Determination of Isoflavone (Genistein and Daidzein) Content, Total Oil Content and Fatty Acid Composition of Soybeans Grown in Different Environment and Treatments.

Michigan State University has been one of nine universities participating in a United Soybean Board project evaluating various soybean agronomic practices and their effect on yield.  Samples were collected from 16 different agronomic treatments with 4 replications and analyzed for various quality traits: isoflavone levels, total oil content, and fatty acid profile.  Isoflavones are a group of phytochemicals in some legumes that contribute to the healthful effects of soybeans in human and animal diets.  Daidzein and Genistein are isoflavone aglycones that are commonly found in soybeans. The major five fatty acids that are produced in soybeans are palmitic, stearic, oleic, linoleic and linolenic acid.

The objectives of this study were to determine the isoflavone (Genistein and Daidzien) content, total oil content and fatty acid composition of Michigan grown soybean using High Performance Liquid Chromatography, Accelerated Solution Extractor followed by Gas Chromatography. Data was analyzed using ANOVA and proc glm of SAS.

Agronomic treatments that are generally used to increase yields did not significantly change the isoflavone levels from the untreated check. Year and location had a significant effect on isoflavone levels. Use of a defoliant increased soy oil content significantly at 95% Confidence Interval (CI) in the year 2013. Foliar fungicide application increased oil content significantly at 95% CI. Nitrogen increased soy oil content significantly at 90% CI. Individual agronomic treatments had no significant effect on the fatty acid profile. When treatments were combined based on the inputs, there was a significant decrease in the amount of oleic acid, in the plots treated with a defoliant.