Effects of Nitrogen Application in the Wheat Booting Stage on Glutenin Polymerization and Structural-Thermal Properties of Gluten with Variations in HMW-GS at the Glu-D1 Locus.

Lijun Song,Liqun Li,Xuejun Li,Zhenzhen Liu,Liye Zhao

doi:10.3390/foods9030353

Abstract

Wheat gluten properties can be improved by the application of nitrogen. This study investigates the effects of nitrogen application in the booting stage on glutenin polymerization during grain-filling and structural–thermal properties of gluten based on the high-molecular-weight glutenin subunits (HMW-GSs) using near-isogenic lines (Glu-1Da and Glu-1Dd). The nitrogen rate experiment included rates of 0, 60, 90, and 120 kg N ha−1 applied with three replicates. Nitrogen significantly improved the grain quality traits (wet gluten contents, Zeleny sedimentation values, and maximum resistance) and dough strength (dough development time, dough stability time, and protein weakening), especially in wheat with the Glu-1Da allele. Nitrogen increased the protein composition contents, proportions of glutenins and HMW-GSs, and disulfide bond concentration in the flours of Glu-1Da and Glu-1Dd, and accelerated the polymerization of glutenins (appearing as glutenin macropolymer) during grain-filling, where nitrogen enhanced the accumulation and polymerization of glutenins more for line containing Glu-1Da than Glu-1Dd. The β-sheets, α-helix/β-sheet ratio, microstructures, and thermal stability were also improved to a greater degree by nitrogen for gluten with Glu-1Da compared to Glu-1Dd. Nitrogen treatment was highly effective at improving the gluten structural‒thermal properties of wheat in the booting stage, especially with inferior glutenin subunits.

Highlights

Bread wheat (Triticum aestivum L.) is the most widely grown cereal crop throughout the world, where it provides 20% of the total calories and 22% of the total protein, on average, in the human diet [1]
To further verify the difference in glutenin only at high-molecular-weight glutenin subunits (HMW-GSs), the glutenin compositions were analyzed by reversed phase high performance liquid chromatography (RP-HPLC)
Glu-1Dd and Glu-1Da were identical except for the HMW-GS region (Figure S1C), thereby agreeing with the results obtained by SDS-PAGE

Summary

Introduction

Bread wheat (Triticum aestivum L.) is the most widely grown cereal crop throughout the world, where it provides 20% of the total calories and 22% of the total protein, on average, in the human diet [1]. Wheat flour has extensive uses in food products, mainly because of the unique properties of gluten, which is divided into glutenins and gliadins, where the glutenins contribute mainly to the elasticity of wheat dough and the gliadins to the viscosity [2]. Due to gradual improvements in the quality of life, the requirements for a higher quality of wheat flour have grown to ensure increased acceptance by consumers. Numerous studies have focused on improving the grain quality in wheat production [3,4]. The quality of wheat is affected by the genotype, growing conditions, and their interactions [5]. Fertilization can be regulated more to affect the quality in wheat production, especially fertilization with nitrogen (N)

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