Complementary to an efficacy trial carried out under the vitamin A for Africa Partnership, the retention of b-carotene in boiled,
mashed orange-fleshed sweet potato (OFSP), variety Resisto, was evaluated. The OFSP contained almost exclusively trans-bcarotene.
Studies were done to establish and evaluate the analytical procedure and to assess the natural variability of the b-carotene
content of OFSP. Because it was more efficient than other solvents, tetrahydrofuran:methanol (1:1) was chosen for extraction. The
high-performance liquid chromatographic method established showed good reproducibility. No loss of b-carotene was observed in
chopped/grated raw OFSP allowed to stand for 4 h, indicating that it was not prone to enzymatic oxidation. The b-carotene content
of medium-sized OFSP from the same harvest batch ranged from 132 to 194 mg/g. True retention (TR) was assessed using paired
samples and a formula that compensated for loss or gain of moisture and soluble solids. TR was 92% when medium-sized OFSP
covered with water was boiled for 20 min in a pot with the lid on; without the lid, boiling took 30 min and TR was 88%. When OFSP
of different sizes were boiled 30 min, covered with water in a pot with the lid on, TR was 70–80%. Although degradation occurred,
the b-carotene content of boiled/mashed OFSP was still substantial.
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