The crystalline form of carotenes and the food matrix in carrot root decrease the relative bioavailability of beta- and alpha-carotene in the ferret model.

OBJECTIVE: The objective of this study was to investigate the relative bioavailability (BV) of beta-carotene (BC) and alpha-carotene (AC) from different extracts of carrots utilizing the ferret model.
METHODS: Five groups of animals (n = 6) were provided free access to a carotenoid-free, vitamin A-adequate diet and tap water for 2 weeks, then for 3 consecutive days 10 mg of BC was provided in 30--40 mL of one of the following fluids as partial replacement for tap water along with diet: 1) commercial BC beadlets dispersed in distilled water (control), 2) non-heated carrot juice, 3) heated carrot juice, 4) non-heated isolated carrot chromoplasts, or 5) heated carrot chromoplasts. The animals were killed and samples of blood and tissues (liver, adrenal, lung, kidney, spleen) were collected and analyzed for AC and BC concentrations.
RESULTS: The tissue analysis of BC concentrations indicated that BC-beadlet-supplemented animals had significantly higher BC concentrations than other groups (p<0.01). Carrot chromoplast-supplemented animals had significantly higher tissue BC and AC concentrations than carrot juice-supplemented animals. Heat treatment tended to reduce the relative BV of carotenoids but the differences between heated and non-heated juices or isolated carrot chromoplasts were not significantly different.
CONCLUSIONS: These results suggest that the food matrix, probably pectin-like fibers, and the crystalline form of carotenoids in carrot chromoplast are the primary factors that reduce the relative BV of carotenoids from carrot juice.