Bioaccessibility and bioavailability

Carotenoid bioavailability refers to the fraction of the ingested carotenoid that is absorbed and becomes available for utilization in normal physiological functions or for storage in the human body. This chapter highlights food-related factors, which have been investigated intensely in recent years through in vitro bioaccessibility studies, the findings of which are generally coherent with those of human studies on bioavailability. For each of the factors cited here, in vitro bioaccessibility is discussed first, followed by bioavailability results from human studies. Although processing, especially thermal processing, can substantially decrease the carotenoid content, an increasing number of in vitro and human studies have shown that it can increase the carotenoid bioaccessibility/bioavailability. The magnitude of such increase depends on the cooking/processing conditions. Using an extrinsic stable isotope reference method, absorption of ß-carotene and a-carotene was found to be approximately twofold greater in commercial carrot puree than in boiled mashed carrot.