Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 29, 2001
Publication Date: N/A
Interpretive Summary: The yellow color in yellow-fleshed potato tubers is caused by carotenoids. This research identified and quantified the different carotenoids found in intensely colored yellow-fleshed diploid potatoes and compared this to two popular tetraploid potato cultivars. We found that lutein and zeaxanthin were two important carotenoids present in diploid potatoes at 3-13 times the amount found in the yellow-fleshed, tetraploid cultivar 'Yukon Gold' and at 4-23 times the amount found in the white-fleshed, tetraploid cultivar 'Superior'. These two carotenoids may help to protect against a variety of chronic diseases including cardiovascular disease, certain cancers, and age-related macular degeneration, the leading cause of blindness in the elderly. Also, we found that the yellow color, as measured by a colorimeter, was very closely related to the amount of carotenoids in the potatoes. This will provide scientists and nutritionists with a quick, easy, and inexpensive way to measure carotenoid content in breeding populations. This information is important to the potato industry and to consumers interested in improving their nutritional intake.
Technical Abstract: The yellow pigment in potato tuber flesh is caused by carotenoids that may protect against cancer, cardiovascular disease and macular eye degeneration. The purposes of this research were to: 1) identify and quantify the carotenoids present in eleven diploid clones and two tetraploid potato cultivars, and 2) determine the relationship between tuber yellow intensity and carotenoid content. Yellow intensity was measured by a colorimeter. Carotenoid analyses were performed on an automated HPLC system. Six major carotenoids were detected: neoxanthin, violaxanthin, lutein-5, 6-epoxide, lutein, zeaxanthin, and an unknown carotenoid. The total carotenoid content in the yellow-fleshed diploid clones was 3 to 13 times higher than the yellow-fleshed 'Yukon Gold' and 4 to 23 times higher than the white-fleshed 'Superior'. Both total and individual carotenoid contents were positively correlated with tuber yellow intensity. There was an exponential relationship between total carotenoid content and tuber yellow intensity. This suggests that selecting for more intense yellow flesh will result in higher levels of carotentoids. These specific diploid clones can significantly improve the nutritional status of commercial potatoes.