In coffee beans, especially roasted, a significant part of hydroxycinnamic acid (HCAs) and their esters chloro-
genic acids (CHAs) is attached to melanoidins through both covalent and non-covalent bonds. Bound and, to a
greater extent, unbound HCAs, including those released from the polymerized material during digestion, can be
pivotal in preventing of many chronic civilization diseases. The aim of the study was to determine the amount of
free CHAs and those released from coffee extracts during in vitro digestion in various sections of the gastroin-
testinal tract, in the presence and absence of probiotic bacteria. The concentration of free CHAs was the lowest in
the stomach and achieved the highest levels in the large intestine. Probiotic bacteria caused significant release of
CHAs, and in the colon their concentration was the highest. The studies with Caco-2 and HT-29 cell lines showed
that digested coffee extracts had cytoprotective potential against tert-BOOH induced oxidative stress.