Date of Award
Master of Science
Conventional soybean [Glycine max (L.) Merr.] cultivars produce oil with [difference]110 g kg−1 palmitate and [difference]70 g kg−1 linolenate. Soybean oil with reduced palmitate content is desirable for cardiovascular health. Reduced linolenate content results in a more oxidatively stable oil that may not require partial hydrogenation. Partial hydrogenation produces trans-fatty acids, which are undesirable for human health. Tocopherol (vitamin E) is an antioxidant found in soybean oil. The objective of this study was to compare lines with reduced palmitate or reduced linolenate with normal lines for tocopherol content. Two experiments were conducted to make this comparison. In the first experiment, a total of 41 soybean cultivars and lines with palmitate contents ranging from 37 to 124 g kg−1 and linolenate contents ranging from 12 to 83 g kg−1 were compared for tocopherol content. Lines with reduced palmitate had a significantly higher mean total tocopherol content than lines with normal fatty ester content or with 10 g kg−1 (1%) or 25 g kg−1 (2.5%) linolenate. No significant difference in total tocopherol was observed between normal and 10 g kg−1 linolenate lines. In the second experiment, lines with 1% linolenate and lines with 7% linolenate were compared for tocopherol content. Three populations were formed by crossing three high-yielding conventional lines with three 1%-linolenate lines. For each population, 20 1%- and 20 7%-linolenate F3[subscript :]4 lines were evaluated in Isabela, Puerto Rico, in 2002. The same lines were evaluated at two locations near Ames, IA, in 2002. The mean total tocopherol content of the 1%-linolenate lines was 73 mg kg−1 lower in Population 1, 74 mg kg−1 lower in Population 2, and 91 mg kg−1 lower in Population 3 than that of the 7%-linolenate lines. At all individual locations, the mean total tocopherol of the 7%-linolenate lines was significantly greater than that of the 1%-linolenate lines in the three populations. The overlap in ranges of total tocopherol between the 1% and 7%-linolenate lines indicated that it should be possible to develop 1%-linolenate cultivars with acceptable contents of individual and total tocopherols compared with normal cultivars.
Kristen Lee McCord
McCord, Kristen Lee, "Association of modified fatty ester profiles with tocopherol content in soybean seed oil" (2003). Retrospective Theses and Dissertations. 19499.