UBC Theses and Dissertations
Nutritional studies on high lysine barley lines from the Alberta agriculture breeding program, 1977 harvest Imbeah, Maleena
Recent years have brought a greater awareness of the need for more plentiful as well as more nutritious foods. Discoveries of strains of maize, barley and other cereals having higher levels of essential amino acids have shown that nutritional quality of cereals can be improved through plant breeding. In the experiments reported here, the nutritional value of three cultivars from the Alberta Agriculture high lysine breeding program (Cultivars 1, 2 and 3), hiproly, and a normal commercial variety was studied. Amino acid analysis was done on each barley line to compare the ability of each to supply essential amino acids. The amino acid composition (g/16 g N) indicated virtually no differences except for cultivar 3 which had a much lower level of total essential amino acids than the rest. Barley proteins were separated by solubility tests to study the proportions in which albumins and globulins, glutelins and hordeins occur and to relate the levels of these protein fractions to the quality of the total protein. Hiproly and cultivars 1 and 2 were found to contain approximately the same levels of albumin plus globulin while cultivar 3 and Gait had lower proportions of these. The latter also had the highest proportion of hordein, an indication that its protein quality is low. Chemical determination of available lysine by dye binding difference gave inconclusive results. However, rat growth assays indicated Hiproly and cultivar 2 to be significantly superior in nutritional quality to Gait and cultivars 1 and 3. Nitrogen balance tests showed no significant differences between any of the five barleys. When the barleys were diluted to a standard protein content (12%), the supplementation with soybean meal or lysine plus other essential amino acids made significant improvements in rat performance, but lysine alone had no beneficial effect. This is an indication that the protein of these high lysine barleys is deficient in essential amino acids other than lysine. Apparent availability of lysine by faecal analysis gave results supporting the fact that high lysine barleys are superior in quality to the normal barley.
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