Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)



First Advisor

Ivan S. Palmer


Selenium has been known to cause toxicity problems in animals since 1928. These problems arise when the element occurs in the soil at reasonably high concentration and is taken up by plants. Animals consuming the plants may then develop certain toxicity signs. More recently selenium has been shown to be an essential nutrient because of its involvement in the enzyme glutathione peroxidase (Rotruck et al., 1973). Evidence has been accumulating that the element may even help protect against cancer in humans (Shamberger, 1970). Consequently, there has been great interest in knowing about the content of selenium in various foods and also about the bioavailability of the seleium in these foods. In estimating the bioavailability of selenium from various sources, it would certainly be helpful to know the chemical form in which it exists in these sources. In fact, we know very little about the actual identity of selenium in foods. It is usually assumed that selenium substitutes for sulfur in the sulfur amino acids bu t direct proof for the occurrence of the selenoamino acids is often lacking - partially due to the small amounts of the selenium compounds present and due to their instability. In 1970, Olson et al. examined the forms of selenium in wheat and found approximately 50% present as selenomethionine but the other 50% was unknown. He was unable to show the presence of selenocysteine, but it was not known whether the compound was not present or if it decomposed during the isolation procedures. The objectives of this work are: 1. To examine the forms of selenium that occur in wheat, to see if the work of Olson could be repeated and to determine if selenocysteine was a significant portion of the unidentified selenium fraction. 2. To determine the presence and level of selenomethionine and selenocysteine in the high selenium yeast used to produce human selenium supplements.

Library of Congress Subject Headings

Yeast as feed -- Analysis
Wheat as feed -- Analysis



Number of Pages



South Dakota State University


No Copyright - United State