Wheat preharvest herbicide application, whole‐grain flour properties, yeast activity and the degradation of glyphosate in bread

Summary The aim of this study was to determine the effects of wheat preharvest application of a glyphosate‐based herbicide (Roundup WeatherMax® with Transorb® 2 Technology) on whole‐grain flour composition and properties, including yeast activity. The effect of dough fermentation on the degradation of herbicide residues was also estimated. Grain samples from two hard red spring wheat varieties exceeded the maximum residue limits (5 mg kg−1) in Canada. Glyphosate had minor effects on wheat kernels composition and properties, including fructans content and yeast gassing power. No degradation of Roundup® or pure glyphosate was seen after dough fermentation for up to 4 h and baking. These results call for more scientific studies on glyphosate residues in wheat. If present in wheat flour, glyphosate residues are not degraded after bread‐baking.