Isoflavone Levels in Soybeans

Canadian researchers determined isoflavone levels in early maturity soybean cultivars in different environments and their relationship to other seed characteristics. Twenty varieties were grown in replicated trials at two sites in Montreal, Canada during 2002 and 2003. Total isoflavone levels were significantly affected by cultivar, site and year. Total isoflavone levels ranged from 360 to 2,241 mug/g and averaged 851 mug/g across environments and cultivars. Variation across environments ranged from 20 to 100 percent for specific cultivars. Total isoflavone levels were on the average 40 percent higher in 2003 compared to 2002; a year with higher temperatures and a severe drought. Despite significant cultivar x year x site interactions, it was possible to identify soybean varieties with consistently high or low levels of total isoflavones. Weak positive correlations were seen between total isoflavone levels and seed yield, 100-seed weight and crude fiber levels of the seed. These results indicate that isoflavone levels of soybeans are influenced by genetics and environment.

Seguin, P. and co-workers. 2004. Isoflavone content of soybean cultivars grown in eastern Canada. J. Science of Food and Agric. 84(11): 1327-1332.