Soybean seeds contain several secondary metabolites that have health beneficial properties. Isoflavones have generated considerable interest, but other compounds including tocopherols (toc) and lutein also have commercial value and potential. Tocopherols are natural lipophilic antioxidants with vitamin E biological activity, which are found widely in higher plants. They were reported to have potential in preventing several chronic diseases, including kidney and lung diseases (Hanson et al., 2016;Tasanarong et al., 2013).Tocopherols are classified into four different types: α-, β-, γ-and δ-toc, distinguished by the amount and position of methyl groups on the chromanol ring. While γ-toc represents the greatest proportion of toc in mature soybean seeds (Seguin et al., 2009), most interest for toc resides in α-toc as it can preferentially be absorbed and accumulated in humans, and thus has the greatest relative vitamin E activity (Rigotti, 2007). Globally, soybean is an important source of vitamin E.

Soybean [Glycine max (L.) Merr.] is an important source of health-beneficial compounds, including soysaponin I. A field study was conducted for 11 years in Ottawa, ON to assess the impacts of temperature and precipitation during specific growth stage intervals on soyasaponin I concentration in three soybean cultivars. Soyasaponin I concentration response to air temperature and precipitation variables were observed at specific growth stage intervals for some cultivars. The response was complex and cultivar specific. Overall, reproductive stages were more responsive and 20°C appeared to be a critical threshold in determining soybean soyasaponin I concentration response to air temperature.