The lipid components of white potato tubers (Solanum tuberosum).

Four Canadian varieties of potatoes were examined for their lipid composition. Lipids, extracted with chloroformmethanol, were shown by TLC and column chromatography to consist of 16.5% neutral lipids, 45.5% phospholipids and 38.1% glycolipids. Among the phospholipids and glycolipids, phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl inositol, the galactolipids and the sterol glucosides were the major lipids. The predominant fatty acids were palmitic (19.5%), linoleic (44.8%) and linolenic (30.4%, in Kennebec). Analyses of the fatty acids of stored potatoes showed a marked decrease in linoleic acid and an increase in linolenic acid, in the Irish Cobbler and Sebago potatoes. beta-sitosterol comprised 85.0% of total sterols. Nearly half of the carotenoids was lutein (xanthophyll), the others being alpha-carotene, beta-carotene, an unidentified pigment and lutein epoxide.