Effects of boiling and frying on the bioaccessibility of beta -carotene in yellow-fleshed cassava roots (Manihot esculenta Crantz cv. BRS Jari).

摘要

Background. The effects of boiling and frying on the bioaccessibility of all-trans- beta -carotene in biofortified BRS Jari cassava roots have not been investigated, although these are conventional methods of cassava preparation. Objective. The aims of the present study were to investigate beta -carotene micellarization efficiency of yellow-fleshed BRS Jari cassava roots after boiling and frying, as an indicator of the bioaccessibility of this carotenoid, and to apply fluorescence microscopy to investigate beta -carotene in the emulsified fraction. Methods. Uncooked, boiled, and fried cassava roots were digested in vitro for the evaluation, by reversed-phase high-performance liquid chromatography (HPLC), of the efficiency of micellarization of all-trans- beta -carotene in BRS Jari cassava roots. Fluorescence microscopy of the micellar fraction was used to confirm the presence of beta -carotene in the emulsified fraction and to observe the structure of the microemulsion from the boiled and fried cassava samples. Results. Fried cassava roots showed the highest (p<.05) micellarization efficiency for total carotenoids and all-trans- beta -carotene (14.1+or-2.25% and 14.37+or-2.44%, respectively), compared with boiled and raw samples. Fluorescence microscopy showed that after in vitro digestion there were no carotenoid crystals in the micellar fraction, but rather that this fraction presented a biphasic system compatible with emulsified carotenoids, which was consistent with the expected high bioavailability of beta -carotene in this fraction. Conclusions. Increased emulsification and bioaccessibility of beta -carotene from fried biofortified BRS Jari cassava roots compensates for chemical losses during preparation, indicating that this preparation is suitable for home use of BRS Jari cassava roots and might represent a relatively good food source of bioavailable provitamin A.