Effect of split applications of urea on protein size distribution, physical dough properties, and baking performance of five experimental bread wheat lines

Miguel Camacho-Casas,Karla Chávez-Quiroz,Francisco Vásquez-Lara,Brenda Silva-Espinoza,Alma Rosa Islas-Rubio,María del Carmen Granados-Nevárez,Humberto Gonzalez-Ríos

doi:10.4236/as.2011.23025

Abstract

Five experimental bread wheat lines (BWL) were grown at the Yaqui Valley Experimental Station in Sonora, México during two consecutive growing cycles. The effect of five nitrogen fertilization (NF) treatments on protein size distribution (PSD), physical dough properties (PDP), and baking performance of the BWL was evaluated. Polymeric and monomeric proteins were evalu-ated by SE-HPLC. PDP were carried out by the National Mixograph and the TA-XT2 Texture Analyzer. Baking performance was evaluated using the straight dough method. Protein content (PC), main protein fractions (glutenins, gliadins, albumins-globulins), and mixograph development time (MDT) were significantly influenced by NF treatment and BWL but not by their interaction. On the other hand, PDP measured by the Kieffer rig, and baking performance were significantly influenced by the main factors (NF and BWL) and their interaction. The amount and timing of fertilizer applied to the BWL modified the PC, PSD, PDP, and bread loaf volume. PDP exhibited a larger variation in comparison to the PSD of glutenins. The split application of 150 kg of urea/ha (50-50-50) to all BWL showed a better loaf volume response than the same amount of urea applied at sowing (150-0-0). The application of 300 kg of urea/ha to all BWL, either at sowing or at three split applications of 100 kg of urea/ha each, resulted in higher flour unextractable polymeric protein (FUPP). On the other hand, the split application of 100-100-100 kg of urea/ha to three of the BWL represented the higher total unextractable polymeric protein (TUPP). Differences on PC and PSD were reflected on differences on PDP and bread loaf volume observed among the BWL.

Highlights

Wheat quality is determined by genetic and environmental factors
Protein content (PC) was significantly influenced by the bread wheat lines (BWL) and nitrogen fertilization (NF) treatment (Table 2)
The average PC of the BWL was between 10.4% and 12.2% (Table 3)

Summary

Introduction

Wheat quality is determined by genetic and environmental factors These factors affect protein content and composition, gluten functionality. Nitrogen fertilization is an important management practice that influences the amount of protein accumulated in the grain. Grain protein composition is one of the most important factors determining the breadmaking quality of wheat flour [4]. Temperature and nitrogen timing have been reported as the main environmental factors leading to variation of amount and size distribution of polymeric protein at grain maturity [7,8,9]. The influence of nitrogen fertilization on amounts and proportions of different protein types in wheat flours was reported [11]. The effect of sulfur alone or in combination with nitrogen fertilization on commercial-scale quality, mixing requirements, protein composition and dough strength has been investigated [12,13]

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