Changes in total and individual crocetin esters upon in vitro gastrointestinal digestion of saffron aqueous extracts.

Changes that may be expected in crocetin esters (crocins) upon digestion were examined in saffron aqueous extracts for the first time. Chemical characterization of total and individual crocins and other bioactive compounds was achieved by UV-vis spectrophotometry, RP-HPLC-DAD, adn LC-ESI-MS. Antioxidant activity was evaluated using in vitro assays and the comet assay. The observed loss for both total and trans-crocins was higher in saffron (similar to 50%) than in gardenia extracts (similar to 30%), which were also examined for comparison. Loss was lower than that reported for hydrophobic carotenoids. cis-Isomers were less affected, leading to the hypothesis that trans/cis isomerization may occur in parallel to degradation reactions. Monitoring changes in the extracts at oral, gastric, or intestinal phases, separately, verified this view pointing out the critical effect of pH, temperature, and duration of process but not of digestive enzymes. No isomerization and less degradation (<20% loss) was evidenced when pure trans-crocetin (di-beta-D-gentiobiosyl) ester was subjected to gastric or intestinal conditions.