Impact of different nitrogen fertilizers and an additional sulfur supply on grain yield, quality, and the potential of acrylamide formation in winter wheat

Abstract

AbstractThe amino acid asparagine (Asn) plays a key role in acrylamide (AA) formation in strongly heated cereal foodstuffs. The influence of different nitrogen (N) fertilizers (calcium ammonium nitrate, CAN; urea ammonium sulfate solution, UAS, applied according to the CULTAN method; urea; urea ammonium nitrate, UAN; ammonium nitrate sulfate containing the nitrification inhibitor 3,4‐dimethyl pyrazole phosphate, Entec 26®; and a combination of liquid manure and CAN) at a nitrogen level of 180 kg N ha–1 and an additional sulfur (S) supply on grain yield, quality, Asn concentration, and the potential of AA formation of winter wheat were studied in a 2‐year field experiment. Grain yields varied between 61 und 104 dt ha–1 dry matter depending on cultivar (cv), fertilization, and year. Quality demands concerning crude protein concentration and sedimentation value were reached when CAN, CAN+S, urea, or a combination of liquid manure and CAN were applied. Asparagine concentrations in flours varied from 2.6 to 13.6 mg per 100 g flour dry matter depending on cultivar, fertilization, and year. In both years, a close nonlinear correlation between crude protein concentration and the concentration of free Asn with r²2004 = 0.93 and r²2005 = 0.94 was observed. Nitrogen fertilizers leading to high crude protein concentrations caused significantly increased Asn concentrations. In both years, a correlation between the concentration of free Asn and the potential of AA formation with r²2004 = 0.72 and r²2005 = 0.84 was found. The application of S (CAN compared to CAN+S) had no beneficial effect on the Asn concentration and the potential of AA formation, most likely because S concentration in grains was sufficient even without additional S supply.