|Brown, Charles - Chuck|
Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/19/2007
Publication Date: 12/1/2007
Citation: Brown, C.R., Culley, D., Bonierbale, M., Amoros, W. 2007. Anthocyanin, carotenoid contents, and antioxidant values in native south american potato cultivars. HortScience. 42(7):1733-1736. 2007. Interpretive Summary: The potato familiar to American consumers traces its orgin to South America. Before European contact potato was only located in South America. After Europeans arrived the potato was taken to Europe as a botanical curiosity. After less than a century it was grown as a food crop and has expanded ever since to every continent, becoming a main staple in countries such as Russia and Poland. In the center of origin, thousands of cultivars are still grown and many of them have anthocyanins and carotenoids imparting rich red, blue, yellow and orange colors. These pigments are antioxidants and thus contribute as phytonutrients to the nutritional value of these potatoes. The genetic resources available outside of South America for potato are different and generally less diverse than those in South America. This study found that South American cultivars may not be a genetic source of higher anthocycanin but are in some cases a source of carotenoid levels that are much higher than those available elsewhere. The South American cultivars with high carotenoid values are therefore a valuable source of this class of phytonutrient. Potato has xanthophyll types of carotenoids which are present in the human retina, and if available at high levels may be an important nutritional component in maintaining eye health. Therefore high carotenoid potatoes from South America are a valuable germplasm resource to introduce this character into future varieties in the US.
Technical Abstract: Tubers of native cultivars of potato from South America were analyzed to determine the total anthocyanin, total carotenoid and antioxidant values associated with them. Tubers were diced into pieces and frozen in liquid nitrogen prior to extraction. Total anthocyanins ranged from none to 23 mg/100 gram fresh weight (FW). Total carotenoids ranged from 81 to 2020 g/100 g FW. Oxygen radical absorbance capacity (ORAC) was measured for the anthocyanin (hydrophilic) and carotenoid (lipophilic) extracts. The hydrophilic ORACs ranged from 333 to 1407 mole Trolox equivalents/100 g FW. The lipophilic ORACs ranged from 4.7 to 30 nmole alpha-tocopherol equivalents/100 g FW. Analysis of variance using a general linear model revealed that if cultivars were divided into a high anthocyanin group (greater than 2 mg/100 g FW) and low anthocyanin group (less than 2 mg) hydrophilic ORACs were greater and total carotenoids were less in the high anthocyanin group. The cultivars consisted of 23 diploids, 7 triploids and 8 tetraploids. Total anthocyanins were greater the higher the ploidy. Total carotenoids were greater in diploids compared to triploids and tetraploids. Lipophilic ORAC in diploids was higher than in tetraploids. Although total anthocyanin or hydrophilic ORAC values reported here are not outside of the ranges found in North American and other breeding programs, total carotenoid and lipophilic ORAC values reach higher values suggesting that this trait combination is uniquely available in particular high-carotenoid native cultivars of South America.