Retention of β-carotene in boiled, mashed orange-fleshed sweet potato

• Published in: Journal of food composition and analysis Vol. 19; no. 4; pp. 321 - 329
• Main Authors: van Jaarsveld, P.J., Marais, De Wet, Harmse, E., Nestel, P., Rodriguez-Amaya, D.B.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-06-2006
• Subjects: beta-carotene; boiling; cooked foods; cooking quality; crushing; enzymatic hydrolysis; food nutrient losses; Orange-fleshed sweet potato; Retention; reversed-phase high performance liquid chromatography; sweet potatoes; varieties; Vitamin A value; water content; β-carotene; Vitamin A value; β-carotene; Retention; Orange-fleshed sweet potato
• ISSN: 0889-1575; 1096-0481
• DOI: 10.1016/j.jfca.2004.10.007

Complementary to an efficacy trial carried out under the vitamin A for Africa Partnership, the retention of
β-carotene in boiled, mashed orange-fleshed sweet potato (OFSP), variety Resisto, was evaluated. The OFSP contained almost exclusively
trans-β-carotene. Studies were done to establish and evaluate the analytical procedure and to assess the natural variability of the
β-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
β-carotene was observed in chopped/grated raw OFSP allowed to stand for 4
h, indicating that it was not prone to enzymatic oxidation. The
β-carotene content of medium-sized OFSP from the same harvest batch ranged from 132 to 194
μg/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
β-carotene content of boiled/mashed OFSP was still substantial.