CHAPTER 26. Isoflavones, Lignans and Other Minor Polyphenols

Among the minor phenolic compounds in coffee two are structurally similar to endogenous estrogens with weak estrogenic properties that are still little known: isoflavones and lignans. These compounds have been the subject of a limited number of studies and their first detection in low amounts in coffee dates back to 1998. In spite of being just minor coffee components, because of their interesting biological activities associated with the high coffee consumption worldwide, both isoflavones and lignans cannot be neglected. The present chapter aims at reviewing analytical methods and compositional data reported so far on these little considered coffee polyphenols. The overview evidences a remarkable variability in both the incidence and content of these minor coffee components. This variability may reflect the several adopted analytical methods which often have not been optimized for coffee matrices. The presence of other minor polyphenols in coffee fruits and to a lower extent in seeds will also be discussed.