chlorogenic acid lactones (basic and epimeric forms of 3- and 4-O-caffeoylquinic acid lactones) and changes the ratios between the amounts of chlorogen acid isomers and dicaffeoylquinic acids isomers. It is also shown that the increase of water content above its standard level in the initial green coffee beans slows down only the changes occurring during the roasting process.