Competition experiments were carried out between different cultivars of manioc (Manihot esculenta Crantz) in the terra firme ecosystem (Manaus, Amazonas, Brazil), with the productivity and pro-vitamin A carotene content. Roots from sevem cultivars of yellow manioc were selected for the identification and quantification of carotenes with vitamin A activity, according to the method described by Rodriguez. Pro-vitamin A loss due to processing and storage of the flour was also determined. The presence of three b - carotene isomers was noted (13 - cis - β - carotene, all trans β - carotene and 9 - cis - β - carotene). The amount of vitamin A present in the roots varied from 4.4 to 18.8 retinol equivalents. The loss of vitamin A due to processing was high, ranging from 25.3 to 40.0 %. The storage of the roots for six months in transparent plastic bags at room temperature and exposure to the sun, resulted in a total degradation of the carotenoids. The results allow one to conclude that three cultivars (IM 232; IM 104 and BGM 021) containt the highest pro-vitamin A content.
Carotene; manioc; flour; provitamin A