In addition, the linear configuration
of the all-trans lycopene might have difficulty fitting
into bile micelles compared to curved cis forms thus making
it difficult for the all-trans lycopene to be transported from the
food to the intestinal microvilli from which they can be absorbed
into the blood. Cis isomers of beta-carotene have also
been found to have greater efficiency of incorporation into micelles
than all-trans beta-carotene in vitro (Levin and Mokady,
1995; Ferruzzi et al., 2006), but were not found to be preferentially
absorbed by Caco-2 human intestinal cells (Ferruzzi
et al., 2006). Difference in carotenoid solubility and shape
may help explain their differences in bioavailability