Potential of golden potatoes to improve vitamin A and vitamin E status in developing countries

Potato (Solanum tuberosum L.) is the third most widely consumed plant food by humans. Its tubers are rich in starch and vitamin C, but have low or null levels of essential nutrients such as provitamin A and vitamin E. Transformation of potato with a bacterial mini-pathway for beta-carotene in a tuber-specific manner results in a "golden" potato (GP) tuber phenotype resulting from accumulation of provitamin A carotenoids (alpha- and beta-carotene) and xanthophylls. Here, we investigated the bioaccessibility of carotenoids and vitamin E as alpha-tocopherol (aTC) in boiled wild type and golden tubers using in vitro digestion. Golden tubers contained up to 91 mu g provitamin A carotenes (PAC)/g D, increased levels of xanthophylls, phytoene and phytofluene, as well as up to 78 pg vitamin E/g DW. Cubes from wild type and GP tubers were boiled and subjected to simulated digestion to estimate bioaccessibility of carotenoids and alpha TC. Retention in boiled GPs exceeded 80% for beta-carotene (beta C), alpha-carotene (alpha C), lutein, phytoene and alpha TC, but less than 50% for phytofluene. The efficiency of partitioning of total beta C, alpha C, E-lutein, phytoene, phytofluene and alpha TC in the mixed micelle fraction during small intestinal digestion was influenced by genotype, tuber content and hydrophobicity. Apical uptake of the compounds that partitioned in mixed micelles by monolayers of human intestinal Caco-2 cells during incubation for 4h was 14-20% for provitamin A and xanthophylls, 43-45% for phytoene, 23-27% for phytofluene, and 53% for alpha TC. These results suggest that a 150 g serving of boiled golden potatoes has the potential to contribute 42% and 23% of the daily requirement of retinol activity equivalents (RAE), as well as 34 and 17% of the daily vitamin E requirement for children and women of reproductive age, respectively.