Effects of Sample Preparation Methods on the Isoflavones of Red Clover

Isoflavone levels in red clover samples, which were oven-dried at temperatures below 80 °C or frozen, did not differ from fresh clover samples. Quantitative estimation of isoflavones can be made on dry red clover samples provided they are first moistened to hydrolyze the isoflavone glycosides. Partial hydrolysis of glycosides resulted from drying at high temperatures or from freezing treatments.