Soil Sulfur and Nitrogen Affect Wheat Flour Mixing Characteristics and Protein Features in Flour and Dough

ABSTRACT Background and Objectives Sulfur and nitrogen affect wheat yield and the protein content and quality. Hard red spring wheat (Albany cultivar) grown under six different soil nitrate application levels (0, 60, 120, 180, 240, and 300 lbs/acre) and two sulfur levels (0 or 20 lbs/acre) was used. Mixing characteristics of flours were determined using the Brabender Farinograph AT, while flour and dough were studied for their thiols and SDS cold protein solubility with or without dithiothreitol. Findings Nitrate‐only at 180 lbs/acre and nitrate and sulfur at 60:20 lbs/acre (3:1) flours had desirable mixing performance. Nitrate‐only fertilization did not affect cold protein extractability in dough and compacted flour proteins so that thiols could not be exposed even in the presence of chaotrope. Nitrate and sulfur application affected protein compactness but for 120:20 lbs/acre (A63) and 180:20 lbs/acre (A64) applications, while exposable thiols further decreased, decreasing as nitrate levels increased. Exposable thiols decreased in nitrate‐only doughs, with the no‐nitrate (A55), 120 lbs/acre (A57), and 180 lbs/acre (A58) showing greater decrease. Conclusions Sulfur singularly increased exposable thiols in dough and was not affected by presence of nitrate. Indeed, nitrate only or nitrate and sulfur together application seems to produce wheat flour that has a more ordered protein structure and improved association with solvent (water) when mixed into dough. Significance and Novelty: This has significance in fertilizer application in fields for wheat cultivation for specific end‐use.