Effect of sulfur fertilization rates on wheat (Triticum aestivum L.) functionality

In a 6 x 3 x 3 factorial design, the effect of three sulfur fertilization rates (0, 8.4 and 16.8 kg/ha) on the properties of six spring wheat varieties grown in three locations in the US Midwest was evaluated. Dough properties were assessed via the Farinograph and GlutoPeak; contents of free amino acids and sugars in flour were determined by high-performance anion exchange chromatography. Bread volume and crust color were assessed as well. Overall, the main influence on flour, dough and bread properties was exerted by the growing location. However, sulfur fertilization rates significantly affected bread volume and the content of several free amino acids; the main ones being asparagine, glutamine, aspartate, glutamate, and alanine. At a fertilization rate of 0, 8.4 and 16.8 kg/ha, values ranged from 8.39 to 22.42, 7,92-22.563 and 6.67-25.05 mmol/kg, respectively, for asparagine, the precursor to the probable carcinogen acrylamide. GlutoPeak parameters appeared to be unaffected by sulfur fertilizer rate. Specific bread volumes ranged from 2.21 to 4.71 cm(3)/g. Across locations, the specific bread volume tended to be highest when samples had been grown at a sulfur fertilization rate of 8.4 kg/ha. Thus, the asparagine reductions achieved with the highest sulfur fertilization rate partially came at the expense of volume reduction.