The compositions of the polar lipids in the free sad bound lipids from four varieties of experimentally cultivated potatoes were identified and quantified by thin layer- and gas-liquid chromatographies. The results were summarized as follows:
1. The glycolipids contained in the free and bound lipids were fractionated and identified as esterified sterol glycoside, monogalactosyl diglyceride, sterol glycoside, digalactosyl diglyceride, aad trigalactosyl diglyceride, of which the highest content to the total lipid quantity were 5.8% of esterified sterol glycoside in the free lipid and 6.1% of trigalactosyl diglyceride in the bound lipid. The content of monogalactosyl diglyceride in the free and bound lipids was almost the same, whereas the content of esterified sterol glycoside was higher in the free lipid than in the bound lipid, and the contents of sterol glycoside, digalactosyl diglyceride, and trigalactosyl diglyceride were higher in the bound lipid than in the free lipid on the contrary.
2. The phospholipid contained in the free and bound lipids were fractionated and identified as phosphatidyl ethanolamine, phosphatidyl glyceride, phosphatidyl choline, and phosphatidyl inositol, but the phosphatidyl glyceride was not detected in the free lipid. The highest content in the total lipid quantity was 3.3 % of phosophatidyl choline in the case of the free lipid, while 14.9 % of the phosphatidyl ethanolamine contained in the bound lipid was the highest. All other constituents of phospholipid were contained in larger quantity in the bound lipid than in the free lipid.
3. The fatty acid composition of glycolipid in the free and bound lipids was also the same as that of the total free and bound lipids. The differences were that the content of palmitic acid was higher in the glycolipid of the free lipid than in the total free lipid and the content of linoleic acid was lower in the glycolipid.
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