Protein Composition and Baking Quality of Wheat Flour as Affected by Split Nitrogen Application.

Cheng Xue,Andrea Matros,Karl-Hermann Mühling,Hans-Peter Mock

doi:10.3389/fpls.2019.00642

Abstract

Baking quality of wheat flour is determined by grain protein concentration (GPC) and its composition and is highly influenced by environmental factors such as nitrogen (N) fertilization management. This study investigated the effect of split N application on grain protein composition and baking quality of two winter wheat cultivars, Tobak and JB Asano, belonging to different baking quality classes. Bread loaf volumes in both cultivars were enhanced by split N application. In contrast, GPC was only significantly increased in JB Asano. Comparative 2-DE revealed that the relative volumes of 21 and 28 unique protein spots were significantly changed by split N application in Tobak and JB Asano, respectively. Specifically, the alterations in relative abundance of certain proteins, i.e., globulins, LMW-GS, α-, and γ-gliadins as well as α-amylase/trypsin inhibitors were more sensitive to split N application. Furthermore, certain proteins identified as globulins and alpha-amylase inhibitors were changed in both wheat cultivars under split N application. These results implied that the functions of these unique proteins might have played important roles in affecting baking quality of wheat flour, especially for cultivars (i.e., Tobak in the present study) the baking quality of which is less dependent on GPC.

Highlights

Grain protein concentration (GPC) is widely used as the main parameter in evaluating baking quality of wheat products and a higher price is usually achieved with high-protein bread wheat
The grain protein concentration (GPC) was only significantly increased in one cultivar (JB Asano), while remained unchanged in another one (Tobak) as influenced by split N application. These results strongly indicated that split N application caused important changes in N partitioning in grain protein, which were supposed to play key roles in determining baking quality of the resulting wheat flour
Grain yield of both winter wheat cultivars were not affected by split N application, ranging from 75 to 80 g·pot−1 (Table 1)

Summary

Introduction

Grain protein concentration (GPC) is widely used as the main parameter in evaluating baking quality of wheat products and a higher price is usually achieved with high-protein bread wheat. The baking quality is complex and is determined by GPC and by its composition (Chaudhary et al, 2016). Gluten proteins (gliadins and glutenins) play important roles in determining baking quality of wheat flour as gliadins mainly contribute to dough viscosity and extensibility, while glutenins to dough strength and elasticity (Wieser, 2007). To produce high quality wheat and to achieve optimum economic benefits, farmers make strategic decisions about the handling of N fertilization such as N rate, timing and splitting. Fractionation studies demonstrated that additional N increased GPC mainly through the enhanced gliadins and glutenins, as well as the increased proportions of HMW-GS

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Conclusion