| Abstract | This thesis gives an account of the investigation of the lipids of barley, oats and rye, their fractionation, composition end the gas chromatographic analysis of their fatty acid components. None of these oils has been thoroughly investigated previously, and only isolated data have been recorded, In the present work, therefore, the chemical and physical constants generally reported for comparable lipids of maize, rice, wheat and other plants have been determined (page 83).
An analysis by gas chromatography has been carried out for the first time and the fatty acid composition of glyceride and phosphatide fractions recorded (page i140). This eliminates the necessity for determining thiocyanogen, Reichert-Neissel and Polenske values which have been used by earlier workers for calculating fatty acid composition by empirical methods. The tedious separations into soluble and insoluble, or liquid and
solid acids and their subsequent analysis has also been avoided.
The phospholipids have been separated from the oil extracted from the grain and obtained as two fractions, one, ethanol~soluble, a lecithin of good purity; the other, ethanol-insoluble, comprising the so-called “cephalin" components. Analysis by gas chromatography has enabled interesting comparisons to be made for the first time between the fatty acid composition of the glyceride and phospholipid fractions from the source, which many of the earlier workers have not done. This is necessary since fatty acid composition varies considerably with climate, age of the grain, and strain or species of cereal, Several differences are observed, most notably the increased saturation of the acids of the “cephalin" fraction.
The "cephalin" fraction of all three cereals has been analysed qualitatively by paper chromatography, and shown, for the first time in the case of barley and oats, to contain combined serine as well as ethanolamine (page 91). In the case of rye, the work of Schulte and Krause (1951) has been confirmed, but as yet it is not certain whether the serine is present as phosphatidylserine. Carbohydrates, complexed with the extracted lipid and phospholipid, some of which have already been reported, have been identified by paper chromatography (page 85). from all three cereals, phosphatidic acids and phosphatidylinositol have been isolated by methanol extraction and identified for the first time, indicating that these compounds are more widely distributed than was originally thought. It seems certain that both exist as salts, and that the former occur mainly as hydrolysis products of the intact phosphatides. A serine containing phospholipid also occurs as an impurity with the phosphatidic acids (Chapter 13).
In conclusion, the results obtained from this work have mainly concerned the chemistry of the lipids and their occurrence and distribution. Interesting comparisons of fatty acid composition have been made and many of the individual fractions isolated have proved to be of considerable interest and provide topics for further research. |
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