(P06-025-25) Impact of Nitrogen Management on Nutritional and Antioxidant Properties of Hard Red Spring Wheat

Objectives: Hard Red Spring (HRS) wheat is widely recognized for its high protein content, but its nutritional and antioxidant properties have increasingly gained attention beyond baking quality. Antioxidants in wheat protect against reactive oxygen species, while phytic acid, an antinutritional factor, inhibits mineral absorption.

Methods: This study evaluated the impact of nitrogen (N) fertilization rates (0, 100, and 150 lb/acre) on phenolic and flavonoid content, antioxidant activity, and phytic acid contents in three HRS wheat varieties grown in North Dakota and Minnesota. Crucial grain quality traits, including protein content, vitreousness, 1000-kernel weight, and test weight, were also evaluated.

Results: Results revealed a significant increase (20–24%; p< 0.05) in protein content with higher N rates, alongside strong genotype-by-environment (G×E) interactions. Phytic acid levels decreased significantly (8.5 to 5.5 mg/g; p< 0.05) with higher N, showing a strong negative correlation (r = -0.8***). Both free and bound phenolic and flavonoid contents increased significantly (p < 0.05) under variable N conditions, enhancing antioxidant activities as confirmed by DPPH and ABTS assays. Total FRAP activity also improved, though free and bound FRAP exhibited less noticeable changes due to G×E effects.

Conclusions: These findings highlight the dual benefits of optimized N fertilization rates in enhancing protein content and antioxidant potential while mitigating antinutritional factors like phytic acid. The study also emphasizes on the critical role of nitrogen management in improving the nutritional and functional quality of HRS wheat, offering insights for sustainable production strategies in diverse agro-environments.

Funding Sources: North Dakota Wheat Commission, Project no: FAR0036899.