Submitted to: American Journal of Potato Research
Publication Type: Abstract Only
Publication Acceptance Date: 4/15/2007
Publication Date: N/A
Technical Abstract: Potato is a starchy tuber. This simple statement hides the fact that potato also is rich in phytonutrients. Variation in chemical composition and concentration is quite broad in the natural diversity available in the germplasm. Some of these phytonutrients are visually very dramatic. Anthocyanins range from red to purple. A solidly red or purple potato may have as much as 40 mg per 100 g Fresh Weight (FW). Anthocyanins occur as acylated glucosides of the aglycon anthocyanidin and are water soluble. A very different pigment class is comprised by the carotenoids. Solanum potato (Irish potato) has oxygenated carotenoids embracing the large category of xanthophylls. Thus, Ipomoea potato (sweet potato) has a well deserved name as a source of beta-carotene, a precursor of vitamin A, while Irish potato does not. The assortment in type of xanthophyll is numerous as well as encompassing a range of concentration. A white flesh potato may have 50 micrograms per 100 g FW of total carotenoids. Yellow and dark yellow fleshed potatoes may range from 150 to 400 micrograms. However, the papa amarilla cultivars (yellow potato) of South America may commonly have 1000 micrograms and extend up to 2600 micrograms in experimental breeding materials. Two xanthophylls found in potatoes, lutein and zeaxanthin, are major photo-protectant components of the human retina. Both anthocyanins and carotenoids are antioxidants. Antioxidant measurements vary greatly and roughly follow concentrations of anthocyanins and carotenoids, with strong suggestions of other significant unidentified antioxidants present. Cooking by various methods has an effect on concentration of both pigments and the antioxidant values but does not destroy them. Boiling of potato appears to increase the extractable total carotenoids and the accompanying antioxidant values. Breeding will result in phytonutrient enhancement of future varieties.